RU2126174C1 - Method determining coordinates of mobile object, method of identification of subscribers and fixing their positions, radio communication system of subscribers with central station with identification of subscribers and fixing their positions - Google Patents

Abstract

FIELD: radiolocation, radio communication with mobile objects. SUBSTANCE: characteristic feature of proposed method determining coordinates of mobile object lies in deployment of network of receivers in required number, in reception of signals of mobile objects and in establishment of their coordinates. Method of identification of subscribers and fixing their positions provides for communication of mobile object with base stations, for determination at central station with specified probability of correct reception from which zone message has come. Mentioned methods are realized with the help of communication system of mobile objects with central station. It is envisaged that receivers are placed on upper floors of buildings located on serviced territory while radio frequency communication line between subscribers and base stations is one-way line. EFFECT: reliable fixing position of mobile object and transmission of commands to it over radio communication system. 4 cl, 54 dwg, 2 tbl

Description

FIELD OF TECHNOLOGY
The invention relates to the field of radar and radio communications with moving objects (ON). A method for determining the coordinates of a moving object in the conditions of multipath propagation of radio waves is proposed. The specified method can be applied to determine the coordinates of a moving object in a city. A method for identifying multiple subscribers and determining their coordinates is also proposed. Also proposed is a device that implements both of these methods. Subscribers of a system are persons or objects that have (equipped with) a radio engineering device for transmitting radio communications to a central station (a central station calling device — HC). Persons who are the ultimate recipients of information from subscribers are called users of the system. It is assumed that users of the system are connected to the central station (CA) by communication lines and may have devices for displaying information received from the CA.

The invention has the following applications:
- Calling city emergency services (police, ambulance, fire department, etc.) in emergency situations.

 An emergency call can be made by an individual, vehicle, or property. It is assumed that the presence of an emergency is established upon the triggering of sensors installed on the HC.

 It is also contemplated that sensors can be actuated either manually or automatically. For example, a car can be equipped with sensors such as “hacking”, “starting the engine without a key”, “towing”, and “fire”, which are automatically activated and a panic button that is activated by the driver in case of an attack.

 When the sensors are triggered, an alarm signal is transmitted containing the subscriber’s identification code (IR) and the numbers of triggered sensors. The subscriber’s data are set to the CA using the identification code, for example, if the subscriber is an individual, then his passport data, if the subscriber is a car — his brand, color, state number. registration, name of the owner, if the subscriber is a property - then his address and owner.

 If it is established that the subscriber is an individual or a vehicle, the CA must determine the coordinates of the subscriber. The CA should transmit all received information to the appropriate emergency service for response.

 - Tracking moving objects. In this case, the software being monitored periodically broadcasts its identification code. At the same time as receiving the IR, the CA should determine the coordinates of the software.

 Of practical interest is tracking cars. It is advisable to include emergency patrol vehicles in the circle of vehicles that are being monitored. In this case, conditions are created under which emergency services have the ability to respond to incoming calls as quickly and efficiently as possible. It is also advisable that the tracking is carried out for public transport. At the same time, the implementation of the traffic schedule is put under tight control, the volume of traffic is automatically determined and the working hours of the drivers are taken into account. In addition, public transport stops can be equipped with pagers that inform passengers about the arrival time of the routes they need. If tracking is carried out by taxi cars, then it becomes possible to automatically call a taxi car by a client. At the same time, the executive discipline of drivers is placed under tight control. Tracking can also be carried out for any vehicle whose owner wants to exclude the possibility of misuse of the vehicle and in an automated mode to monitor discipline and take into account the working hours of drivers.

 If the number of cars that are being monitored is a significant percentage of the total number of cars in a given area, there is a fundamental possibility of solving the problem of optimal organization of traffic flows (see clause 2).

 - Search for software (stolen cars, people with inappropriate behavior, lost pets). Subscribers send their IR to the CA upon receipt of the appropriate radio command.

 Simultaneously with the receipt of the message, the CA must determine the coordinates of the software.

 - Fulfillment of auxiliary functions in the interests of various radiotelephone communication systems.

 Real-time radiotelephone communication between two subscribers can be organized with maximum efficiency if the coordinates of both subscribers are known with a high degree of accuracy. These radiotelephone communication systems can be considered external to the system in question, and the system in question can perform auxiliary functions in the interests of these systems, namely the subscriber search function and the subscriber call function of the radiotelephone communication system. It is assumed that if the subscriber wants to use radiotelephone communications, he broadcasts his IR and the number of the service being ordered. The CA determines the coordinates of the subscriber and transmits a “request” for service to the radiotelephone communication system.

- There are a number of tasks for the solution of which it is desirable to use a specialized wired communication system of the subscriber with the CA. These tasks primarily include the implementation of electronic payments (servicing credit cards). Currently, switched and dedicated telephone communication channels are used to solve this problem. Simple estimates for the conditions of Moscow show that if a significant part of payments in the city will be made using credit cards, then the information capacity of the existing telephone network in Moscow (≈10 ⁷ calls per day) will not be enough. In addition, small trading enterprises provide a large share of the turnover, for which connection to the electronic payment system using the existing technology is associated with significant costs.

 As will be seen from what follows, the implementation of the radio communication system proposed in this patent involves the deployment of a network of receiving devices with which all or almost all urban real estate is equipped. Each receiving device of the system is connected by a dedicated telephone line to a hub installed at a substation of the city telephone network. The output of the concentrator is a microwave or fiber optic communication line supplied to the CA. Despite the significant flow of radio messages received by the system as a whole, the flow of messages arriving at each individual receiving device is small. For this reason, the informed capacity of a dedicated communication line is not fully utilized. If the receiving devices have connectors for connecting external devices, then conditions are created under which it is possible to effectively solve problems that come down to two-way communication between the subscriber and the CA. Moreover, the proposed "parallel" telephone communication system has significant information capacity and is able to significantly "offload" the urban telephone network. In addition, there are simple technical solutions that exclude the possibility of unauthorized access to these communication lines. For example, when the communication line is broken, an alarm signal can be generated that is transmitted to emergency services for response.

 An important special case of the use of these communication lines is the solution of the problem of "fine" regulation of the phases of the work of traffic lights. To solve this problem, it is enough to connect the traffic light with a wire line to the nearest property, equipped with a receiving device of the system.

A schematic appearance of a radio communication system of subscribers with a central station with identification of subscribers and determination of their location is shown in FIG. 1. In FIG. 2 shows a functional diagram of the device. Explanations for FIG. 1.2 are given in paragraph 3. In all of FIG. The following notation is accepted:
1-7 receiving devices;
8 dedicated telephone line;
9 hub;
10 fiber optic or microwave link;
11 central station;
12 user system;
13 helicopter equipped with a transmitter, designed to determine the coordinates of the receiving devices after their deployment;
14 artificial earth satellite equipped with a clock transmitter;
15 system subscriber - an individual;
16 subscribers of the system - a car;
17 connector for connecting various external devices to the receiver;
18 a traffic light connected to a receiving device;
19 ATM connected to the receiving device;
20 building;
21-27 wave fronts;
28 transmitter HC;
29 microprocessor HC (MP);
30 read-only memory (ROM);
31 transmitting antenna HC;
32 receive HC antenna;
33 high-frequency amplifier (UHF);
34 detector;
35 video amplifier;
36 differentiating chain;
37 digital-to-analog converter (DAC);
38 analog-to-digital converter (ADC);
39 comparator;
40 maximum value determination circuit;
41 logarithmic amplifier;
42 antenna channel synchronization;
43 receiver channel synchronization;
44 clock pulse generator (GTI);
45 counter of clock pulses;
46 microprocessor receiving device (MP);
47 modem;
48 port of input-output;
49.50 hub memory blocks;
51 memory hub;
52 microprocessor (MP) of the concentrator;
53 isolation transformer modem mounted on a hub;
54 isolation transformer of the modem installed on the receiving device;
55 phase comparator;
56.57 isolation capacitors;
58 zener diode;
59 resistor;
60 microprocessor (MP) of a special calculator (CB);
61 central processing unit (CPU) of a special calculator;
62 data bus;
63 line of interruptions;
64 line synchronization;
65 building, located at: Moscow, st. Usievich, d 10A;
66 building, located at: Moscow, st. Usievich, d 2.

BACKGROUND
Before discussing the current level of technology, we formulate the technical requirements that must be imposed on radio communication systems designed to solve the problems formulated in the previous paragraph. Thereby, the technical result required for the successful solution of the tasks specified in paragraph 1 will be formulated.

1. To solve all the problems stated above, a system with an exceptionally high information capacity is needed, since the total number of subscribers and the total intensity of the message flow are assumed to be significant. For further estimates, we assume that in the city, which is a circle of radius R = 15 km, there are simultaneously ≈2 • 10 ⁶ cars, each of which transmits IR once every ten seconds, and ≈10 ⁷ subscribers using the HC to call emergency services (individuals, cars taken under protection, etc.), and each of these subscribers calls emergency services on average once a year, while for reliability, each call is repeated 100 times with an interval of 1..2 seconds .

 2. PO coordinates should be determined with accuracy no worse than (5-15) m.

 For example, if the accuracy of determination is (50-100) m in a city, it is impossible to reliably determine which street the given software is on or whether the software is located in the courtyard or on the front side of the building.

 3. Assuming that a certain radio communication system is used to protect a significant number of subscribers, it should be assumed that an attacker, as a rule, will commit criminal acts under the guise of misinforming and masking radio interference. If the radio communication system is sensitive to misinforming noise and cannot determine the coordinates of the masking jammer with an acceptable level of accuracy, then such a system is completely unacceptable for practical use.

Let's make a number of comments:
1. It is necessary to ensure the transmission of radio commands for software. It is assumed that radio commands change the transmission period of the infrared subscriber. Radio commands are necessary to implement software search mode, and can also be useful in software tracking mode. Indeed, let’s say that the duty officer of the territorial emergency unit “directs” the patrol car to the call point in real time using the “usual” radiotelephone communication channels. It is assumed that the dispatcher has a computer on the screen of which shows a plan of the corresponding section of the territory, on which the patrol car and the subscriber who called the emergency service are shown with dots.

 To implement this mode, it is desirable that the specified car transmits its IR at least once per second, while for tracking in "normal" mode it is enough that the car transmits IR once every ten seconds.

Existing communication channels may be used to transmit radio commands. For example, if a software search is performed in the interests of a radiotelephone communication system, radio commands can be transmitted via radiotelephone communication channels, or a separate frequency range can be allocated for these purposes. Estimates show that for a city with a population of ≈10 ⁶ ... 10 ⁷ inhabitants one transmitter is enough.

 2.To solve all the problems indicated in clause 1, there is no need to transmit messages from the central station to any particular subscriber, i.e. communication between the subscriber and the CA can be unidirectional. An exception is the transmission of radio commands for implementing the search and tracking mode software. However, the need to transmit radio commands is not a factor limiting the information capacity of the system we offer below. Therefore, we further assume that the transmission of radio commands is performed by devices external to the proposed system. In connection with the unidirectional nature of the transmission of information from the subscriber to the CA, we dwell in more detail on solving the problem of the optimal organization of traffic flows.

 Suppose that a car driver wants to determine the optimal route from one point in the city to another. The criterion of optimality may be, for example, maximum traffic safety, minimum transport costs, minimum travel time. If the vehicle is equipped with a computer in the memory of which a map of the city and the corresponding software are entered, the problem can be solved. However, the solution to this problem depends on both the parameters and the traffic intensity and speeds of traffic flows in thousands of "nodal" points of the city. If there is a representative sample of city cars whose location is tracked, for example, with a period of 10 seconds, then these parameters can be determined with a high degree of accuracy. It is important that the information received is common to all cars in the city and does not require "mailing" to specific addresses. There are many ways to make this information available to any interested person.

 Note that this information can also be used to "fine" control the phases of the work of city traffic lights, provided that the city traffic lights have a communication line with the CA.

 It would seem that the tasks formulated in paragraph 1 can be solved if a multi-position radar station is used to receive messages from subscribers (see / V. Chernyak, Multi-position radar.- M .: Radio and communications, 1993.- 416 with./). However, two serious problems arise. Firstly, determining the coordinates of software in a city is a difficult task due to the characteristics of the propagation of radio waves. Secondly, it is required to create a radio communication system capable of serving a huge number of subscribers. Further we will sequentially consider both of these problems. As analogues of our proposed method for determining coordinates, we will consider the hyperbolic method (prototype) - see / V. Chernyak. Multiposition radar. - M .: Radio and communications, 1993.- 416 pp. / And PCT patent WO 93/04453 class. G 08 G 1/127, G 01 S 3/50 1993 Well-known cellular communication systems will be considered as analogues of the method of identifying subscribers and determining their location - see / Communication with mobile objects in the microwave range. Ed. W.C. Jakes. Per. from English M .: M .: Communication, 1979, 520 S. / and the aforementioned patent WO 93/04453 (prototype). Patent WO 93/04453 is also considered as a prototype of the device and, as an analogue, the well-known satellite system for determining GPS coordinates - see, for example, PCT / WO 95/08779 cl. G 01 S 5/02, 5/10, 1/02 and WO 94/22032 C. G 01 S 5/02, 1/16, 13/00 /.

2.1 DEFINITION OF COORDINATES BY
Currently, the most accurate and common method for determining the coordinates of software is radar, known since the beginning of the 30s.

 Radar systems are divided into active and passive, depending on the presence of a transmitter of probing pulses. In active systems, the software emits a radio pulse synchronously with the arrival of the probe pulse. Passive systems do not have a transmitter of probing pulses, and the software emits radio pulses asynchronously, at previously unknown points in time.

 In radar systems, angular and range-finding methods are used to measure coordinates. Further, we will consider only range-finding methods, which have become widespread since the beginning of the 70s in multi-position radar stations (MPLS).

 In the rangefinding MPRLS to determine the coordinates of the software, the time of arrival of the radio signal of the software to several spatially separated receiving devices is measured.

Active systems use a method commonly known as elliptical / cm. Chernyak V.S. Multiposition Radar.- M.: Radio and Communications, 1993.- 416 pp. /
Active systems are unacceptable for solving the tasks specified in paragraph 1, because they have low noise immunity. Indeed, an attacker can use a low-power transmitter that simulates sounding pulses, and the misinforming signal can be shifted in phase with respect to the sounding pulse source. The HC of the protected object will transmit an alarm synchronously with the arrival of a “false” impulse, which will lead to the inability to determine the coordinates of the software. It is impossible to determine the coordinates of the director of misinforming signals due to the low required power of the transmitter.

где L_i - расстояние между ПО и i-ой приемной станцией;
i - номер приемной станции;
c - скорость распространения радиоволн;
t_i - время поступления фронта импульса на станцию i,
t₀ - момент излучения фронта импульса подвижным объектом;
x, у, z - координаты ПО;
x_i, y_i, z_i - координаты i-ой приемной станции.In passive systems, the "difference-ranging" or "hyperbolic" method is used to determine the coordinates of software. The measured values are the times of the software signal arrival at four receiving stations. From FIG. 3 it is obvious that

where L _i is the distance between the software and the i-th receiving station;
i is the number of the receiving station;
c is the propagation velocity of radio waves;
t _i is the arrival time of the pulse front at station i,
t ₀ is the moment of radiation of the pulse front by a moving object;
x, y, z - software coordinates;
x _i , y _i , z _i - coordinates of the i-th receiving station.

 Further, by definition, we assume c ≡ 1, i.e. time and distance are measured in the same units (1 μs≈300 m).

Каждое из уравнений (2) представляет собой уравнение гиперболоида. Геометрически решение системы (2) представляет собой точку пересечения 3-х гиперболоидов.The idea of the hyperbolic method is to exclude from the system of equations (1) an unknown time t ₀ . Subtracting, for example, the last equation from the first three, we obtain a system of three nonlinear equations with three unknowns:

Each of equations (2) is a hyperboloid equation. Geometrically, the solution to system (2) is the intersection point of 3 hyperboloids.

 A prerequisite for the application of radar methods is the direct visibility of the software from the receiving antennas of the MPRLS, since otherwise the signals of the software are sent to the receivers of the MPRLS after reflection from various local objects and do not carry useful information about the coordinates of the software. In this case, it is necessary to create conditions under which the signals reflected from local objects will not have a significant impact on the accuracy of determining the time of arrival of a direct beam front to the receiving antenna.

 Both of these conditions are met for space-based MPLS.

 Currently, such systems are the only really working systems that allow you to determine the coordinates of software in a city.

 Direct visibility of the software from the receiving antennas is ensured by the location of the satellite in a position close to the zenith (we can assume that the receiving antennas are located at infinite height). With this arrangement, the influence of reflected signals is eliminated, since the reflected signals propagate mainly at an acute angle to the horizon, as can be seen from FIG. 4, 5.

This figure shows the actual signal source f and its imaginary images f ', f'',f''', f ⁽⁴⁾ , constructed according to the laws of geometric optics. For simplicity, the figure shows only first-order reflections, i.e. images of imaginary sources are not shown. It can be seen from the figure that the apertures of imaginary images of sources are limited by reflective surfaces. For example, the source aperture f ″ is bounded by surface S (building wall 20). Obviously, if the satellite is at its zenith, only the actual source f and its reflection from the earth f 'are visible from the side of the satellite.

 Satellite systems for determining coordinates may require a subscriber to have a transmitter. In this case, satellite systems have low information capacity. Satellite systems are also possible in which the subscriber receives signals from several satellites and determines their coordinates in passive mode. It would seem that, having determined his own coordinates, the subscriber can transmit a message containing his coordinates via "ordinary" radio channels. However, this method is not acceptable due to the extremely low noise immunity. An attacker can have a compact low-power (at the level of microwatts) small-sized device that interferes with satellite channels. Since the power of the signal from the satellite is small, the presence of interference makes the determination of coordinates impossible. In turn, the determination of the coordinates of the jammer is impossible due to the low required power of the transmitter. We also note that in any case, a radio communication system with a high information capacity is required. The disadvantage of satellite systems is that it is difficult to make equipment for determining coordinates with a high degree of accuracy small-sized, cheap and reliable.

In addition, in real satellite systems, satellites are not at their zenith, but are visible at some acute angle to the horizon. For example, the well-known GPS satellite system uses 24 constellations of satellites to cover the entire earth's surface. Under these conditions, there are points on the earth's surface from which the antennas are visible at angles <30 ^o . Obviously, in these conditions there are vast areas of the city, within which there is no direct visibility of the antennas of the receiving devices. In these areas, the determination of coordinates with an acceptable level of accuracy is impossible.

 Currently, the possibility of using MPRLS with a "ground" arrangement of antennas for determining PO coordinates in a city is discussed only at a theoretical level in PCT patent WO 93/04453 class. G 08 G 1/127, G 01 S 3/50 1993

 In the said patent, a radio communication system is proposed, which allows, simultaneously with receiving a subscriber's message, to determine its coordinates. It is assumed that a network of transceiver devices (base stations) has been deployed in the city. Stations are located on a cellular basis with a characteristic distance between stations of the order of one mile. Antennas are mounted on the masts.

 The inventor is aware that this method of placing antennas does not provide direct visibility to most of the city from a sufficient number of receiving devices. However, according to the author, this circumstance is not an obstacle to determining the coordinates of the software.

 The main idea of the method for determining the coordinates in this patent is to use the effect of the expansion of the radio pulse in duration when it propagates in a city. According to the author, by analyzing the shape of the pulse received by the receiving device from the software, it is possible to determine the time the signal arrives at the receiving device, which would take place in conditions of direct visibility of the software from the receiving devices.

 After the correction to the time of the actual signal arrival at the receiving device is made, it is proposed to use the hyperbolic method. The disadvantage of the approach proposed in this patent is that among the many reflected rays propagating along different "paths", there are no rays arbitrarily close along the length of the optical path to the direct beam, as can be seen from FIG. 6. This figure shows the antenna of the receiving device 1 and two possible software positions - 1 and 2. In position 1, the software is located in the shaded area due to the presence of building 20. The attenuation of the direct signal passing through the building can reach 100 dB (see , for example, / Vedensky B.A. Propagation of ultrashort waves.- M .: Nauka, 1973. - p. 138-182. /). The "paths" of the reflected signals "envelope" the contours of the building 20, and when replacing the direct beam with the exact lower bound of the set of lengths of the optical paths of the reflected signals, a systematic error will be made. Moreover, suppose that the software is in position 2. Let the distance between 1 and 2 be negligible compared to the distance between 1 and the receiver, and from point 2 there is a direct visibility of the receiver. Under these conditions, the "trajectories" of the reflected signals changed only slightly, but the "trajectory" of the direct beam appeared. The appearance of a direct beam leads to an increase in the pulse duration. According to the patent, a longer correction time corresponds to a larger correction value, which should be subtracted from the actual time of signal arrival at the station, i.e. we get the opposite result from the figure in question.

Suppose that the random variable considered in the patent — the broadening of the pulse duration for points equidistant from the receiver, has a statistical spread of ± 20% for a probability level of 0.5. Given that the average value of the increase in duration is ≈3 μs, we obtain the characteristic value of the determination error t _i in (± 600 ns). In this case, with the average distances between the stations cited in the patent ≈1.6 km, the average error in determining the coordinates of the software will exceed 1 km.

 In our opinion, the main drawback of the patent in question is not the lack of an adequate way to determine the coordinates, but in the fact that the author of the patent could not offer a way to place receiving devices that provides direct visibility of most of the served territory from the antennas of the receiving devices, which, in our opinion opinion, is a prerequisite for the use of radar methods to determine the coordinates of software in the city.

Consider the problems that arise when applying the generally recognized, "classical" methods of radar to the problems we are considering:
1. Even in conditions of direct line of sight of the software from the receiving antennas of the MPRLS, the exact determination of the position of the pulse front is a difficult task due to the inertia of the receiving devices. An approximate condition is known from radio engineering that relates the passband of the receiving device Δf to the accuracy of determining the position of the pulse front ΔT:
Δf × ΔT ≈ 1 (3)
For accurate determination of the position of the pulse front at ≈10 ns, a transmission band at ≈100 MHz is required. An acceptable carrier frequency is 1 GHz. Accordingly, we obtain the bandwidth Δf / f = 0.1 with a "normal" value of this value of 0.01. The use of broadband devices leads to a significantly worse signal-to-noise ratio than in "conventional" devices. To compensate for this circumstance, it is necessary to have significant transmitter power with a small average distance between the transmitter and MPRLS receiving devices.

 Our estimates show that in relation to the tasks posed in paragraph 1, an acceptable power value is P = 20 W with an average distance between the transmitter and receiver of ≈100 m.

2. A receiver located in the line of sight of the software receives a mixture of direct and multiple reflected signals. Although the reflected signals have some delay with respect to the front of the direct signal, it is impossible to completely exclude the influence of the reflected signals on the accuracy of determining the position of the front of the direct signal. You should also consider errors associated with inaccurate system synchronization. In addition, it is desirable to use inexpensive digital devices as receivers of the MPLS. In our opinion, taking into account the above remarks, the standard error of determining the arrival times of the edges of the direct signals δt is within
δt = (10-40) ns. (4)
The indicated error, taking into account the small size of the measured distances, in practice leads to the impossibility of using the hyperbolic method. Often, with the "unsuccessful" mutual arrangement of software and receivers, the system of equations (2) either formally has no solutions, or gives errors of hundreds and thousands of meters. The corresponding example is given in clause 2.3. The analytical method we found for solving the system of equations (1) is also presented there. The indicated method can be useful in the analysis of errors of the hyperbolic method.

 A natural solution is to use more than 4 numbers of direct signals. From general considerations, it is obvious that this would lead to an increase in the accuracy and reliability of determining the coordinates of the software. However, at present, the natural generalizations of the hyperbolic and elliptic methods to the number of receiving devices greater than 4 are not known. Due to the nonlinearity of these methods, the maximum likelihood method is not applicable to them.

 3. There is another serious reason that excludes the possibility of using the hyperbolic method.

 Namely, the zone of direct visibility of the territory from the side of each MPRLS receiving device is always smaller than the zone of reliable reception of software signals. For this reason, among receivers of MPRLS there will inevitably be devices that receive reflected signals in the absence of direct ones. This problem cannot be solved by amplitude selection methods, because due to the multipath nature of the propagation of radio waves in the city, the amplitude of the reflected signal may exceed the amplitude of the direct one. The presence of reflected signals makes it impossible to use the hyperbolic method.

 Indeed, suppose that the software signal is received by 5 receiving devices, and even if it is known that 4 devices received a direct signal, and one reflected.

 The time shift of the reflected signal relative to the direct one can reach 1 μs / Communication with moving objects in the microwave range. Ed. W.C. Jakes. Per. from English M .: Communication, 1979, 520 S. /, i.e. 300 m.

Currently known methods for determining coordinates do not allow to determine which 4 of 5 stations received a direct signal. Of course, you can try to solve the problem by sequentially applying the hyperbolic method to each of the four receiving stations. However, such a method will not lead to the desired result even if, for example, there are 100 signals and it is known that 99 of them are direct. In this case, you can get C $\genfrac{}{}{0ex}{}{\text{99}}{\text{100}}$ = 100 different solutions. Since the values of t _{i are} determined with finite accuracy, all 100 obtained solutions in the general case will be different. Due to the nonlinearity of the system of equations (2), at present, no reasonable method is known that allows one to choose the “correct” ones from the obtained solutions. In particular, it makes no sense to try to take the arithmetic mean of the results obtained.

Summarizing the above, it can be argued that the following circumstances impede the solution of the tasks set in paragraph 1:
- Currently, there is no known method of "ground" placement of MPRLS receiving devices, which provides direct visibility of the city territory from the side of the number of receiving devices sufficient to determine the coordinates;
- At present, the generalization of the hyperbolic method to the number of receiving devices greater than 4 is not known, which does not allow determining the coordinates of the software with a sufficient degree of accuracy and reliability;
- Currently, a method is not known that allows you to determine the coordinates of the software in case if part of the signals received from the MPRLS receivers corresponds to direct rays, and part to the reflected ones.

2.2 RADIO COMMUNICATIONS
An essential feature of radio communication systems with software is the way to ensure multi-channel system. The following methods are known for ensuring the multi-channel system:
- distribution of subscribers by frequency ranges;
- separation of subscribers by time - each subscriber is allocated time intervals ("time windows") during which the subscriber has the right to send or receive messages;
- limiting the coverage of transceivers and the organization of communication systems on a cellular basis. The essence of cellular communication systems is the multiple use of frequency ranges and / or “time windows”, for which the served territory is divided into spatial zones (“cells”), usually close in shape to regular hexagons. At the vertices of the hexagons, transceivers ("base stations") are installed.

 The size of the spatial zone is determined during the design of the system, based on the expected number of subscribers in this zone. Typically, the cell size is from one to several kilometers. It is assumed that the software signal is confidently received by at least one base station serving this cell, and is perceived as a minor interference by base stations serving cells remote from the software.

 It should be noted that cellular communication systems are fundamentally two-way, since to ensure multichannelism, it is necessary to transmit information from each base station to the subscriber (ON). Such information allows the subscriber to determine the nearest (in the sense of better radio visibility) base station, as well as to determine frequency ranges and / or time windows for information exchange - see, for example, PCT WO 93/04453 pages 102-107. The protected provisions of the patent indicate that the radio frequency communication line between the subscriber and the base station includes means for transmitting information providing multichannel from the base station to the subscriber.

 It is also important to emphasize that the minimum distance between two base stations operating in the same frequency range and / or in the same "time windows" is deliberately chosen during the design of the system. Accordingly, the amplitude selection threshold of each base station is predetermined during system design and does not change during operation. This way of choosing the selection threshold will be called “static”.

 As mentioned above, to solve the problems posed in paragraph 1, there is no fundamental need for the transmission of information from base stations to subscribers. The use of receiving channels in the HC to obtain information providing multichannel leads to a sharp decrease in noise immunity, unjustified complication and appreciation of both the HC and the entire system.

2.3 ANALYTICAL METHOD FOR SOLVING THE "HYPERBOLIC" PROBLEM AND ANALYSIS OF THE SINFECT OF THE HYPERBOLIC METHOD
Usually, to solve the system of equations (2) of clause 2.1, or, equivalently, to solve the system of equations equivalent to it (1) (that is, to determine the coordinates of the software in the "differential-range" systems), numerical methods are used. An analytical solution to the "hyperbolic" problem will be proposed below. The advantage of our method consists in lower computational costs, and, more important for us, in the simplicity of obtaining error estimates.

найдутся хотя бы 3, образующие базис в трехмерном пространстве. 4 вектора в трехмерном пространстве всегда линейно зависимы. Поэтому всегда найдется 4 числа λ_i , таких, что :

Легко показать, что
∑ λ_i= 0 (2)
тогда и только тогда, когда концы векторов

(т.е. приемные устройства) лежат в одной плоскости ("компланарный" случай). Если концы векторов не лежат в одной плоскости, то будем считать, что величины λ_i нормированы и
∑ λ_i= 1. (3)
Пусть ПО находится в точке с координатами

. Из фиг. 3 очевидно, что

где t_i - время поступления фронта импульса на i-ое приемное устройство;
t₀ - время излучения фронта сферической волны ПО.Consider FIG. 3. We will further assume that the receiving devices do not lie on one straight line. In this case, you can always choose the origin so that from 4 vectors

there are at least 3 that form a basis in three-dimensional space. 4 vectors in three-dimensional space are always linearly dependent. Therefore, there are always 4 numbers λ _i such that:

It is easy to show that
∑ λ _i = 0 (2)
if and only if the ends of the vectors

(i.e., receiving devices) lie on the same plane (the "coplanar" case). If the ends of the vectors do not lie in one plane, then we assume that the quantities λ _{i are} normalized and
∑ λ _i = 1. (3)
Let the software be at the point with coordinates

. From FIG. 3 it is obvious that

where t _i is the arrival time of the pulse front at the i-th receiving device;
t ₀ is the radiation time of the front of the spherical wave PO.

Определив t₀ из (7), можно получить координаты ПО. Действительно, поскольку среди 4 векторов

имеется 3, образующие базис, существуют такие наборы чисел γ $\genfrac{}{}{0ex}{}{\text{(x)}}{\text{i}}$ ,γ $\genfrac{}{}{0ex}{}{\text{(y)}}{\text{i}}$ ,γ $\genfrac{}{}{0ex}{}{\text{(z)}}{\text{i}}$ , что

где

- орты осей.In the "coplanar" case, taking into account (2) (4), it is easily reduced to the form:
0 = ∑ λ _i l $\genfrac{}{}{0ex}{}{\text{2}}{\text{i}}$ -∑ λ _i t $\genfrac{}{}{0ex}{}{\text{2}}{\text{i}}$ + 2t ₀ ∑ λ _i t _i (5)
If
∑ λ _i t _i ≠ 0 (6)
then from (5) it is easy to obtain:

Having determined t ₀ from (7), we can obtain the coordinates of the software. Indeed, since among 4 vectors

there are 3 forming a basis; there exist such sets of numbers γ $\genfrac{}{}{0ex}{}{\text{(x)}}{\text{i}}$ , γ $\genfrac{}{}{0ex}{}{\text{(y)}}{\text{i}}$ , γ $\genfrac{}{}{0ex}{}{\text{(z)}}{\text{i}}$ , what

Where

- unit vectors.

Coefficients γ $\genfrac{}{}{0ex}{}{\text{(x)}}{\text{i}}$ , γ $\genfrac{}{}{0ex}{}{\text{(y)}}{\text{i}}$ , γ $\genfrac{}{}{0ex}{}{\text{(z)}}{\text{i}}$ determined by condition (8) is ambiguous, but it can be shown that the solution to the problem does not depend on the choice of coefficients.

где D_i= (l $\genfrac{}{}{0ex}{}{\text{2}}{\text{i}}$ -(t_i-t₀)²), , a t₀ определяется формулой (7).Finally we get the system of equations:

where D _i = (l $\genfrac{}{}{0ex}{}{\text{2}}{\text{i}}$ - (t _i -t ₀ ) ² ),, at ₀ is determined by formula (7).

By squaring Eqs. (9) and adding, we obtain a biquadratic equation with respect to R. (If the software does not lie in the plane of antenna location, there are always two solutions to system (9)). Solving the equation and substituting the obtained value in (9), we obtain in explicit form the expression of the coordinates through the times t _i and the coefficients of linear combinations. By expanding these expressions in a Taylor series in powers of t _i , we can explicitly obtain an expression for estimating the error of the method.

 Consider a specific example.

Легко получить:

где δ $\genfrac{}{}{0ex}{}{\text{(x)}}{\text{ij}}$ = γ $\genfrac{}{}{0ex}{}{\text{(x)}}{\text{j}}$ λ_i-γ $\genfrac{}{}{0ex}{}{\text{(x)}}{\text{i}}$ λ_j, δ $\genfrac{}{}{0ex}{}{\text{(y)}}{\text{ij}}$ = λ_i-γ $\genfrac{}{}{0ex}{}{\text{(y)}}{\text{i}}$ λ_j,
δ^(x)= (-0.001,0.002,-0.001,-0.001,0,0.001),
δ^(y)= (-0.001,0,0.001,0.001,-0.002,0.001)
Применительно к задачам, поставленным в п.1, z-координата ПО не представляет для нас интереса. Далее будем рассматривать наиболее "благоприятный" в смысле наименьшей погрешности в определении координат x, y случай, когда плоскость, в которой расположены приемные устройства, параллельна плоскости возможных местоположений ПО. В этом случае погрешность в определении z-координаты (которая неограниченно возрастает в "критических" областях вблизи любой из 2 вертикальных плоскостей симметрии, проходящих через биссектрисы квадрантов) не влияет на точность определения координат x, y. В указанных областях
∑ λ_it_i _→ 0.
Легко получить следующие простые формулы для оценки погрешности гиперболического метода в пренебрежении членами (dt_i)² и меньшими:

где:

Очевидно, (11) может быть использовано для оценок погрешности в точках непрерывности φ_i,φ_i, , т.е. вдали от областей, для которых ∑ λ_it_i _→ 0. .Let the receivers be located at the vertices of the square and have coordinates

Easy to get:

where δ $\genfrac{}{}{0ex}{}{\text{(x)}}{\text{ij}}$ = γ $\genfrac{}{}{0ex}{}{\text{(x)}}{\text{j}}$ λ _i -γ $\genfrac{}{}{0ex}{}{\text{(x)}}{\text{i}}$ λ _j , δ $\genfrac{}{}{0ex}{}{\text{(y)}}{\text{ij}}$ = λ _i -γ $\genfrac{}{}{0ex}{}{\text{(y)}}{\text{i}}$ λ _j
δ ^(x) = (-0.001,0.002, -0.001, -0.001,0,0.001),
δ ^(y) = (-0.001,0,0.001,0.001, -0.002,0.001)
In relation to the tasks posed in paragraph 1, the z-coordinate of the software is not of interest to us. Next, we will consider the most “favorable” case in the sense of the smallest error in determining the x, y coordinates when the plane in which the receiving devices are located is parallel to the plane of possible software locations. In this case, the error in determining the z-coordinate (which increases unlimitedly in the “critical” regions near any of the 2 vertical planes of symmetry passing through the bisectors of the quadrants) does not affect the accuracy of determining the x, y coordinates. In these areas
∑ λ _i t _i _ → 0.
It is easy to obtain the following simple formulas for estimating the error of the hyperbolic method in neglecting the terms (dt _i ) ² and less:

Where:

Obviously, (11) can be used to estimate the error at the points of continuity φ _i , φ _i ,, i.e. far from areas for which ∑ λ _i t _i _ → 0..

где (x_i, y_i, z_i) - координаты i-то приемного устройства.The structure of equations (10) is such that an increase (decrease) in all t _i , i = 1. ..4 by the same value of δt does not lead to changes in the coordinates estimates. For this reason, we can set t ₀ = 0 and write φ _i , φ _i as functions of coordinates (x, y, z), for which it is necessary to make a substitution in the system of equations (11):

where (x _i , y _i , z _i ) are the coordinates of the i-th receiver.

The above formulas can be tabulated as a spreadsheet. The calculation results for various software positions are shown in FIG. 7. All times and distances are given in meters, 4-dimensional vectors E_x = (φ ₁ , φ ₂ , φ ₃ , φ ₄ ), E_y = (φ ₁ , φ ₂ , φ ₃ , φ ₄ ) are dimensionless quantities. 4-dimensional vectors (dt ₁ , dt ₂ , dt ₃ , dt ₄ ) are randomly selected from the set of pseudorandom numbers distributed according to the normal law with a mean square deviation (RMS) of 9 m (30 • 10 ^-9 s).

 From FIG. 7 it can be seen that with the indicated standard deviation, the hyperbolic method is not acceptable due to the low accuracy of determining the coordinates.

, при котором приемные устройства не лежат в одной плоскости. В этом случае можно показать, что существуют наборы чисел λ_i,γ $\genfrac{}{}{0ex}{}{\text{(x)}}{\text{i}}$ ,γ $\genfrac{}{}{0ex}{}{\text{(y)}}{\text{i}}$ ,γ $\genfrac{}{}{0ex}{}{\text{(z)}}{\text{i}}$ такие, что

∑ γ $\genfrac{}{}{0ex}{}{\text{(x)}}{\text{i}}$ = ∑ γ $\genfrac{}{}{0ex}{}{\text{(y)}}{\text{i}}$ = ∑ γ $\genfrac{}{}{0ex}{}{\text{(z)}}{\text{i}}$ = 0. .In conclusion, we consider the case of the general position of vectors

in which the receiving devices do not lie in the same plane. In this case, it can be shown that there are sets of numbers λ _i , γ $\genfrac{}{}{0ex}{}{\text{(x)}}{\text{i}}$ , γ $\genfrac{}{}{0ex}{}{\text{(y)}}{\text{i}}$ , γ $\genfrac{}{}{0ex}{}{\text{(z)}}{\text{i}}$ such that

∑ γ $\genfrac{}{}{0ex}{}{\text{(x)}}{\text{i}}$ = ∑ γ $\genfrac{}{}{0ex}{}{\text{(y)}}{\text{i}}$ = ∑ γ $\genfrac{}{}{0ex}{}{\text{(z)}}{\text{i}}$ = 0..

Возведя три последних уравнения в квадрат и вычтя их из первого уравнения, получим квадратное уравнение относительно t₀. Решив его и подставив полученные решения в (14), определим координаты ПО. В общем случае получим два решения системы (14). Для выбора "правильного" решения следует воспользоваться условием:
t₀< t_i ∀i = 1...4. (15)
3. СУЩНОСТЬ ИЗОБРЕТЕНИЙ
3.1 ВВЕДЕНИЕ
В самом общем виде работа предлагаемой нами системы выглядит следующим образом:
Пусть имеется подвижный объект (ПО), оснащенный устройством вызова (УВ) центральной станции (ЦС). Пусть в некоторый, заранее неизвестный момент времени в некоторой, заранее неизвестной точке города произошло срабатывание УВ, т. е. УВ передало в эфир свой уникальный идентификационный код (ИК) и информационное сообщение. В свою очередь, в городе развернута сеть приемных устройств, связанных линиями связи с единым для всего города вычислительным центром (т. е. с ЦС). Координаты каждого приемного устройства известны с высокой степенью точности. Каждое приемное устройство определяет амплитуду поступающих радиосообщений и, если эта амплитуда превышает некоторый порог селекции, определяет время поступления радиосообщения. Принятый приемным устройством ИК, время его поступления на приемное устройство, номер приемного устройства, оценка амплитуды сигнала передается на ЦС для последующей идентификации абонента и определения его координат.Accordingly, we obtain a system of equations for determining the coordinates:

By squaring the last three equations and subtracting them from the first equation, we obtain a quadratic equation with respect to t ₀ . Having solved it and substituting the obtained solutions in (14), we determine the coordinates of the software. In the general case, we obtain two solutions of system (14). To select the "right" solution, you should use the condition:
t ₀ <t _i ∀i = 1 ... 4. (fifteen)
3. SUMMARY OF THE INVENTIONS
3.1 INTRODUCTION
In the most general form, the work of our system is as follows:
Let there be a moving object (PO) equipped with a call device (HC) of the central station (CA). Suppose that, at some previously unknown point in time at some previously unknown point in the city, an HC occurred, that is, the HC broadcast its unique identification code (IR) and information message. In turn, the city has deployed a network of receiving devices connected by communication lines to a single computer center for the entire city (i.e., to the central office). The coordinates of each receiver are known with a high degree of accuracy. Each receiving device determines the amplitude of the incoming radio messages and, if this amplitude exceeds a certain selection threshold, determines the time of receipt of the radio message. The IR received by the receiving device, the time it was received by the receiving device, the number of the receiving device, the signal amplitude estimate is transmitted to the CA for subsequent identification of the subscriber and determining his coordinates.

 Further, the information coming from a given receiving device to the CA is called a counting of the receiving device.

 The network of receivers associated with a single computer center and designed to determine the coordinates of software has been widely known since the beginning of the 70s under the name of bistatic or multi-position radar station (MPLS). However, not one of the currently known MPRLs can be used in the city because of the peculiarities of the propagation of radio waves.

 In our opinion, in the conditions of the city, the only adequate way to place MPRLS antennas is to equip almost every urban real estate with several antennas. An arrangement of antennas is illustrated in FIG. 8 and 9, FIG. 9-magnified view of the upper corner point of the building. Apparently, only with this method will conditions be created under which almost every point in the city’s territory will be in direct line of sight from a sufficient number of receiving devices. For example, in FIG. 10 shows a plan of the site of the territory of the city of Moscow (the quarter between Usievich, Chasovaya, Chernyakhovsky and Aseev streets). On the territory of this quarter there is not a single point in the line of sight, from the side of which there would be less than 15-20 points of the proposed installation of antennas, which can be easily verified by observations on the ground. A similar picture holds for other areas of Moscow. According to our estimates, with the proposed method of receiving devices placement, the zone of reliable determination of coordinates is more than 95% of the city territory.

 Due to the reversibility of the ray path, the condition of good visibility of the territory from the receiving antennas is equivalent to the condition of good visibility of the antennas from any point in the territory. For this reason, it is reasonable to call these antennas "overall", because they seem to indicate the dimensions of buildings. It is assumed that antennas and related receiving devices are placed in an intensive manner, i.e. owners of real estate objects are obligated by administrative measures to indicate the dimensions of their buildings with receiving devices of MPRLS and connect them to a dedicated telephone line connecting these devices to the CA. For each individual receiving device (unlike cellular communication systems), no design work is carried out - estimates of the estimated number of subscribers in the vicinity of this receiving device are not made, its spatial coverage is not determined, and, moreover, even a survey of the served territory is not performed . The location of the antennas of the receiving devices is predetermined by the design and location of the building. Of course, with this approach, it is possible that some individual receiving devices will be "redundant", i.e. for the entire time the buildings on which they are installed exist, these devices will not receive a single "useful" signal for us. However, from what follows (see clause 3.5), it will be seen that the receiving devices have a simple design and low cost. For this reason, the costs associated with the installation and operation of "extra" receiving devices are lower than the costs of design work. Moreover, carrying out design work requires a centralized investment, while the costs of installing and operating the receiving devices can easily be attributed to the running costs of operating the building.

It follows from the foregoing that the location of the receiving antennas of our proposed MPLS is predetermined. We cannot, as is the case with cellular communication systems, determine the geometry and dimensions of spatial zones at the design stage based on the expected number of subscribers in the vicinity of a given point in the territory and the required signal-to-noise ratio. The location of the receiving devices is determined by a number of random factors: the architect’s design, the terrain, the construction of buildings, etc. Practical measurements made by us using the electronic model of Moscow show that, with a sufficient degree of accuracy, the following mathematical model of the MPLS considered can be used:
A flat projection (top view) of the location points of the MPRLS antennas is a puncheon field of points with a distribution density that depends on the type of urban development. Namely, the distribution density is minimal for the "historical" part of urban development (the characteristic distance between the receiving devices is ≈30 m) and maximum for the "sleeping" areas (≈50 m).

 According to this model, the MPLS offered by us can be called "distributed", because the number of receivers falling on a certain section of the city’s territory is proportional to the area of this section.

 Practical observations in the conditions of Moscow show that with the proposed method of placing MPRL antennas when an HC is triggered at any point in the "historical" part of the city’s development, at least 10 direct signals will be received. When an HC is triggered in a “sleeping” area, at least 20 direct signals will be received. However, many receivers in the vicinity of the triggered HC will receive reflected signals that do not carry useful information about the coordinates of the software. Currently, no reliable methods are known to distinguish direct signals from those reflected at the stage of their reception. Indeed, due to the multipath nature of the propagation of radio waves in a city, the amplitude of the reflected signal may exceed the amplitude of the direct signal. The state of polarization of the signal, its phase, and the steepness of the front are also not reliable criteria. Our estimates show that the number of reflected signals passing the lower threshold of amplitude selection can be an order of magnitude greater than the number of direct signals (see Section 3.4).

Since the receiving device of the system is not able to distinguish between a direct signal and a reflected signal, a lot of samples arrive at the digital signal processor, only a smaller part of which corresponds to direct rays. Thus, to determine the coordinates of the software, it is necessary to solve the following problem:
Let N counts with the same IR arrive at the DS. It is known that at least K of them correspond to direct rays, N ≥ K ≥ 5.

 1) It is necessary to determine which particular samples correspond to direct rays, and 2) assuming the known distribution of errors in measuring the time of arrival of direct signals, based on the principle of maximum likelihood, to obtain the most reliable estimate of the PO coordinates.

 The method for solving this problem is described in Section 3.2 (Method for determining software coordinates). In paragraph 3.3, the results of mathematical modeling of the problems of determining the coordinates of software according to our proposed method are described.

 From clause 3.3 it follows that the invention provides the following technical result — the software coordinates are determined under conditions when it is not known in advance which receiving devices from the set of deployed receive the direct signal and which are reflected, and the software coordinates are determined with sufficient accuracy to solve problems specified in claim 1 under conditions when devices having low accuracy in determining the signal arrival time are used as receiving devices.

 Section 3.4 (Method for identifying subscribers and determining their location) sets out a method we developed for organizing information exchange between subscribers and MPLS receivers. The fundamental difference between our proposed method and the known ones (see clause 2) consists in the method of ensuring the multi-channel system. Namely, the multichannel system is provided not by transferring any information from the base station to the subscriber and not by placing the base stations on a cellular basis (that is, in such a way that the distance between two base stations operating in the same frequency range and / or in one " time window ", not lower than the set one established during system design), and by measuring the amplitude of incoming messages of subscribers at each receiving device and dynamically selecting a selection threshold - each receiving device is offline It supports the selection threshold to a level such that the number of messages passing selection threshold per unit time, equal to a predetermined set for this receiving apparatus CA commands. Moreover, during the operation of the system, the specified stream for each receiving device is refined in such a way that the total message flow passing the selection threshold is minimal, and the probability of error-free reception of the subscriber’s message is sufficient to determine the subscriber’s coordinates with a given degree of accuracy by the number of receivers in the direct zone visibility from the subscriber’s side, not lower than specified. Note that the above probability, in contrast to known systems, depends on the power of the transmitter of the subscriber - it is she who is the higher, the higher the power of the transmitter.

 The technical result achieved is to provide sufficient information capacity for solving the problems indicated in clause 1 without consciously choosing the location points of the receiving devices and estimating the number of subscribers in the vicinity of each receiving device when designing the system and without transmitting any information from base stations to subscribers, which provides high noise immunity.

 In paragraph 3.5 (Radio communication system of subscribers with a central station with identification of subscribers and determining their location), a preferred embodiment of the proposed system is considered. The device implements both of the above methods. Achievable technical result consists in solving all the tasks set in paragraph 1 in full.

3.2 METHOD FOR DETERMINING COORDINATES BY
Let an event (x ₀ , y ₀ , z ₀ , t ₀ ) occur at the point with coordinates x ₀ , y ₀ , z ₀ at time t ₀ - radiation from the front of a spherical radio wave. In the vicinity of the point x ₀ , y ₀ , z ₀ there are N receivers with known coordinates x _i , y _i , z _i , i = 1-N.

Of these N stations, no less than K are in line of sight from the side x ₀ , y ₀ , z ₀ . By definition, we introduce the quantities α _i such that α _i = 1 for direct signals and α _i = 0 for reflected signals.

"Direct" stations determine the arrival times of signals t _i , with errors δt _i , i.e.

где

- теоретическое время поступления сигнала на "прямую" станцию:

Остальные

станций принимают отраженные сигналы, также с некоторыми ошибками Δt_i: :

Далее будем предполагать, что ошибки измерения прямых сигналов не коррелированны и распределены по нормальному закону с одинаковой для всех станций дисперсией σ². Будем считать также, что математическое ожидание [δt_i] = 0 и, более того,

(4) является следствием физического принципа однородности времени. Действительно, допустим, что (4) не имеет места, т.е.

Рассмотрим два события, произошедших в одной и той же точке пространства (x, y, z) но в разные моменты времени t₀ и t₀+δt. Применив к обоим событиям любой логически не противоречивый метод определения координат, получим для этих событий одинаковые оценки пространственных координат и различные оценки для t₀, т. к. физические процессы не зависят от выбора начала отсчета временной шкалы. Иначе говоря, синхронное увеличение (уменьшение) всех t_i на одну и ту же величину

не влияет на точность определения пространственных координат, а приводит лишь к изменению оценки для t₀ на величину δt. Однако точное определение t₀ не входит в нашу задачу. Очевидно, (4) можно также записать в виде:

Для дальнейшего не существенна конкретная форма закона распределения ошибок измерения времени поступление отраженных сигналов Δt_i. Однако принципиально важно, что ∀i Δt_i - - положительная величина (при условии, что i-ая станция технически исправна), что будет видно из замечания 2.

Where

- theoretical time of signal arrival at the “direct” station:

Rest

stations receive reflected signals, also with some errors Δt _i ::

Further, we will assume that the measurement errors of direct signals are not correlated and distributed according to the normal law with the dispersion σ ² identical for all stations. We also assume that the mathematical expectation [δt _i ] = 0 and, moreover,

(4) is a consequence of the physical principle of the uniformity of time. Indeed, suppose that (4) does not hold, i.e.

We consider two events that occurred at the same point in space (x, y, z) but at different times t ₀ and t ₀ + δt. Applying any logically consistent method of determining coordinates to both events, we obtain the same estimates of spatial coordinates and different estimates for t ₀ for these events, because physical processes are independent of the choice of the origin of the time scale. In other words, a synchronous increase (decrease) in all t _i by the same amount

does not affect the accuracy of determining spatial coordinates, but only leads to a change in the estimate for t ₀ by δt. However, the exact definition of t _{0 is} not included in our task. Obviously, (4) can also be written as:

For what follows, the specific form of the distribution law of the errors in measuring the time the arrival of reflected signals Δt _{i is} not essential. However, it is fundamentally important that ∀i Δt _i - is a positive quantity (provided that the i-th station is technically sound), which will be seen from Remark 2.

в формуле (1) можно воспользоваться принципом максимального правдоподобия. Применительно к нашей задаче функция правдоподобия выглядит следующим образом:

Зафиксировав x, y, z, t₀, мы получаем выборку

мерной случайной величины δt_i. Поскольку среди всех выборок нас интересуют лишь выборки, удовлетворяющие условию (4), функцию правдоподобия можно записать как функцию, зависящую только от пространственных координат:

Из теории вероятностей известно (см., например [7]), что метод максимального правдоподобия сводится к двум условиям - оценкам для математического ожидания и дисперсии случайных величин α_i((t_i-t₀)-L_i). Указанные случайные величины, в свою очередь, зависят, как от параметров, от пространственных координат. Наша задача состоит в том, чтобы найти наиболее достоверные оценки для МО указанных величин и соответственно наиболее достоверную оценку для пространственных координат ПО.Assume that the coefficients α _i are known to us. Then for estimates of nonrandom variables

in formula (1), we can use the principle of maximum likelihood. For our task, the likelihood function is as follows:

Fixing x, y, z, t ₀ , we get a sample

random variable δt _i . Since among all the samples, we are only interested in samples satisfying condition (4), the likelihood function can be written as a function that depends only on spatial coordinates:

It is known from probability theory (see, for example, [7]) that the maximum likelihood method reduces to two conditions - estimates for the mathematical expectation and variance of random variables α _i ((t _i -t ₀ ) -L _i ). The indicated random variables, in turn, depend, as on parameters, on spatial coordinates. Our task is to find the most reliable estimates for the MO of the indicated values and, accordingly, the most reliable estimate for the spatial coordinates of the software.

что автоматически выполняется в силу условия (4).In relation to our problem, the equation for MO should be written in the form:

which is automatically satisfied by virtue of condition (4).

Далее, вместо функции (7) мы будем рассматривать функцию (8), предполагая дисперсию σ² известной:

Далее функцию (8) мы будем называть функцией правдоподобия
Очевидно, в точке местоположения ПО МО Λ(x₀,y₀,z₀) равно единице. Пусть

координаты точки глобального минимума (8). Очевидно,

Очевидно также, что, выбирая в качестве оценки для (x₀, y₀, z₀)

, мы делаем систематическую ошибку. Нам следует показать, что при достаточно большом числе прямых сигналов указанная оценка является асимптотически несмещенной и сделать оценки для получаемой погрешности. Математически строгое решение этой задачи связано со значительными трудностями и выходит за рамки настоящей работы. Для обоснования указанного предположения мы будем использовать результаты численного моделирования на ЭВМ реальных задач определения координат ПО в условиях города. Полученные результаты подробно рассмотрены в п.3.3, там же приведены грубые эмпирические оценки для получаемой погрешности.The second condition reduces to the fact that, as an estimate for the variance, the value of function (7) is selected at the point of its global minimum, or, also, at the point of global maximum of function (6):

Further, instead of function (7), we will consider function (8), assuming the variance σ ^{2 to be} known:

Further, we will call function (8) the likelihood function
Obviously, at the point of the PO MO Λ (x ₀ , y ₀ , z ₀ ) is equal to unity. Let be

coordinates of the global minimum point (8). Obviously

It is also obvious that, choosing as an estimate for (x ₀ , y ₀ , z ₀ )

, we make a systematic error. We should show that for a sufficiently large number of direct signals, this estimate is asymptotically unbiased and make estimates for the resulting error. A mathematically rigorous solution to this problem is associated with significant difficulties and is beyond the scope of this work. To justify this assumption, we will use the results of computer numerical simulation of real problems of determining the coordinates of software in a city. The results obtained are discussed in detail in Section 3.3; rough empirical estimates for the resulting error are also given there.

Таким образом, при использовании гиперболического метода в качестве оценки координат ПО выбирается точка глобального минимума функции (11) или, что тоже, функции (8). Из сказанного следует, что гиперболический метод является тривиальным частным случаем предлагаемого нами общего метода (при условии, что система уравнения (1) п.2.1 имеет решение).Remark 1. Let N = K = 4. Then, to determine the coordinates of the software, one can use the hyperbolic method (system of equations (2) of clause 2.1 or the equivalent system of equations (1) of clause 2.1). The indicated system of equations may either have no solutions or be satisfied on some finite or infinite set of points. For each solution to this system, there is a
L _i - (t _i - t ₀ ) = 0, i = 1-4 (10)
Or, equivalently,

Thus, when using the hyperbolic method, the global minimum point of function (11) or, what is more, function (8) is selected as an estimate of the PO coordinates. It follows from what has been said that the hyperbolic method is a trivial particular case of the general method we are proposing (provided that the system of equation (1) of clause 2.1 has a solution).

Until now, we have assumed the coefficients α _{i to be} known. Next, a method will be described to determine these coefficients.

 For clarity of further reasoning, we use the physical principle of reversibility of the ray path and we will consider a problem that is completely equivalent to ours in the sense of the obtained solutions.

Further, we assume that the HC is a receiving device, while the receiving devices MPLS are transmitters. Each i-th “transmitting” MPLS device at the time t ₀ “emits” a spherical radio wave whose front at the time t _i arrives at the software location. The foregoing is illustrated in FIG. 11. This figure shows a section of an urban area (top view). Buildings 20 are equipped with receiving devices 1-7. The wavefronts 21,22,23,24,25 correspond to direct rays, and the 26th and 27th front correspond to reflected ones. The advantage of this approach is that, considering a certain point in space, we are not obliged to assume that it is at this point that the software is located. (The geometric picture of the propagation of radio waves does not depend on the presence or absence at any point in the receiver.)
Let us make a remark important for the future and obvious from the point of view of modern physical concepts.

Действительно, в противном случае пришлось бы предположить, что сигнал распространяется со скоростью, превышающей скорость света.Remark 2. The path traveled by the k-th reflected signal always exceeds the distance between the location point of the hydrocarbon and the k-th station:

Indeed, otherwise, one would have to assume that the signal propagates at a speed exceeding the speed of light.

In accordance with the foregoing, the shock wave is always located inside the sphere formed by the front of the reflected signal, as shown in FIG. 11. It can be seen from the figure that the times t _{i are} determined with a finite degree of accuracy - otherwise the fronts of the direct rays would intersect at one point.

 Let us introduce a number of definitions important for the future.

Назовем величины Φ_i(x,y,z) = t_i-L_i невязками.For each point with coordinates x, y, z, consider N quantities:

We call the quantities Φ _i (x, y, z) = t _i -L _i residuals.

The array {Φ _i } can be sorted in ascending order Φ _i , that is, so that
Φ $\genfrac{}{}{0ex}{}{\text{(k)}}{\text{i}}$ ≥Φ $\genfrac{}{}{0ex}{}{\text{(l)}}{\text{l}}$ ∀k> li, j, k, l = 1-N. (fourteen)
We call the kth residual the residual in kth position in the sorted array {Φ _i }
Note that by sorting the array {Φ _i }, we thereby obtain an ordered set of numbers of receivers {i _n }, where the number (lower index in formula (13)) of the receiving device giving the kth the size of the residual.

условными невязками.Suppose that we have made any assumptions about the value of the time coordinate of the event t ₀ . Then we call the quantities

conditional discrepancies.

 An array of conditional residuals can also be sorted. In the future, the first (i.e., the smallest of all) conditional discrepancy is of most interest to us.

 The above definitions have obvious consequences.

Firstly, taking into account Remark 2, for physically feasible cases, provided that the receiving devices are in good working order at the software location point, the conditional discrepancy cannot be an arbitrarily small negative value. As a practically working criterion, we assume that at the point of software location for the first conditional discrepancy, the following inequality holds:
t _i -t ₀ -L _i > -1.5σ. (fifteen)
Further, we assume that a station for which condition (15) is not fulfilled at the software location point or is technically faulty, or there is some special case that will be considered later. Our proposed method allows us not only to determine the coordinates of the software, but also in the process of solving each specific task, to test the receiving devices, which is extremely important, since the total number of receiving devices is assumed to be significant (≈10 ⁵ for the conditions of Moscow). Further, up to Remark 3, we assume that all receiving devices are operational and, moreover, (15) holds.

Further, conditional residuals satisfying the condition
t _i - t ₀ - L _i <0 will be called negative.

Accordingly, conditional residuals satisfying the condition
t _i - t ₀ - L _i > 0
will be called positive.

The meaning of condition (15) is as follows. Suppose we made the assumption that the event occurred at a point with coordinates (x, y, z, t ₀ ). If (15) does not hold, then the assumption of the coordinates of the event should be considered erroneous. In the future, we will assume that the fronts of direct signals fall in 1.5σ — the vicinity of the PO location point, while the fronts of the reflected signals are outside this neighborhood. Moreover, at the software location, the reflected signals always have a positive residual. If some signal has a negative conditional discrepancy at the software location, we must assume that this signal corresponds to a direct beam.

 Obviously, if (15) holds for the first conditional residual, then (15) will be all the more true for conditional residuals with large numbers. In turn, if (15) does not have a place for the kth conditional discrepancy, then (15) all the more, there will be no place for the k-1st and more minor discrepancies.

 Consider a point in space with coordinates (x, y, z) and assume that the software is located at this point. Let it also be known that of the N received signals, K correspond to direct rays.

We compute N quantities L _i and N residuals Φ _i (see (13)).

Определив коэффициенты α_i, из формулы (4а) получаем оценку для t₀, а из формулы (8) значение функции правдоподобия. Перебрав, например, с шагом в 1 м все возможные значения координат (x, y, z), мы можем найти точку глобального минимума (8), которую и следует использовать в качестве оценки координат ПО. В п.3.3 будет показано, как по известной величине функции правдоподобия в точке ее минимума определить окрестность, в пределах которой ПО находится с заданным уровнем вероятности.Sort the array of residuals {Φ _i }.
Further, from the entire N-element signal set, we will consider its K-element ordered subset {i _n } where 1 ≤ n ≤ K. If the assumption that the software is at a point with coordinates (x, y, z) is true, then we must assume that the indicated K signals correspond to direct rays. Indeed, if the array of residuals and the array of conditional residuals are ordered, then for any quantity t _{0 the} sequence of the numbers of receivers {i _n } in both arrays will be the same. If the assumption about the spatial coordinates of the software is true, then there exists t ₀ such that the edges of the direct signals fall into 1.5σ — a neighborhood. If the signal with the number i _k is outside the specified neighborhood, then the signals standing at k + 1 and subsequent places in the array {i _k } are all the more outside this neighborhood. The following statement is also true: if the signal with the number i _k falls in the specified neighborhood, then in the same neighborhood there are signals located at previous positions in the array {i _n }, since it is assumed that condition (15) is satisfied for the point under consideration. In accordance with the foregoing, the coefficients α _i can be calculated as follows:

Having determined the coefficients α _i , from formula (4a) we obtain an estimate for t ₀ , and from formula (8) the value of the likelihood function. After going over, for example, with a step of 1 m, all possible coordinate values (x, y, z), we can find the global minimum point (8), which should be used as an estimate of the PO coordinates. In Section 3.3, it will be shown how to determine the neighborhood within which the software is located with a given level of probability using the known value of the likelihood function at its minimum.

Пусть в некоторой точке (19) не имеет места. Рассмотрим сферу радиуса R с центром в указанной точке. В каждой точке указанной сферы величины L_i могут получить приращение не более, чем ±R. Легко показать, что, если (19) не имеет места в некоторой точке, то (19) не может иметь места внутри сферы радиуса

с центром в указанной точке.Obviously, iterating over all possible coordinate values involves significant computational overhead. Nevertheless, the problem can be successfully solved if parallel computations are used (see clause 3.5.4). However, the amount of computation can be reduced by several orders of magnitude if condition (15) is used. Indeed, taking into account (4a) (15), it can be written as:

Suppose that at some point (19) does not hold. Consider a sphere of radius R centered at a specified point. At each point of the indicated sphere, the values of L _i can receive an increment of no more than ± R. It is easy to show that if (19) does not have a place at some point, then (19) cannot have a place inside a sphere of radius

centered at a specified point.

 The relevant area should be excluded from consideration.

There is a simple iteration method that can further reduce computational overhead. Consider FIG. 11. This figure shows the software location point and 1.5σ is the neighborhood of this point. When constructing the figure, the actual value of t _{0 was} used as an estimate for the time coordinate of the event. The location of the receivers in this figure (in contrast to Fig. 12) is such that for any point outside the 1.5σ - neighborhood there is at least one negative conditional discrepancy. As a first approximation, we choose an arbitrary point with coordinates (x, y, z) outside 1.5σ — the neighborhood of PO. For the selected point, calculate the values of L _i , residuals t _i - L _i and sort the array of residuals. Consider the first element of the array and set the station number n corresponding to the specified element. We did not make any assumptions about the time coordinate of the event, however, it can be argued that for the “true” value t _{0, the} signal with number n has a negative conditional discrepancy at the point in question. Draw a segment from the point in question to station n. As the next approximation, we choose a point on the indicated segment at a distance determined by formula (20) from the current approximation. Obviously, the method ceases to converge at 1.5σ - a neighborhood of the PO location point. In the indicated neighborhood (if we are not satisfied with the accuracy of 1.5σ), we should use the direct method - enumeration by coordinates.

 Obviously, the method does not work with the arrangement of receivers shown in FIG. 12. This figure shows a section of the city. It is assumed that all the corner points of the buildings are equipped with receiving devices (not shown in Fig.) And wave fronts of direct rays. In the shaded area, the residuals are positive. Such geometry is an exception to the general case with the proposed method of placing receiving devices. Applying the iteration method under the conditions shown in this figure, we quickly fall into the shaded area, after which the method loses convergence.

We intend to leave aside the question of rigorous justification of the iteration method, since many different modifications are possible. However, it is essential that all possible modifications of the iteration method, as well as the method we propose, are generally based on the following provisions:
1. As an estimate of the PO coordinates, the global minimum point of function (8) is used.

2. To calculate the value of function (8) at a given point (x, y, z), it is necessary to perform the sequence of the following steps:
a) using formula (13) to calculate the array of residuals {Φ _i };
b) sort the specified array in increasing order of Φ _i ;
c) put α _i = 1 for signals corresponding to the first K elements of the sorted array and α _i = 0 for the remaining signals;
d) determine t ₀ from condition (4a) and substitute the obtained values in formula (8).

H. If we made the assumption that the software is located at a point with coordinates (x, y, z), then at the indicated point the first conditional discrepancy for which t ₀ is determined from condition (4a) cannot be arbitrarily small negative value.

Another approach is also possible, consisting in the fact that when considering a certain point in space we do not make the assumption that the software is located at this point. However, whatever the “true” time t ₀ and the “true” coordinates of the software are, if there is at least one negative discrepancy for the point under consideration (with the “true” t ₀ and the “true” software coordinates), we can always install a receiving device that gives the most negative residual for a given point. To do this, it is enough to sort the residual array for the given point - the first residual element will always correspond to the receiver, which has the most negative residual at the point in question. An example of the application of this approach is given in § 3.3.

 Remark 3. Until now, we assumed that at the point of location of the software, the following takes place (15). However, in reality (15) may not take place either due to purely random reasons (the probability of fulfillment of (15) at the software location point is 0.94) or due to malfunctioning of receiving devices. Due to the significant number of receivers and difficult operating conditions, the failure flow rate can be significant. It is desirable that simultaneously with the determination of the software coordinates the testing of receiving devices is carried out - in this case the system under consideration will be capable of self-organization.

 Practical estimates show that the number of direct signals arriving at the digital center during each operation of the shock wave usually exceeds the number of signals needed to determine the coordinates of the software with a given degree of accuracy (see Section 3.3). Let there be l “extra" signals (l≈1-3), i.e. To determine the coordinates with a given degree of accuracy, K direct signals are sufficient, while the software is in direct line of sight from the K + 1 side of the receiving devices. Obviously, the method described above will be fully functional if, after each sorting of the residual array, we will exclude from it no more than l first elements, if condition (15) is not fulfilled for them. The advantage of this approach is that we will determine the coordinates of the software in the event of a malfunction of a certain number of receiving devices.

 Having determined the coordinates of the software, we can calculate the residuals for all N signals received at the station and enter the data into the appropriate database. During statistical processing of this database, receivers that “send” the least reliable samples to the CA can easily be identified (see clause 3.4, clause 3.5.4).

3.3 RESULTS OF MATHEMATICAL MODELING AND EVALUATION OF THE ERROR OF THE METHOD FOR DETERMINING THE COORDINATES BY
The mathematically rigorous justification of the method for determining the coordinates described in the previous paragraph is a complex problem that goes beyond the scope of this paper. We will focus on the results of mathematical modeling of problems of determining coordinates in a typical area of a city. As such a district, we will consider a section of the territory of the city of Moscow adjacent to ul. Usievich on the site from the house N 10 ^a to the house N 2. A schematic plan of the site is shown in FIG. 10, 65-st. Usievicha d N 10 ^a, 66 ul. Usievich d N 2.

 It is assumed that all the houses shown in the figure are equipped with MPRLS receiving devices according to the method described in clause 3.1. In this case, there are 116 receiving devices on the site. In direct visibility from each point of the site there are at least 20 receiving devices, and the distance to the most remote receiving device from the specified 20 does not exceed 120 m. If coordinates are determined using 12 or 10 direct signals, the distance from any point in the territory to the most remote " direct "station does not exceed 80 m. (Only points in the central part of the site should be considered, since for points on the periphery of the site, receiving devices located outside the boundaries of the site are significant).

 To solve the problems posed in paragraph 1, the z-coordinate of the software is not of interest. Further, we will assume the known "relief" of the territory, i.e. the height of each point of the territory relative to a certain conditional level depending on the coordinates x, y: z = φ (x, y). Since the antenna height PO h relative to the earth’s surface is known, the global minimum point of the likelihood function on the surface (x, y, φ (x, y) + h) can be used as an estimate of the coordinates. It will be shown below that the errors in determining the quantity φ (x, y) + h weakly affect the accuracy of determining x, y.

 For the area under consideration, the earth's surface can be approximated by the z = 0 plane (receivers have a z coordinate other than 0, see Fig. 13. The coordinates of the lower left corner of Fig. 10 are taken as (0,0)). Column 2 of the table shows the numbers of stations (receivers), and column 3 shows their coordinates. The symbol "d" in column 1 of the table indicates the station, when entered, indicated as "direct". For these stations, a random value distributed according to the normal law (column 5) with M.O. = 0 and standard deviation = 6.0 m (20 ns) (column 6 = column 4 + column 5 is added to the theoretical value of the signal arrival time (column 4)) ), the signal arrival time for stations receiving the reflected signals is increased by a random value distributed evenly over the interval (15,150).

 All data are given in meters.

Mathematical modeling was carried out according to the following algorithm:
1. The PO location point (x ₀ , y ₀ ) was selected within the central part of the site and the signal emission moment t ₀ . 20 different points were chosen. The statistical results for all selected points coincided with an accuracy of ± 20%, and then we consider a “typical” point with coordinates (150,150.0).

где L_i - расстояние между i-ым приемным устройством и ПО;
4. Для приемных устройств, находящихся в зоне прямой видимости со стороны ПО, вычисленные величины

увеличивались на случайные величины

распределенные по нормальному закону с математическим ожиданием (МО), равным 0, и заданной величиной среднеквадратического отклонения (СКО). Рассматривались СКО от 10•10^-9 с до 100•10^-9 с (от 3 до 30 м). Для устройств, находящихся вне зоны прямой видимости со стороны ПО,

увеличивались на случайные величины Δt_i, распределенные по закону равномерной плотности на отрезке [15,150].2. For each selected point, receiving devices located in the line of sight from the side of the selected point were determined. The coordinates were determined by K = 20, 12, 10 direct signals;
3. For all 116 receivers, the theoretical signal arrival times were determined

where L _i is the distance between the i-th receiving device and software;
4. For receivers located in the line of sight from the software side, the calculated values

increased by random values

distributed according to the normal law with a mathematical expectation (MT) equal to 0 and a given value of standard deviation (RMS). RMS from 10 • 10 ^-9 s to 100 • 10 ^-9 s (from 3 to 30 m) were considered. For devices outside the line of sight from the software side,

increased by random values Δt _i distributed according to the law of uniform density over the interval [15,150].

5. Sorted all received t _i in ascending order. The minimum element t _{min was} determined and signals for which t _i - t _min > R _max • R _{max were} chosen so as to minimize, on the one hand, the number of processed signals and, on the other hand, were not excluded from further consideration of none of the K direct signals. For K = 20, R _max = 180 m was chosen and the total number of processed signals N was N = 30-70. For K = 10.12, R _max = 120 m and N = 15-30. A special case N = K = 20 was also considered.

выбиралась точка, в которой функция правдоподобия принимала наименьшее значение. Для оценки влияния погрешности определения φ(x,y)+h на величину погрешности определения координат поиск минимума проводился также на плоскостях z = 10 м и z = -10 м.6. According to the method described in clause 3.2, the likelihood function values were determined at the “nodal” points with coordinates x = jΔ, y = kΔ z = 0 where j, k = 0 ... 100, Δ = 3 m. As software coordinate estimates

a point was chosen at which the likelihood function assumed the smallest value. To assess the influence of the error of determination of φ (x, y) + h on the value of the error of determination of coordinates, the search for a minimum was also carried out on the planes z = 10 m and z = -10 m.

Рассмотрим основные полученные результаты.7. For each point selected according to claim 1, at least 1000 times the paragraphs were performed. 4,5,6. Based on the solved problems, histograms of the error distribution were built

Consider the main results obtained.

For N = K = 20, x ₀ = 150 m, y ₀ = 150 m, z = 0 m and standard deviation = 100 ns (!), Standard deviation = 50 ns, the results are shown in FIG. 14 and 15.

For K = 20, R _max = 180 m (N = 30-70), the same PO coordinates and RMS = 50 ns, the results are shown in FIG. 16. The figure shows that the presence of "extra" signals reduces the accuracy of determining the coordinates. Acceptable accuracy is ensured with a standard deviation of ≤ 30 ns - see FIG. 17 and 18.

For K = 12, R _max = 120 m (N = 15-30), standard deviation = 20 ns, standard deviation = 15 ns, the results are shown in FIG. 19 and 20.

In FIG. 21, 22 show the results for K = 10, R _max = 120 m (N = 15-30), standard deviation = 15 ns, standard deviation = 10 ns.

In FIG. 23,24 shows the results of solving the problem in the case when the solution was sought on the planes z = 10 and z = -10 (the software was at the point with coordinates x = 150, y = 150, z = 0) R _max = 120 m, K = 10, N = 15-30. It can be seen from the figures that the inaccuracy in determining the z - coordinate weakly affects the accuracy of determining the x and y coordinates.

 In FIG. 25 shows the results for K = 10 and N = 116 (no sorting was performed) for the standard deviation = 10 ns.

In addition to the “direct” method, coordinates were also determined by the iteration method. The algorithm coincided with the above with the exception of clause 6. With respect to the iteration method, clause 6 is formulated as follows:
6a. The first approximation was chosen arbitrarily (including the points spaced tens of kilometers from the point of location of the software as the first approximation);
6b. For each next approximation, the array of residuals was calculated and sorted. According to 4a of Section 3.2, an estimate was calculated for t ₀ (moreover, α _i = 1 for the first K elements of the sorted array of residuals). The next approximation was chosen at a distance Δ = 3 m from the previous one in the direction of the station that gave the smallest (i.e., most negative) discrepancy.

6c. The current approximation was chosen as an estimate of the PO coordinates if the estimate for t _{0 of the} next approximation turned out to be lower than that of the current one.

The results for K = 10, R _max = 120, x = 150, y = 150, z = 0 are shown in FIG. 26.

где n = K- 1, a χ² известное хи-квадрат распределение. С вероятностью 0.99 указанная величина не превышает 2.4. Соответственно, для данной выборки случайных параметров с вероятностью 0.99 ПО находится в показанной на рисунке области.In FIG. Figure 27 shows a typical zone of possible software locations for some sample of random parameters δt _i , Δt _j . For the indicated sample, the minimum likelihood function was found. It is easy to show that at the location of the software, the likelihood function is distributed according to the law

where n = K- 1, a χ ^{2 is the} known chi-square distribution. With a probability of 0.99, the indicated value does not exceed 2.4. Accordingly, for a given sample of random parameters with a probability of 0.99, the software is in the region shown in the figure.

From the above results it follows that an acceptable accuracy of determining the coordinates with not very stringent requirements for the accuracy of determining t _i for direct signals is achieved at K = 10 and RMS = 15-20 ns. It is also obvious that in order to ensure the maximum accuracy in determining the coordinates, it is necessary to exclude "unnecessary" signals from consideration, for which, during the operation of the system, the radius of its "zone of responsibility" should be clarified for each receiver (see clause 3.4, clause 3.5. 4).

3.4 METHOD FOR IDENTIFICATION OF SUBSCRIBERS AND DETERMINATION OF THEIR LOCATION
In this paragraph, we consider a method of organizing information exchange between a subscriber and receiving devices of the system.

 We make a number of comments.

 1. To solve all the problems posed in Clause 1, it is sufficient that the volume of the message transmitted by the subscriber with each call to the CA be ≈100 bits (8-12 bytes).

 Indeed, to solve the problems of tracking software and searching for software, it is necessary to broadcast only the subscriber’s identification code. In the mode of calling a subscriber of emergency services or radiotelephone communication systems, in addition to infrared, the number of the called emergency service, the numbers of triggered HC sensors, the number of the services ordered from the radiotelephone communication system are transmitted (see point 1), i.e., also insignificant (within 1 -2 bytes) the amount of information.

Of interest to us are signals (messages) only from an HC located in the line of sight of the MPLS receiver. In addition, the distance between the receiving device and the HC is small and usually does not exceed 300 m. Under these conditions, 200 • 10 ^-6 s is sufficient to transmit a message with a volume of 100 bits. Indeed, the main factor limiting the data transfer rate in a city is intersymbol interference. The reason for this phenomenon is to increase the pulse duration due to multipath propagation. If, for example, a zero bit is transmitted after a single bit, then the zero bit will be received against the background of the tail of a single bit, see FIG. 28, 29. In FIG. 28 shows the envelope of the initial pulse, and FIG. 29 - a characteristic form of an impulse after its propagation in a city. (The scale along the vertical axis is not shown, since the waveform is of interest to us, not the value of its amplitude. It also applies to all subsequent diagrams). At high data rates, it is possible to recognize a zero bit as a single bit.

Let the distance between the HC and the receiver be 300 m. The time allocated to transmit one bit is 2 • 10 ^-6 s. Intersymbol interference will be possible provided that the amplitude of the echo signal delayed by 2 μs with respect to the front of the direct signal is large. The specified echo signal can be considered as a signal from some fictitious source having a power equal to the power of the actual source and located from the receiving device at a distance of 900 m. It will be shown below that under the most adverse conditions the amplitude of the signal of the fictitious source will be more than three times lower than the amplitude of the actual source. It will be seen from what follows that the amplitude of the signals arriving at the receiving device is measured in some way. Under these conditions, the possibility of errors in receiving data due to intersymbol interference is excluded.

Each single bit in the subscriber's message is a wave train (see clause 3.5). Since even with a software speed of 150 km / h during a message transmission time of 200 • 10 ^-6 s, the software movement is ≈ 8 mm, i.e. small value in comparison with the long wavelength of the radiation used, the transmission conditions of both the first and all subsequent bits of the message are the same. Accordingly, the shape and amplitude of all individual message pulses are the same.

 2. Next, by the availability factor, we understand the probability of error-free reception of a subscriber’s message sufficient to determine the coordinates with a given degree of accuracy by the number of MPRLS receiving devices. System subscribers can be divided into groups.

 Next, we will classify the first group as subscribers who give a combination of low message flow intensity and higher requirements for the system availability factor (≈ 0.99). This group, for example, includes subscribers calling emergency services.

 The second group will include subscribers who give a significant stream of deliberately redundant messages and present low requirements for the availability factor (≈ 0.80-0.90). Such subscribers primarily include vehicles that are monitored for optimal traffic management.

 We will assume that all subscribers within the same group have transmitters with the same power.

3. For definiteness, all further estimates will be made for a city whose territory is a circle of radius R = 15 km. We assume that in the city there are ≈10 ⁷ subscribers of the first group, the total message flow rate of which is ≈ 30 s ^-1 , and ≈ 2 • 10 ⁶ subscribers of the second group, giving the message flow rate at the level of 2 • 10 ⁵ s ^-1 (see point 1, remark 1). We will also assume that the message flow is a stationary Punson flow. Assumptions about the distribution of spatial coordinates of subscribers will be made later.

 4. Further, we will assume that all HCs (and, accordingly, all MPLS receivers) operate in the same frequency range.

 Above (see clause 3.1), we proposed a method for the placement of receiving antennas MPLS. We had to choose such a method, because at a finite antenna height only this method provides direct visibility of a larger (≈ 95%) part of the city territory from the side of the number of receiving devices sufficient to determine the PO coordinates.

 However, it turns out that our proposed method of placing the receiving antennas of MPLS leads to an extremely simple and effective way of organizing information exchange between the subscriber and the CA.

 Namely, there is no need to divide subscribers by frequency ranges and / or "time windows". Subscribers of the system can transmit messages asynchronously, at arbitrary points in time, while the availability coefficient remains within the specified limits.

 We make some important definitions.

Let, based on the considerations set forth in Section 3.3, we choose the minimum number of direct signals K necessary for determining the software coordinates. Let the probability of error-free reception of a subscriber message by each receiver be equal to P and the probability of error-free reception of a subscriber message simultaneously by K devices P ^K less than the required availability factor . Then we will consider that conditions are created under which the subscriber is in the line of sight from the K '> K side of the receiving devices. K 'is selected with some margin, i.e., for example, if K = 10 direct signals are sufficient for determining coordinates with a given accuracy level, we select K' = 12. Obviously, with this approach, the loss of subscriber message on some individual receiving devices is not makes it impossible to determine the coordinates of the subscriber. Detailed estimates will be made by us below.

Let the subscriber of the system be at the point with coordinates (x, y, z). Consider the set of all MPRLS receiving devices located in the line of sight from the indicated point. We calculate the distance L _i between the specified point and each of the receivers of the specified set. Sort the resulting array and consider the first K 'of its smallest elements.

We call the quantity R _{K ′} = L $\genfrac{}{}{0ex}{}{\text{(K ′)}}{\text{i}}$ the radius of the virtual zone.

Obviously, the radius of the virtual zone is not a continuous quantity. Small changes in coordinates can lead to an abrupt increase (decrease) in the radius of the virtual zone. A typical value of this value is determined by the type of urban development. For example, for the example considered by us in Section 3.3 (see Fig. 10) at the point (150,150,0) we have:
R ₈ = 56 m, R ₁₀ = 63 m, R ₁₂ = 109 m, R ₁₆ = 118 m, R ₂₀ = 129 m.

We call a virtual zone a region of space enclosed within a sphere of radius R _{K ′} centered at the subscriber’s location.

 If we compare our system with well-known cellular communication systems, then the virtual zone can be considered as an analogue of a cellular communication cell.

 For each receiver of the MRLS, a region of points can be constructed, for each of which the indicated receiver is included in K ', the elemental set of receivers closest to the point in question that are in the line of sight from this point.

We call the zone of responsibility of the ith receiver the set of space points (x, y, z), such that, firstly, the specified receiver is in the line of sight from the specified point and, secondly, the distance L _i between the specified the receiving device and the specified point does not exceed the radius of the virtual zone R _To calculated for the considered point.

 Obviously, the ideal situation would be when messages arriving at the receiver from its area of responsibility would be transmitted to the CA, and messages arriving from subscribers outside this zone would be ignored. However, there is no reasonable way to solve this problem. For this reason, we are forced to put up with the fact that the receiving device receives and transmits to the CA not only "useful" signals from the area of responsibility, but also a significant number of "extra" signals.

Further, we will assume that each receiving device in some way estimates the amplitude of the incoming signals and transmits to the DS only signals whose amplitude exceeds a certain threshold. When radio waves propagate in a city, the shape of the pulse is distorted. For this reason, ambiguity arises when determining the amplitude value. Typical envelope shapes are shown in FIG. 30 to 33, FIG. 30 - envelope of the original signal, FIG. 31 - 33 envelopes of signals received at different points of the city at the same distance from the transmitter. In FIG. 31 - 33 also shows a certain selection threshold U _- . It can be seen from the figure that due to the interference of many random reflected signals, an increase in the maximum pulse amplitude can occur.

Previously (see clause 2.1), it was noted that for the implementation of the present invention it is necessary to create conditions under which it would be possible to accurately determine the position of the front of the direct beam. Such conditions include the use of broadband receivers and the use of transmitters with excess power. The pulse front is the vector sum of two signals - direct and reflected from the ground, which leads to the law ≈1 / r ² (Vedensky’s formula) and to the “petal” radiation pattern of the transmitting antenna (see / G. Grudinskaya, Radio Wave Propagation, -2nd ed., Revised and additional - M.: Higher school, 1975.- 236 p. /). The radiation pattern of a transmitting antenna mounted at a height of 3 wavelengths above the surface of the dielectric is shown in FIG. 34. It is fundamentally important that the front of a “direct” pulse is not subject to fading, unless there are reflecting surfaces (except earth) at a distance of 3-5 m from the subscriber, since in this case the signals reflected from local objects have a longer duration than the front (< 10 ns) delay. From what has been said, a simple way of estimating the signal amplitude follows - to estimate the signal amplitude, the pulse front should be analyzed.

Consider FIG. 35. The figure shows the oscillatory circuit LCR, detector D and the differentiating circuit R ₁ C ₁ .

Let the voltage U = U ₀ sin (ωt) shown in FIG. 1 be applied to the antenna of the oscillating circuit (point 1) at time t = 0. 36. The amplitude of the voltage across the capacitor of the circuit (point 2) grows according to the law (1-exp (-t • ω / (2 • Q))) • Q • U ₀ , where Q is the quality factor. The voltage at point 2 is shown in FIG. 37. It can be shown that if a quadratic detector is used, the maximum value of the time derivative of the video signal is proportional to U $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ • Q • ω and is reached at time ≈ (Q / π) • T, where T = 2π / ω. The voltage at the output of the differentiating chain (point 3) is shown in FIG. 38. FIG. 36-38 are constructed for Q = 10. Thus, having determined the maximum value of the derivative of the video signal with respect to time, we obtain an estimate of the stationary amplitude of the signal on the circuit, which would have occurred in the absence of multipath distortions.

 To apply the method under consideration, it is necessary to ensure a high slew rate of the signal amplitude at the transmitter output (see Fig. 39.40). To accurately determine the time of arrival of the signal to the receiving device, it is desirable to have a low value of the quality factor of the oscillatory circuit. For example, with Q = 10, the maximum amplitude value is reached after approximately 3 periods of the carrier frequency. Accordingly, it is necessary to provide significant transmitter power with a small average distance between the transmitter and the receiver, so that the energy transmitted over 3 periods is sufficient for stable operation of the receiver.

If the pulses are selected according to the maximum value of the derivative, the effects associated with multipath propagation are minimized, in particular, if the maximum value is used to estimate the signal amplitude, the pulse in FIG. 32 extends selection threshold U _- due to "cap" formed by adding together a plurality of echoes, for accidental reasons having similar phase. The probability that the “cap” will have a section with a high slope (pulse in Fig. 33) is small, since in this case the reflected signals forming the “cap” should not only be phased, but arrive at the receiving device at the same time. If not the amplitude value, but the time derivative of the amplitude is used as the selection threshold, the pulse in FIG. 32 will not pass the selection threshold.

 The approach outlined has another major advantage. Suppose that a “useful” signal with a steep edge and a noise having a slowly varying complex amplitude are simultaneously input to the input of the receiving device. Such interference includes, for example, any FM signal with a standard bandwidth (≈0.01). It can be shown that when using the above method of pulse selection and amplitude estimation, the presence of such interference leads only to small errors in estimating the amplitude of the useful signal. Accordingly, the actual frequency band allocated to the system may already be the pass band of the receivers. If narrow-band radio channels fall into the passband of the receiving devices, this does not lead to disturbances in the system.

 In addition, the described method provides a high level of noise immunity. Indeed, an unmodulated carrier cannot be used as masking interference. If the carrier is modulated by a high-frequency signal, then the coordinates of the interference maker can be determined with a high degree of accuracy (provided that the receiving devices and the DS have the appropriate software).

It follows from the foregoing that if the radiation patterns of the receiving and transmitting antennas were spherical, then with the proposed method for estimating the amplitude, it could be argued that the amplitude of the “direct” signal decreases as the subscriber moves away from the receiver according to the law ≈ 1 / r ² , where r is the distance between the subscriber and the receiver.

Actually, the radiation patterns of the receiving and transmitting antennas are different from spherical ones. In addition, there is some slight likelihood that the reflected signals from a subscriber located outside the line of sight from the side of the receiving device in question, propagating along various "multi-tracks", will arrive at the receiving device at the same time, which will lead to an increase in the signal amplitude. For these reasons, we will further consider the following model: if the subscriber is in the zone of responsibility of the receiving device, then the amplitude of his signal depends on the distance as const / r ² , if the subscriber is outside the zone of responsibility, the signal of such a subscriber decreases according to the law s x const / r ² , where s> 1. In other words, we are considering the worst case scenario - signals from the zone of responsibility "fall" into the minimum of the radiation pattern, while "extra" signals receive additional amplification s times.

 Estimates show that s <3. Accordingly, at a point remote from the transmitter by a distance of 3 x R, we have at least three lower amplitudes than at a distance R from the transmitter.

Further, the value of 3 x R _max , where R _max is the distance between the receiving device in question and the point of responsibility zone as far as possible from it, will be called the radius of the conflict zone. Accordingly, a region of space located inside a sphere of radius 3 x R _max centered at the location of the antenna of the receiving device will be called a conflict zone.

 The number of samples that can be transmitted to the CA per unit time is limited by the bandwidth of the communication link connecting the receiver to the CA. If a dedicated telephone line is used for communication with the central station (see clause 3.5), the data transfer rate is limited to 64 Kbps. We will reserve 50% of the line capacity for solving the tasks specified in clause 1 - to ensure effective two-way wired communication between external devices connected to the receiving devices and the CA. Then, with a subscriber message duration of 100 bits, each receiving device can transmit to the CA ≈ 300 samples / s. It will be seen from what follows that such a stream of samples exceeds the actually necessary one, calculated on the basis of estimates of the maximum possible number of subscribers in the vicinity of the receiving device.

 Suppose that the selection threshold is set in such a way that the receiving device sends exactly 300 samples to the CA every second. Obviously, these samples will correspond to signals having the maximum amplitude among the set of all signals received at the receiving device.

соответственно, сигналы от абонентов вне рассматриваемой области не могут "вытеснить" сигналы из зоны ответственности приемного устройства. Сигналы абонентов, попадающих в зону ответственности приемного устройства, заведомо войдут в число сигналов, проходящих порог селекции приемного устройства.Let us first consider the option when a section of the transport highway with extremely high traffic intensity falls into the zone of responsibility of the receiving device - see Fig. 41. Assume that the receiving devices are evenly spaced along the specified line with an interval of 50 m. Neglecting the width of the line, the height of the antennas of the receiving devices, as well as the flow of messages from subscribers outside the line. Assume also that 12 direct signals are sufficient to determine the coordinates of the software. Under these conditions, for any point on the highway R ₁₂ <150 m and 300 m of the highway falls into the zone of responsibility of each receiver (the figure shows the zone of responsibility of receiver 1 by double hatching). Let the traffic on the highway take place in 6 rows in each direction and 10 linear meters of a row for each car — then the linear density of cars is 1200 km ^-1 . If each car on the highway under consideration is equipped with an HC and transmits IR once every ten seconds, then within our model it should be assumed that the receiving device 1 receives signals from all cars falling into an area of 2500 m long (this region contains 3000 cars). Consider the boundary of this region. Let us compare the amplitudes of the signals coming from a car located on the border of the zone of responsibility of the receiving device 1 (point 2) and a car located on the border of the region. The signal amplitude ratio is

accordingly, signals from subscribers outside the considered area cannot “squeeze” the signals out of the zone of responsibility of the receiving device. The signals of subscribers falling into the zone of responsibility of the receiving device will certainly be among the signals passing the selection threshold of the receiving device.

Obviously, if we receive messages from all subscribers in the conflict zone, i.e. remote from the receiving device under consideration at a distance of no more than 450 m (ordinary hatching), we certainly will not lose the messages of subscribers from the zone of responsibility of the receiving device 1, since the amplitude of the message of the subscriber located on the border of the zone of responsibility (point 2) is at least three exceeds the amplitude of the message of the subscriber located on the border of the conflict zone (point 3). There are no more than 1080 cars on the 900-meter-long section of the highway, transmitting an average of 108 messages per second. If the receiving device from the set of all signals arriving at its input every second will select 108 having the maximum amplitude, then the number of selected signals will certainly include signals coming from its area of responsibility. (An average of 36 signals come from the area of responsibility.)
Similar evaluations can also be made for a receiver that is remote from busy bus lines. We carry out the estimates for the example considered in Section 3.3, see Fig. 10. For each point of the area of the city territory shown in this figure, the inequality R ₁₂ <120 m. Accordingly, the "radius" of the zone of responsibility for each receiving device does not exceed 120 m. If we assume that 2 • 10 ⁶ cars are distributed throughout the city As the Punch field of points, an average of ≈ 120 cars falls into the zone of responsibility of each receiving device. On average, ≈ 1000 cars fall into the conflict zone, i.e. it is necessary to transmit to the CS≈100 samples / s.

A similar estimate for the subscribers of the first group leads to a negligible intensity of the sample stream (at the level of 10 ^-4 s ^-1 ).

 Our task is to establish for each receiving device a certain “optimal” selection threshold, at which the probability of losing a message from a subscriber in the area of responsibility would not exceed a predetermined one, and at the same time, the number of “extra” samples transmitted to CA, it would be minimal.

In principle, the following approach is possible - for each receiving device, an inspection of the served territory is carried out, its area of responsibility is determined, the conflict zone and the maximum possible intensity of the message flow I _max from subscribers falling into the conflict zone are determined, after which a selection threshold is established at which the receiving the device per unit time will receive no less than I _max messages.

 However, there is a much simpler and more efficient way to optimally select a selection threshold.

 Indeed, let the intensity of the stream of samples transmitted by each receiving device to the CA be determined by the commands of the CA, i.e. between the CA and each receiving device established two-way communication.

 In accordance with the commands of the CA, each receiving device automatically sets such a selection threshold at which the number of samples sent to the CA during the clock cycle of the receiving device (see clause 3.5) is equal to the specified one. In addition, the receiving device determines the amplitude of the signals passing the selection threshold, sorts the signals received during the time cycle in decreasing order of their amplitude, and sets each signal in its number in the resulting array.

 For each reference received at the DS, it is determined whether the given reference corresponds to an event that occurred in the zone of responsibility of the given receiving device, for which all coordinates received from different receiving devices, but having the same IR, use the method for determining the coordinates described in Section 3.2. In this case, the coordinates of the subscriber are determined and the samples corresponding to direct rays are set. If the countdown sent by this receiving device corresponds to a direct beam, and, in addition, the specified receiving device is included in the number K 'of “direct” devices closest to the subscriber, then this counting corresponds to an event that occurred in the zone of responsibility of this receiving device.

 Consider a random variable - the maximum number of the signal received from the zone of responsibility of a given receiving device during a given clock cycle (i.e., the signal having the smallest amplitude among all signals coming from the zone of responsibility of a receiving device during a clock cycle is considered). For this random variable during the system operation, an empirical distribution function can be easily constructed that will allow us to establish the optimal stream of samples transmitted to the DS for this receiver. Indeed, considering this function, it is possible to determine the probability of losing a useful signal when reducing the "scheduled task" for receiving subscribers' messages set for this receiver. If the magnitude of the reduction in the probability of error-free reception of a subscriber’s message does not lead to a decrease in the availability coefficient below a predetermined level, the intensity of the stream of samples transmitted by this receiver is reduced by the command of the CA.

 We give estimates for the probability of error-free reception of a subscriber’s message by the receiving device P and for the system availability factor G, depending on the values of K, K 'and P.

Значения величин P и Г для K = 10, K' = 12, τ = 200×10^-6 с приведены в табл. 1 и 2.Let the I-stream of messages at the input of the receiver passing the selection threshold, and τ the duration of each message. The message of the considered subscriber from the zone of responsibility of the receiving device will be lost if, during the time interval 2τ, a message from some other subscriber arrives at the receiving device, the signal of which passes the selection threshold. Since we assume that the subscriber’s message flow is Punch, we have:
P = (1-2τ) ^I-1 , (1)
where the dimension [τ] = c, [I] = c ^-1 .
Obviously, the following relation holds:

The values of P and G for K = 10, K '= 12, τ = 200 × 10 ^-6 s are given in table. 1 and 2.

 From the above table. 1 and 2 of the estimates it follows that the "asynchronous" exchange protocol that we have proposed is quite suitable for solving the tasks set in paragraph 1. Nevertheless, we will consider some modification of the method described above.

 The idea of the method is that the subscriber has the right to start sending a message only on the condition that there are no other subscribers nearby who are already sending messages.

 It is assumed that the HCs are equipped with receiving devices with the same operating frequency as the receiving devices of MPRLS. HC receivers include means for conducting amplitude selection of received signals. The HC transmits a message only at the moment when there are no signals passing the selection threshold at the input of the receiving device. Obviously, with the optimal selection of the selection threshold, such an exchange protocol leads to a high probability of error-free reception of a message (see below).

 To select the optimal selection threshold, we suggest using a tracking device that sets the selection threshold in such a way that the number of signals received per unit time passing the selection threshold is equal to some fixed value.

 Consider a specific example.

Let τ = 200 × 10 ^-6 s, and the HC receiving device receives 1000 signals passing the selection threshold every second. We assume that the entire message flow is caused by subscribers of the second group, evenly scattered throughout the city. According to the assumptions made earlier, 1000 signals correspond to 10,000 subscribers, all of these subscribers being located in a circle with a radius of ≈ 1000 m, in the center of which is the considered subscriber. Due to the small radius of the conflict zone (≈ (300-500) m), the subscribers in the conflict zone will certainly fall into the number of subscribers that influence the decision of the HC to start sending a message. Thus, “almost” (see below) excludes the possibility of simultaneous transmission of messages by two subscribers who are in the conflict zone of this receiver.

Under the assumptions made, the probability that the HC will be able to start transmitting a message at an arbitrarily chosen time moment is 0.8 (since the total duration of all messages that pass the selection threshold for each second is 200 • 10 ^-6 • 1000 = 0.2 s). If the transmission of the message at some point in time was not possible due to the presence at the input of the receiving device of the HC signal passing the selection threshold, a retry will be made after a period of time ≈τ. It is easy to show that with a probability of 0.9997 the waiting time of the “free channel” does not exceed 5τ. To select the selection threshold, we could not set a fixed number of messages, as suggested above, but require the tracking device that determines the selection threshold to set this threshold at a level at which the total duration of messages received during the time step and passing the selection threshold , would constitute some fixed part of the duration of the time step.

The possibility of losing a message with such an exchange protocol is not completely ruled out, since the subscriber in question “learns” about the presence of another subscriber only after a period of time necessary for the signal to propagate from the second subscriber to the first. Since for us only subscribers located in the conflict zone are significant, the indicated period of time does not exceed θ = D / c, where D is the diameter of the conflict zone, and c is the speed of propagation of radio waves. Since D <1000 m for almost any part of the urban territory, we assume that θ ≈ 3 × 10 ^-6 . Accordingly, the probability of error-free reception of a message at a maximum sample stream (I = 300) is:
P = (1 - 3 • 10 ^-6 ) ³⁰⁰ ≈0.999 (3)
There is another simple way to increase the likelihood of error-free reception for subscribers who have high requirements for the system availability factor. Namely, the subscribers of the 1st group should be equipped with more powerful transmitters than the subscribers of the 2nd group, while the receiving device should simultaneously receive two messages passing the selection threshold and having significantly different amplitudes at its input, should ignore the message with a lower amplitude and transmit to the CA a message with a larger amplitude.

 Options for the technical implementation of the proposed methods for organizing information exchange are discussed in clause 3.5.

 Previously, we did not consider the issue of the coverage area of the CA. We assumed that there was one CA in the city. However, the concept of "city" is rather arbitrary, because, for example, the cities of Moscow and Khimki do not have an externally distinguishable border and use common communications. Apparently, the most rational approach is that the coverage area of each CA strictly corresponds to the administrative boundaries of the territorial entity. However, in this case, problems may arise in determining the coordinates of the software located near the boundary of two or more coverage areas, since only a part of the direct signals of the software will arrive at each of the central points. Fundamentally, the solution to this problem lies in the fact that receiving devices located near the border of several coverage zones transmit the received samples simultaneously to all interested CAs. Technical details are outlined in clause 3.5.

3.5 SYSTEM OF RADIO COMMUNICATION OF SUBSCRIBERS WITH THE CENTRAL STATION WITH IDENTIFICATION OF SUBSCRIBERS AND DETERMINATION OF THEIR LOCATION. PREFERRED EMBODIMENT
According to the present invention, a city multifunctional radio communication system of a subscriber with a central station (CA) with identification of a subscriber and determining his location in a preferred embodiment consists of the following elements:
1. The set of transmitting devices (C), which are equipped with subscribers of the system (15.16);
2. The set of receiving devices that are equipped with all the buildings of the served territory according to the method described in clause 3.1 (1);
3. Means ensuring the presence of time stamp sequences on the receiving devices (14);
4. Many hubs 9 installed in substations of the urban telephone network;
5. Many dedicated telephone lines 8, each of which connects one or more receiving devices with one of the hub, and the connection between the concentrator and each of the receiving devices is bi-directional;
6. A certain number of CA 11, each of which has a certain coverage area. All CAs are connected to each other by communication lines 10. Each hub is connected to one or more CAs by fiber-optic or microwave lines and the connection between the concentrator and the CA is bi-directional;
7. Tools for determining the coordinates of receiving devices during deployment of the system (13);
8. A certain number of users of the system 12, each of which has a communication line with the CA.

 A schematic view of the device is shown in FIG. 1, a functional diagram is shown in FIG. 2.

 The system receives radio messages from subscribers and a sequence of time stamps. Each subscriber of the system has a unique identification code stored in the read-only memory (ROM) of the HC and which is part of the subscriber’s message. Subscribers transmit messages asynchronously, at previously unknown points in time (see clause 3.4). Receiving devices have means for determining the amplitude of messages, conducting selection and determining the time of arrival of messages. The selection threshold is set by the receiving device in such a way that the flow of messages passing the selection threshold is equal to the set established by the CA commands set for this receiving device. The message received from the subscriber, an estimate of its amplitude, the time it arrives at the receiving device (countdown), is transmitted to the concentrator via a dedicated telephone line.

 The concentrator adds to the readout the number of the receiving device, by the number of the receiving device determines the CA, the coverage area of which the given receiving device serves, and transmits the sample to the CA. If the receiving device is located near the border of the coverage areas of several CAs, then the reading of the receiving device is transmitted to all interested CAs. The correspondence between the numbers of the receiving devices and the destination CA is established by the commands of the CA to the hub.

 The subscriber’s identification is performed on the CA, if necessary, its coordinates are determined (see clause 3.2) and the final recipient of information (user) is determined, to which the subscriber’s message, data and coordinates are transmitted via the communication line.

 Simultaneously with the determination of the coordinates on the CA, receiving devices are tested, faulty receiving devices are determined, and for each operational receiving device, the optimal sample stream intensity is established, for which the CA generates commands and transmits them to the receiving devices.

 The receiving devices have connectors for connecting various external devices, for example, a traffic light, a device for servicing credit cards, which creates an effective two-way wired communication system between external devices and the CA.

3.5.1 CENTRAL STATION CALL DEVICE
In a preferred embodiment of the invention, all subscribers of the system transmit radio messages in the same frequency range.

 A possible solution would be to use a sequence of short (≈1-10 ns) square-wave pulses without RF filling as shown in FIG. 42, see / Harmut H.F. Nonsinusoidal waves in radar and radio communications. Per. from English M.: Mir, 1985.- 376 pp., Harmut X. F. Theory of sequential analysis: fundamentals and applications. Per. from English - M .: Mir, 1980.- 575 p. /. However, such a technique is currently not generally accepted, and further, when setting out the embodiments of the invention, we will focus on traditional technical solutions.

 Further, we will assume that the message is encoded in a positional binary system; see FIG. 43, moreover, a wave train corresponds to unity, and a pause corresponds to zero. The carrier frequency is ≈ 1 GHz. We assume that the message always starts with one and does not contain more than 4 zero bits in a row. The duration of the wave train is selected based on the width of the frequency band allocated for the shock wave, and can be from 10 to 100 ns. Note that the use of “short” (of the order of 10 ns) trains is hardly advisable, since it requires the allocation of a wide frequency band and does not really lead to an increase in the accuracy of determining the signal arrival time to the receiving device due to the increase in the pulse duration during its propagation in the city. It is wiser to use longer wave trains, “shortening” them at the receiving stage, as proposed in Section 3.4.

 Since the pulse front is of interest to us, it is necessary to ensure a rectangular envelope shape at the output of the transmitter by appropriate circuitry solutions. Thus, the waveform at the output of the transmitter shown in FIG. 40 is unacceptable to us, unlike the waveform shown in FIG. 39. Such a waveform will take place, for example, if the capacitor of the oscillatory circuit of the transmitter output stage is pre-charged before transmitting the wave train, or if a broadband amplifier is used as the transmitter power amplifier (see, for example / High-power field circuitry transistors: Reference book / V.V. Bachurin, V. Ya. Vaksenburg, V.P. Dyakonov and others. Edited by V.P. Dyakonov. - M.: Radio and communications, 1994.-280 p. /). The frequency band occupied by the pulse mainly depends on the pulse duration and weakly depends on the shape of the envelope.

 The shock wave in its simplest form is shown in FIG. 44.

ROM contains a unique identification code of the subscriber. Sensors D ₁ - D _n can be activated either manually or automatically. The sensor can operate periodically with a predetermined period. The pickup can be a receiver that receives radio commands. The radio command contains the IR of the destination subscriber, and the sensor is triggered when the IR of the subscriber coincides with the IR stored in the ROM. The MP establishes the fact of the triggering of the sensors, generates a subscriber message, consisting of IR and the numbers of triggered sensors, and controls the operation of the transmitter.

 HC is preferably shown in FIG. 45. In accordance with the method described in clause 3.4 to ensure a high level of probability of error-free reception of a message, the HC has a receiving channel with the same operating frequency as the transmitter.

When the sensor is triggered, the MP executes the program for selecting the optimal selection threshold. The receiving channel of the HC (positions 32-41) is completely similar to the receiving channel of the receiving device MPRLS (see clause 3.5.2). The fact that a subscriber’s message passes the selection threshold is established by the following algorithm: after a single bit is detected that passes the selection threshold, the MP waits for the appearance of the next single bit for the time necessary to transmit 5 bits (10 • 10 ^-6 s) . If during the specified time a single bit passing the selection threshold has not been received at the input of the receiving device, the MP considers that at the moment there is no message passing the selection threshold at the input of the receiving device. The number of messages is calculated as follows: the time interval between the moment of receipt of a single bit passing the selection threshold and the nearest 5-bit pause is determined. If the duration of the interval exceeds the duration of the message (200 • 10 ^-6 s), then the number of messages is determined as the quotient of the indicated values. Otherwise, the MP considers that one message has arrived at the indicated time interval.

 The MP selects some initial value of the selection threshold (for example, the optimal value of the selection threshold obtained during the previous transmission of the message) and determines the number of messages of subscribers passing the selection threshold over a fixed time cycle (for example, within 100 ms). If the indicated number is close to the given one (for example, it is in the range from 100 to 300), the current value is selected as the selection threshold. If the number of messages passing the selection threshold is different from the given one, the MP, using the feedback principle, determines the optimal threshold value over several clock cycles.

 After the optimal selection threshold is established, the MP initiates the transmitter when there is no message passing the selection threshold at the input of the receiving device.

 Depending on the purpose, hydrocarbons may have design features, discussed below.

 1. HC for the protection of an individual.

 The HC operates in a pulsed mode with a high duty cycle, so even with a pulsed power of 100 W, two AAA batteries are enough to power the HC. Accordingly, the HC can easily be made small-sized (mass ≤50 grams).

 In the usual version, the HC has sensors that are manually actuated, that is, it has buttons for calling emergency services - fire protection, police and ambulance. When triggered, the HC transmits a radio message repeatedly, for a time sufficient for the arrival of an emergency patrol with an interval, for example, of one second. The indicated time for the conditions of Moscow does not exceed one or two minutes, provided that 500 emergency patrol vehicles are simultaneously located on the territory of the city and each of these vehicles is a subscriber of the system in question. Repeated repetition of the message will allow the emergency forces duty officer to "direct" the patrol car to the call point in real time, taking into account changes in the coordinates of the caller.

 The HC should be equipped with a device that changes its state when the HC is brought into action - a mechanical seal or an appropriate electronic circuit. In this case, the person who unjustifiably called the emergency service can easily be held accountable.

 The HC can be additionally equipped with a built-in microphone and a small-sized tape recorder, automatically activated when a police call. In this case, an evidence base is created for the disclosure of crimes such as threats and extortion.

 Special versions of the HC are possible, in which the HC is triggered automatically. In this case, an individual places sensors on his body that measure parameters such as heart rate, pressure, skin moisture, etc. If these parameters change sharply as a result of an attack of an illness, injury, injury, death, or even severe fright, an emergency call services.

 2. HC for car security.

 With significant transmitter power, the HC transmission antenna can be located almost anywhere in the car or even under its bottom. Due to the small average power consumption, the HC can have an autonomous energy source. The HC sensors must be triggered when they get into the car, tow it, start the engine, or start driving. The HC can be equipped with manual call buttons for emergency services - fire, police, ambulance, state automobile inspection. The HC can have a channel for receiving radio commands and operate on a radio command.

 3. HC for tracking the car.

 In the simplest case, the HC is triggered periodically, with a predetermined period. With each operation, a single IR transmission occurs.

 If the HC is used to track emergency patrol cars or taxi cars, the HC can have a radio command receiver and change the transmission period of the IR when a corresponding command is received. Typically, these vehicles have radiotelephone channels of communication with the dispatcher. If you use the same channels for transmitting radio commands, in reality the traffic of these channels will not grow, but decrease, because the time required for the driver to transmit information about his coordinates in the dialogue mode with the dispatcher is many times greater than the time required for the transmission of the radio command.

 The HC can also be equipped with a switch that defines the information message. For example, the HC of a taxi car can transmit the message “Available,” “Busy,” “Not working.”

 In some cases, it may be appropriate to carry out an HC with an easily removable (replaceable) ROM. In this case, when accepting the shift, the car driver inserts the ROM containing his personal code into the HC connector. With this approach, it simplifies the solution of issues of accounting for the driver’s working time and control of his discipline.

3.5.2 MRLS RECEIVERS
In paragraph 3.1, the question of the location of the receiving devices of MPRLS (stations) was considered. Section 3.4 discusses a method for estimating the amplitude of subscriber messages and methods for conducting selection. For each message received at the station and passed the selection threshold, it is necessary to determine the time of its arrival. In principle, the following methods for solving this problem are possible:
1. All receiving devices are equipped with ultra-precise watches;
2. On the communication line connecting the receiving device with the hub, the receiving device receives a sequence of synchronizing pulses;
3. A radio frequency channel is used to transmit synchronizing pulses, for which purpose one or more transmitters of synchronizing pulses are installed on the territory of the city.

 4. A radio frequency channel is used to transmit synchronizing pulses, and the synchronizing pulse transmitter is located on a geostationary artificial earth satellite.

 The first method is not acceptable due to the high cost and low reliability, the second method is possible if an optical fiber or microwave line is used to connect the receiving devices to the hub. In this case, the concentrator can be equipped with a stable generator and means for periodically determining the propagation time of the signal from the concentrator to the station (the indicated time is an unstable value and depends, in particular, on the temperature of the communication line). The disadvantage of the 3rd method is that it does not provide for a significant number of receiving devices the direct visibility of the transmitter antenna. It is known from practice that a collective television antenna is often outside the line of sight from the antennas of the television center repeater and it has to be tuned to receive a signal reflected from nearby buildings. In this case, it is possible to achieve reliable and stable signal reception, however, the signal arrives at the antenna with some delay. It is important that the indicated delay is stable and may not change for years, unless a new building is built near the antenna or the old one is destroyed. Accordingly, if the transmitter of the synchronizing pulses is placed on the mast of the television program repeater, use an antenna with a narrow radiation pattern as the receiving antenna, carefully configure it and periodically measure the time delay of the signal, then within the considered method, acceptable results can be achieved.

 Further, as a preferred option, we will consider the 4th method, since with the satellite position close to the zenith, it provides direct visibility of the transmitting antenna, and, accordingly, the most stable reception conditions. In addition, this method does not require skilled labor when installing receiving antennas. Although the propagation delay of the signal is an unstable value depending on the state of the ionosphere, it is significant that within the virtual zone, due to its small size (D <300 m), the delay value is almost the same for all stations and, accordingly, does not affect the accuracy determination of coordinates (see clause 3.2).

 The repetition period of synchronizing signals is supported with a high degree of accuracy. For definiteness, we assume that the duration of each signal is 100 ns, and the repetition period is 10 μs ± 0.01%. We will also assume that in addition to the indicated sequence, the transmitter emits a sequence of signals phase-shifted by 5 μs relative to the first and having a repetition period of 100 ms. This sequence is necessary for synchronization of information exchange between the station and the hub (see clause 3.5.3). Further, each time interval starting with the arrival of a pulse of the second sequence is called the clock of the receiving device.

 The 1st and 2nd sequence clocks are shown in FIG. 46.

 A functional diagram of an MPRL receiver is shown in FIG. 47.

 The channel of synchronizing pulses consists of an antenna 42, receiver 43, GTI 44 and counter 45. The GTI is designed to convert a sequence of synchronizing signals into a sequence of short video pulses with a high steepness of the edges. The phases of both sequences are tightly coupled to each other. There are many technical solutions that allow you to perform the specified conversion. Since these technical solutions are well developed and well known, we will not discuss them here.

 The GTI is synchronized with the above sequence of video pulses as shown in FIG. 48. Since the repetition period of synchronizing signals is maintained with a high degree of accuracy, the repetition period of clock pulses is known with a high degree of accuracy. Clock pulses are used to synchronize the microprocessor and determine the time of receipt of messages from subscribers. Clock pulses are counted by the counter 45. The counter is reset to zero with the arrival of each synchronizing video pulse of the second sequence (that is, every 100 ms). At the MP command, the counter value can be rewritten into the MP memory.

 The channel for receiving messages from subscribers consists of an antenna 32, a broadband high-frequency amplifier 33, a detector 34, a video amplifier 35, a differentiating chain 36.

 The maximum amplitude of the video pulses at the output of the differentiating chain is a monotonic function of the signal amplitude. The amplitude of the signals passing the selection threshold can have a spread within 4-6 orders of magnitude. Accordingly, to obtain an estimate of the amplitude in digital form, it is necessary either to use the ADC 38 with a large number of bits (≈20), or to prologarithm the signal coming from the chain 36. The second method is preferable. For the logarithm of the signal, a logarithmic amplifier 41 is used.

 The selection threshold in digital form is set by the microprocessor. To obtain the selection threshold in analog form, DAC 37 is used.

 To select the signals, a comparator 39 was used. The selection threshold from the output of the DAC 37 is fed to the inverting input of the comparator. A prologarithmic pulse from circuit 36 is received at the second input. If the signal amplitude from amplifier 41 exceeds the selection threshold, the comparator output signal is high. The transition of the output signal of the comparator from low to high causes interruption of the MP. The interrupt service program, in particular, includes instructions for digitizing the maximum value of the derivative envelope. Digitization is performed when the comparator signal goes from high to low. At this moment, the MP activates the ADC 38. After the ADC is ready, the received data is read into the MP memory and the MP resets the circuit to determine the maximum value of 40.

 After the front of a single bit arriving, passing the selection threshold, the MP sets a new value for the selection threshold for the time the bit is transmitted (in our example, 2 μs). For example, the selection threshold can be set in such a way that a signal with any amplitude arriving earlier than 2 μs after the arrival of the edge is ignored. The selection threshold can also be set in such a way that interruption of the magnetic field occurs upon receipt of a signal whose amplitude is a predetermined number of times (for example, 3 times) greater than the amplitude of the signal received during the previous 2 μs. With this method, from two different messages of subscribers having a significantly different amplitude and arriving at the receiving device at the same time, a message with a larger amplitude can be isolated and transmitted to the CA (see clause 3.4).

 In general, the MP operation algorithm is as follows.

 For each station, the CA commands establish the number of subscriber messages that must pass the selection threshold during the cycle (in our example within 100 ms), and for each message that passes the selection threshold, the time of its arrival at the station must be determined and its amplitude estimated . Obviously, messages passing a certain selection threshold have a maximum amplitude among all messages that, in principle, could be received by the station at any lower selection level.

 The indicated “planned” number of messages is stored in the memory of the MP (information exchange between the station, the concentrator, and the CA is discussed in Section 3.5.3). The MP counts the number of messages that pass the selection threshold, and constantly adjusts the selection threshold so that the number of messages that pass the selection threshold during a cycle exceeds a predetermined one, for example, by 20%. Reception of a larger number of messages than would be required according to the CA command is due to the fact that, at any selection threshold, the number of messages arriving during a clock cycle is a random variable with a certain statistical spread. Before sending received messages to the CA, the "extra" messages that have the smallest amplitude among all received messages will be eliminated (see below).

Simultaneously with the receipt of the message, the time of its arrival is determined and its amplitude is estimated in some arbitrary units (the logarithm of a quantity having a dimension of B ² / s and multiplied by some dimensionless coefficient different for different receiving devices).

Message arrival time is determined as follows:
1. Upon receipt of each single bit that passes the selection threshold, the MP is interrupted. MP reads the current value of counter 45 and multiplies it by the repetition period of clock pulses, i.e. for each single bit, the time of its arrival at the station is set, and the time line is counted as the moment the second sequence arrives at the station of a synchronizing pulse.

 2. After the completion of the receipt of the message (the message is considered completed if 5 zero bits are received in a row), the time of receipt of the message is estimated. As the indicated estimate, the sum of the arrival times of all unit bits of the message divided by the number of unit bits in the message is used.

 With this method of estimating the time of receipt of a message at the station, we determine the time of arrival of the first single bit at the receiver plus some time interval that is the same for all receivers that have received the message in question.

где Δt_1i - - интервал времени между 1-ым и i-ым единичным битом,
K - число единичных бит в сообщении.Indeed, with this method, we determine the value:

where Δt _1i - is the time interval between the 1st and i-th unit bits,
K is the number of unit bits in the message.

 We do not require the HC to maintain time intervals between transmitted bits with a high degree of accuracy, since for any values of the indicated intervals, the second term on the right-hand side of (1) is the same for all receivers that have received the message. With our method of determining coordinates, the systematic error in determining the time, which is the same for all receiving devices, does not lead to an error in determining coordinates (see Section 3.2).

The advantage of the above method for determining the time of signal arrival at the station is that the value of t _{1 of} interest to us is determined by averaging K independent measurements, which significantly reduces the method error. In particular, we can measure the time of arrival of the signal with an error less than the repetition period of the clock pulses of the microprocessor. Estimates show that at a MT frequency of 100 MHz, the error of the method is ≈ 1 ns.

 The signal amplitude is estimated for each single bit of the message that passes the selection threshold. Multipath signal propagation does not lead to a difference in the amplitudes of the single bits that make up a single message (see § 3.4 remark 1). The difference in amplitudes is caused only by the presence of signals at the input of the receiving device that do not pass the selection threshold (noise). The selection threshold (or, equivalently, the “message reception plan”) can always be set in such a way that a useful signal with a given level of probability passes the selection threshold with a sufficient margin in amplitude (estimates in Section 3.4 are made under the assumption that the amplitude signal from the zone of responsibility at least three times the amplitude of the signal, "barely" passing the threshold of selection). Given the small spread in the amplitudes of individual pulses, one can propose many different procedures for averaging amplitudes that do not require complex calculations.

By the end of the station’s time cycle, messages received during the cycle, an estimate of the time of their arrival, and an estimate of their amplitude in arbitrary units are in the MP memory. The total number of these messages exceeds the “plan” set for this station. After completing the time cycle, the MP performs the following sequence of actions:
1. Considering the actual number of messages that have passed the selection threshold during a completed time cycle, the MP specifies the selection threshold that will be set during the current cycle;
2. Sorts messages in descending order of their amplitude;
3. Selects from these messages N with a maximum amplitude, where N is the "scheduled task" set for this station. Messages that are not in the specified N are ignored;
4. Each message is assigned its number in the sorted array, in particular, the message with the maximum amplitude receives number 1, and the message with the smallest - number N;
5. Of all the indicated information, N samples are generated, which are then transmitted via a dedicated telephone line to the hub (see clause 3.5.3). In a preferred embodiment, the samples are sorted, for example, in ascending order of the infrared subscriber, before being sent to the hub. Sorting the stream of samples directly to the CA (to allocate samples related to one event) is associated with significant computational overhead, since the time needed for sorting grows as the square of the number of samples. The load on the CA is significantly reduced if the sorting is performed by receiving devices and hubs.

 We emphasize that during the execution of the above actions, the MP carries out the reception of messages, “detaching” from the execution of the above algorithm for the time of servicing interruptions that occur when signals are received that pass the selection threshold.

 The functional purpose of the station is to receive messages from subscribers, extract N of them with the largest amplitude, generate samples and send these samples to the hub. In addition, the station receives commands coming to it from the CA through the hub, determining the value of N, and serves two-way information exchange between external devices connected to the station, and the CA through the hub. In addition, CA teams can put the station into an operating mode different from the standard one, for example, to determine the station coordinates during system deployment or to determine the coordinates of the masking jammer.

The station count consists of the following fields:
1. Subscriber message;
2. Estimation of the time of receipt of the message;
3. The relative amplitude of the message, ie serial number of the message in the array, consisting of all messages transmitted to the CA during the clock cycle and sorted by the amplitude of the messages in arbitrary units;
4. The checksum of the reference for reliability control when transmitting the reference over the communication line;
5. The concentrator adds to the sample field containing the number of the receiving device.

Let us dwell on the preferred design solutions and technical requirements for MPRLS receiving devices:
1. The station must withstand a long period of operation in conditions not protected from environmental influences;
2. The station should not have its own source of secondary power supply, but mainly be fed from the communication line connecting it to the hub;
3. In case of breakage or unauthorized access to the communication line between the station and the concentrator, an alarm signal must be generated that is transmitted to emergency services for response;
4. When installing and replacing the station, qualified labor should not be used. All stations must be interchangeable;
5. The station should have low cost, weight and dimensions.

 In a preferred embodiment, the station is mounted on a printed circuit board and poured into the compound. Antennas for HC and synchronization channels are attached directly to the circuit board. The station has two two-wire lines - one for connecting to a dedicated telephone line and the second for connecting external devices. In the vast majority of cases, stations are located away from busy traffic routes, so it may be wise to connect several stations to one dedicated telephone line. In this case, simple matching devices are required, each of which has several connectors for connecting stations and one connector for connecting a dedicated telephone line. The appearance of the station and the method of its mounting on the roof of the building are shown in FIG. 49, 8, 9.

 The low cost of the station is due to the absence in its composition of any precision devices (with the possible exception of the receiver of synchronizing pulses). Indeed, the GTI is synchronized once every 10 μs, and the variation of such instability factors as the supply voltage and temperature during the indicated time can be neglected. Devices evaluating the amplitude of messages and conducting their selection should have a small drift for 100 ms. There are also no excessive requirements for the microprocessor - it was previously shown that when using the appropriate methods, the error of the method for determining the message arrival time below the repetition period of clock pulses, which allows the use of MP with a low clock frequency - is really at the level of 30-50 MHz. In addition, the MP operation algorithm does not require the use of floating-point operations. With that said, in mass production, the cost of the station does not seem to exceed $ (10-15) in 1996 prices.

 In conclusion, we consider the question of determining the coordinates of the receiving devices and the time delays of the synchronizing pulses relative to the "true" time scale. The indicated delays are different for different stations, because they depend on the mutual coordinates of the transmitter and receiver of the clock pulses and, in the case of "ground" based transmitter, on the actual length of the optical path of the signal, taking into account all reflections.

 Even if we assume that the coordinates of all buildings in the city are known with a sufficient degree of accuracy (at the level of fractions of a meter), then “linking” the coordinates of each receiver to the coordinates of the building is a difficult task due to the need for careful measurements of the coordinates of the receiver relative to the reference points buildings and giant workflow. In addition, this method does not allow direct measurements to determine the above delay value. If the clock transmitter is located on a geostationary satellite, the delay can in principle be determined theoretically. However, this theoretical value does not take into account delays in the receiving channel, which may be different for different stations. If the transmitter is “ground-based”, a theoretical determination of the delays is in principle impossible.

 The preferred solution to this problem is to use radar methods to determine the coordinates of stations. A method for determining station coordinates and time delays is shown in FIG. 50.

Let the helicopter 13 sequentially “freeze” at several points whose coordinates are known with a high degree of accuracy. The indicated points are selected so that in direct line of sight from each receiving device, the coordinates of which are determined, there are at least 4 points. The helicopter is equipped with a transmitter operating in the range of either HC or in the range of a clock transmitter, and a clock receiver. After the helicopter “hovered” at a given point, it transmits a single bit. The bit is transmitted synchronously with the arrival of a clock pulse. The clock pulses arrive at the receiver with a delay equal to the propagation time of the signal from the clock transmitter to the receiver. Since the coordinates of the helicopter and the transmitter of synchronizing pulses are known with a high degree of accuracy, corrections can easily be made to bring the moment of transmission of a single bit to the “true” time scale. We assume that a single bit is transmitted at time t ₀ . Let the helicopter sequentially transmit unit bits from points 1,2,3,4 each time at time t ₀ . The indicated points are in the line of sight from the side of the receiving device 1. The signals of the transmitter are transmitted to the receiving device 1, respectively, at time t ₁ , t ₂ , t ₃ , t ₄ .

 The indicated times are measured each time with a systematic error Δ equal to the delay in receipt of a synchronizing pulse at the receiving device. Due to the reversibility of the ray path (we conventionally assume that there are receivers at points 1,2,3,4, and at point 1), the method described in Section 3.2 can be used to determine the coordinates of receiver 1. Section 3.2 shows that the systematic error Δ, which is the same for all measurements, does not lead to an error in determining the coordinates. Having determined the coordinates of the receiving device, we can easily determine the delay Δ. .

 Note that it is reasonable to apply the method described in Section 3.2 in full to the problem under consideration, that is, to use more than 4 direct signals to determine the coordinates of the receiving device. In addition, the signal arrival time should be determined not by one bit, but by a significant (hundreds and thousands) number of unit bits. Applying the corresponding statistical procedures to all the data obtained, we can determine the coordinates of the software with a high degree of accuracy.

 Simple estimates show that for Moscow it is necessary to have ≈ 100 points with known coordinates. In this case, with a helicopter flight height of 3-4 thousand meters, direct visibility from each side of the MPRLS receiver will be guaranteed at least 10 such points.

 When receiving devices determine their own coordinates, receiving devices at the command of the CA are transferred to a special mode of operation. It is assumed that both the receiving devices and the CA have the appropriate software.

3.5.3 HUB
The concentrator is designed to organize two-way information exchange between the receiving devices of MPRLS and CA. In addition, in a preferred embodiment, the receiving device is powered over a dedicated telephone line, i.e. the hub is a secondary power source for receiving devices. The hub also protects the communication line and receiver from unauthorized access.

 For definiteness, we assume that the hub serves 1000 receiving devices, each of which is associated with one or more of 16 CAs. The time interval of the receiving device is 100 ms (see clause 3.5.2).

 A functional diagram of the hub is shown in FIG. 51.

 RAM 51 consists of 2,000 blocks 49 and 50, each of which has a volume of ≈ 4 Kbytes. MP has random access to any byte of memory. An I / O port 48 is connected to each pair of blocks 49 and 50, which in turn is connected by a dedicated telephone line 8 to one of the many receiving devices of MPRLS. A modem 47 is used to communicate 48 with line 8. Each port 48 can, independently of the MP, either record data from the receiver to the block 49 allocated to this receiver, or independently read the data from block 50 and transmit the read data to receiving device. For communication with central stations, 16 microwave or fiber optic lines 10 are used.

 The first half of the time cycle is the transfer of data from the hub to the receiving devices on dedicated lines 8 and, at the same time, data is transmitted from the hub on lines 10 to the CA. It is assumed that the memory blocks 49 and 50 contain data recorded in them during the second half of the previous clock cycle. Data is transmitted to the receivers by ports 48 of blocks 50, regardless of the MP. In turn, the MP transmits data to the CA via lines 10. In clause 3.5.2, it was indicated that in the preferred embodiment, the samples coming from the receiving device are sorted by IR. Simultaneously with the transmission of data to the MP line, it merges the samples contained in blocks 49, i.e. MP transmits in line 10 a sorted stream of samples. In addition to the commands for the receiving devices, the CA transmits commands for the hub, which establish a connection between the numbers of the receiving devices and the numbers of the CA, in the coverage area of which this receiving device falls. These commands are stored in memory and allow the MP to select line 10 for transmission of samples. If the receiving device is located near the border of the coverage areas of several CAs, the readout of this receiving device is transmitted to all "interested" CAs, i.e. several lines 10 are selected for transmission.

 The second half of the time cycle transfers data from the stations to the hub via dedicated telephone lines and at the same time transfers data from the CA to the hub via line 10. Data received from the stations to the hub is recorded into memory blocks by 49 ports 48 in stand-alone mode without MP . In turn, the MP receives data received on line 10. This data can be commands for receiving devices or data for external devices connected to the receiving devices. In any case, the data received from the CA contains the number of the receiving device - the destination. By the number of the receiving device, the MP determines the memory unit 50, in which it places the data.

 There are many different technical solutions that allow you to use the communication line to power the receiving device. One such solution is shown in FIG. 52.

 It is assumed that modem 47 contains an isolation transformer 53. A constant supply voltage is connected to capacitor 56. Capacitors 56.57 close the information signal circuit. The figure also shows the isolation transformer 54 included in the modem of the receiving device. To power the modem and the entire receiving device, the constant voltage allocated to the zener diode 58 is used. It can be seen from the figure that line 8 is used both to transmit the signal and to power the receiving device.

 Since all receivers are synchronized, the phase of the signals transmitted to the hub can be maintained with high stability. The phase of the signals arriving at the hub depends on the wave properties of line 8. With unauthorized access to lines 8, the phase of the signals changes, which can be recognized by the phase comparator 55. In this case, the hub generates an alarm signal and transmits it to emergency services for response.

3.5.4 CENTRAL STATION
The central station is connected by communication lines to several hubs. For each of these communication lines, a sample stream is received sorted by the subscriber’s identification code. The CA merges the streams and selects samples related to one event (having the same IR), after which it identifies the subscriber and, if necessary, determines its coordinates. Based on the identification and determination of the coordinates of the subscriber, the CA determines the final recipient of the information (user). The CA also performs the function of optimal organization of the system - it identifies faulty receiving devices and determines the optimal selection threshold for each receiving device (or, what is also, the optimal sample stream transmitted by the receiving device).

 In general, the CA is a hardware-software complex. It is possible to use both universal computing equipment and specialized computing tools.

 To accomplish the tasks, the CA must have significant computing power, appropriate software and databases.

The CA works with the following databases:
1. Identification data of subscribers. The database allows you to set the subscriber's data on his IR. For example, if the subscriber of the system is a car calling an emergency service, its brand, color, state number should be set by IR. registration, owner data, etc.

 2. The coordinates of the receiving devices and the magnitude of the time delays in the arrival of clock pulses. The database is necessary for determining the coordinates of the software according to the method described in clause 3.2.

 3. Data allowing to determine the final recipient of information (user) by the coordinates of the subscriber and his message. For example, when calling emergency services by the number of the sensor subscriber that worked on the HC, the called emergency service is set, and according to the coordinates of the software, its territorial unit.

 4. Statistical data allowing to establish the optimal selection threshold (see clause 3.4) and establish faulty receiving devices (see clause 3.2). In addition, based on statistical data, the radius of the zone of responsibility of each receiving device is determined. The specified database is maintained for each receiving device. For each station that sent a count, it is established whether this count corresponds to an event that occurred in its area of responsibility. If this is the case, then the residual value and the relative amplitude of the message (see clause 3.4) are recorded in the corresponding file.

 The method for determining coordinates described in Section 3.2 can easily be reduced to an almost asynchronous solution of many problems, each of which refers to a separate point in space.

Indeed, consider the XOY coordinate system (all subsequent arguments can easily be generalized to the three-dimensional case). Consider a discrete set of points with coordinates X = x ₀ + iΔ, Y = y ₀ + kΔ, i, k = 0 ... L. Further, this set will be called a lattice with a period Δ, and each of the points of the set will be a lattice node. We assume that a rough estimate of the PO coordinates is known and the lattice covers the region of the possible position of the PO, i.e. the coordinates of the node (0,0) and the period Δ are set accordingly. To determine these parameters, sort the samples in ascending order of t _i , determine the coordinates of the node (0,0) so that the receiver corresponding to the smallest t _min = t _i is in the center of the grating, and choose Δ from the condition L / 2 × Δ> R _resp , where R _resp is the radius of the zone of responsibility (see clause 3.4) of the receiving device with the smallest t _i . The value of R _resp for each receiving device can initially be set with a margin, and then refined during the operation of the system (see below). From the sorted array to exclude samples for which t _i - t _min> R _holes that reduce computational costs and increase the accuracy of determining the coordinates (see section 3.3.). If as a result of the estimates a Δ value is obtained that is unacceptable for determining the coordinates with a given accuracy, the problem can be solved in two passes according to the scheme roughly.

 In relation to the tasks posed in paragraph 1, the z-coordinate of the software is not of interest. If the topography of the territory is known, then the z-coordinate of the software can be defined as a function of the x, y-coordinates of the software, since the antenna’s height above the earth’s surface h is usually known with sufficient accuracy (for example, for a car h≈2 m). Accordingly, the solution to the problem should be sought on the surface (x, y, φ (x, y) + h, where the function φ (x, y) describes the topography of the territory. Next, we assume that the function φ is known at each lattice point.

 In a preferred embodiment, to solve the problem of determining the coordinates should use a specialized computer (ST). A possible technical solution is shown in FIG. 53.

In FIG. 53, a matrix of (L + 1) x (L + 1) microprocessors (MP) 60 is shown. Each MP has a memory cell containing the “address” of the MP in the matrix. The address is a pair of numbers i, k, i, k = 0 ... L. Each MP is "responsible" for the lattice node with the coordinates X = x ₀ + iΔ, Y = y ₀ + kΔ, where (x ₀ , y ₀ ) the coordinates of the node (0,0). The characteristic value is L ≈100, Δ ≈ (3-10) m. Each has a built-in high-speed RAM (in reality, no more than 16 KB is needed). All MPs have a common data bus 62, a common interrupt line 63 and a synchronization line 64. Software is downloaded to all MPs when the power is turned on, all MPs are controlled when solving coordinate problems, all MPs are synchronized, and interrupt service is performed by the central processor (CPU) 61 .

To solve the problem of determining coordinates, the same data is loaded into all MPs:
1. The coordinates of the node (0,0) of the lattice and its period Δ;
2. The coordinates of all stations that sent samples (x _i , y _i , z _i ) i = 1 ... N;
3. The times of arrival of signals to all stations t _i , i = 1 ... N;
4. The number of “extra” signals l (see § 3.2, Remark 3).

 5. The expected number of direct signals K + 1.

 That is, 4N + 5 numbers are loaded into the memory of all MPs (actually, N ≈ 15-30). Data is downloaded to all MPs simultaneously, i.e. The CPU places the next input number on the data bus and initiates the interruption of all MPs. The programs of all MPs are the same. Each MP reads a number from the data bus and writes it to RAM. Since the values of the signal arrival times are determined with an accuracy no better than 10 ns, it is impractical to enter the coordinates of the receiving devices into the MP with an accuracy higher than 1 ns. Accordingly, all input data can be represented in integer format. If the size of the coverage area does not exceed 20 km, 16-bit numbers can be used.

 In the general case, it is necessary to add to the memory of each MP the value φ (x, y) + h for the corresponding lattice site. However, usually φ is a fairly smooth function and can be approximated by a small number of flat sections, for example, of a quadrangular shape. Each of these sections is completely defined by a set of 12 numbers. We can sequentially enter these sets into the memory of all MPs simultaneously and each MP can determine its own z-coordinate in stand-alone mode.

 After downloading all the data, the CPU initiates the execution by each MP of the program for calculating the likelihood function at the controlled point.

The operation algorithm of each MP is as follows:
1. MP calculates the coordinates of the control point (x, y, z).

3. МП сортирует величины Φ_i в порядке возрастания.2. MP calculates N quantities

3. MP sorts the values of Φ _i in increasing order.

5. МП последовательно исключает из массива невязок не более чем l первых элементов, в случае, если для этих элементов величина 1-ой условной невязки меньше -1.5σ. При исключении каждого элемента производится перерасчет t₀ согласно 4 (во всех формулах предполагается, что суммирование распространяется на первые K элементов массива, непосредственно следующих за исключенными).4. MP calculates the value

5. MP sequentially excludes from the array of residuals no more than l first elements, if for these elements the value of the first conditional residual is less than -1.5σ. When each element is excluded, t _{0 is} recalculated according to 4 (in all formulas it is assumed that the summation extends to the first K elements of the array immediately following the excluded ones).

После того, как все МП выполнили указанный выше алгоритм, необходимо установить МП, вычисливший наименьшее значение Λ . В качестве оценки для координат ПО следует выбрать подотчетный указанному МП узел решетки, а в качестве оценки для t₀ значение, вычисленное указанным МП. Простейшее решение состоит в последовательном опросе ЦП всех МП, однако в настоящее время известны гораздо более эффективные алгоритмы параллельной обработки информации. Например, можно использовать матрицу МП, организованную по принципу транспьютера. В этом случае МП обмениваются данными непосредственно друг с другом, не используя общую шину данных, за счет чего минимальный элемент может быть найден за небольшое число тактов.6. MP calculates the value

After all MPs have completed the above algorithm, it is necessary to establish the MP that has calculated the smallest value of Λ. As an estimate for the PO coordinates, one should select the lattice node reporting to the indicated MP, and as an estimate for t _{0 the} value calculated by the indicated MP. The simplest solution consists in sequentially polling the CPU of all MPs, however, much more efficient algorithms for parallel processing of information are currently known. For example, you can use the MP matrix, organized by the principle of the transputer. In this case, the MPs exchange data directly with each other, without using a common data bus, due to which the minimum element can be found in a small number of clock cycles.

 The above algorithm does not require complex calculations and can be performed in a short time. We simulated the indicated algorithm on an IBM PC / AT with a "PENTIUM" processor with a clock frequency of 120 MHz. For an optimally written assembler program, the calculation time for one point at N = 40 was 20 μs. In this case, the simplest ("bubble") algorithm for sorting and floating-point operations was used. The algorithm actually considered can easily be implemented without the use of floating-point operations, since the calculation of the square root can easily be reduced to tabular calculations. In general, estimates show that when using effective MPs, taking into account the computational costs associated with allocating samples with the same IR, identifying the subscriber, testing and self-organizing the system, the time for solving each problem in determining the coordinates will be no more than 50 μs. Accordingly, to solve in full all of the tasks set forth in clause 1, no more than 10 CBs are needed.

 In some cases (for example, if the territory with a small number of subscribers falls into the coverage area of a given CA), it may be appropriate to use universal computing tools. In this case it is advisable to use the iteration methods described in clauses 3.2, 3.3.

After an estimate is established for t ₀ and software coordinates for each receiver (including those excluded in clause 5 of the algorithm), the residual value can be set. After sorting the samples according to the residuals in ascending order, we will establish K + l receivers in whose area of responsibility the software falls (see section 3.4). For each of these receiving devices, an estimate can easily be made for the error in determining the time δt _i :
δt _i = t _i -t ₀ -L _i . (1)
These errors are recorded in the appropriate database. After a sufficiently long operation, an error distribution histogram can be obtained for each receiver. If for some receiving device the mathematical expectation of an error is significantly different from zero, it should be assumed that the specified device is either malfunctioning, or its coordinates are determined with errors, or the delay of the propagation time of the synchronizing signal is determined with an error.

 The database also records the distances between the software and each receiving device in whose area of responsibility the software is located. These data allow a statistical assessment of the radius of the zone of responsibility of each receiving device.

 In addition to identifying faulty devices, an important task of the CA is to determine for each receiving device the optimal selection threshold or, what is also, the optimal message flow transmitted by each receiving device (see clause 3.4). Setting the optimal selection threshold allows you to increase the system availability factor and reduce computing costs.

 To solve this problem, it is necessary for each reference to establish whether this reference came from the zone of responsibility of the receiving device. If so, then the value of the relative amplitude of the signal is entered into the corresponding database, i.e. the serial number of the signal in the array of signals received, sorted by decreasing amplitude, received during the clock cycle of the receiving device. After a long operation of the system, a histogram of the relative amplitude of the signals coming from the zone of responsibility of the receiving device can be obtained, which will allow you to set the optimal selection threshold. Indeed, consider a specific example.

Let K = 10, K '= 12 (see Section 3.4) and some receiver will receive 300 messages • s ^-1 . From the table. 1 and 2 of clause 3.4 it follows that the system availability factor is 0.83. During the system’s operation, after collecting sufficient statistics, it was found that with a probability of 0.99 the relative amplitude of the signal received by this receiver from subscribers in its area of responsibility does not exceed 40. Let the CA reduce the “scheduled task” for receiving messages to 50 s ^-1 . From the table. 1 and 2 it is seen that, even for all K 'receivers, the probability of error-free reception of messages will be reduced by 0.01 due to the "underestimated""scheduledtask", due to a decrease in the likelihood of conflict when transmitting messages, this probability will increase and will be 0.981 • 0.99≈0.97, i.e. the system availability factor will increase to 0.995.

4 LIST OF FIGURES ILLUSTRATING THE INVENTION
FIG. 1 Schematic appearance of a city multifunctional radio communication system of a subscriber with a central station with identification of the subscriber and determination of his location. A functional diagram of the device is shown in FIG. 2.

 Each subscriber of the system 15.16 is equipped with a transmitter for transmitting radio messages to the CA 11, and each radio message contains a unique identification code of the subscriber. The CA establishes the final recipient of the message of the subscriber - user 12. Messages of subscribers are received by the network of receiving devices 1 - multi-position radar station (MPLS), and all (or almost all) buildings of the serviced territory are equipped with MPRL receivers. A method for receiving devices is also shown in FIG. 8 and 9. With this placement method, due to the multipath nature of the propagation of radio waves in a city, some of the receiving devices will receive a “direct” signal from the subscriber, and some will receive the signal from the subscriber after it is reflected from local objects.

 The method for determining coordinates developed by us (see Section 3.2) allows us to determine the coordinates of the subscriber with high accuracy under these conditions, even if cheap receiving devices with low accuracy in determining the time of arrival of the signal front are used.

 An important property of the proposed system is the ability to service a significant stream of subscribers' messages in the same frequency range without transmitting any information providing multichannel from the DS to the subscribers, which is possible due to the method we developed for organizing information exchange between subscribers and receivers (see Section 3.4 )

 Despite the significant flow of messages in general, the number of messages transmitted to the CA by each individual receiving device is not large, and a dedicated telephone line 8 is used to connect the receiving devices with the hub 9. The output of the hub is a fiber optic line 10. The receiving devices can have connectors 17 for connecting external devices 18.19, while ensuring effective two-way wired communication between external devices and the CA.

 To ensure the synchronization of the receiving devices, a geostationary artificial earth satellite 14 is equipped with a transmitter.

 To determine the coordinates of the receiving devices after the deployment of the system, a helicopter 13 is equipped with a transmitter.

 FIG. 2. Functional diagram of a city multifunctional radio communication system of a subscriber with a central station with identification of the subscriber and determining his location in the preferred embodiment.

 Each receiving device 1 is connected by a dedicated telephone line 8 to one of the hubs 9. The connection between each receiving device and the hub is bidirectional. In a preferred embodiment, the concentrator is installed in a substation of a public telephone network. For example, in the conditions of Moscow there are about 100,000 buildings and 400 substations of the city telephone network. If we assume that one hub is installed at each substation, then a total of 400 hubs are needed, each of which serves about 1000 receiving devices. A dedicated telephone line is also used to power the receiving devices and protect them from unauthorized access.

 In a preferred embodiment, each receiver has two radio frequency channels, one for receiving subscriber messages and one for receiving a sequence of timestamps providing system synchronization. A synchronization generator (GS) 14 is intended for transmitting synchronizing signals, which is preferably installed on a geostationary artificial earth satellite. Each receiving device includes means for measuring the amplitude of messages received from subscribers, and conducting amplitude selection. If the subscriber’s message passes the selection threshold, the receiving device determines the time of its arrival and transmits the subscriber’s message, time of its arrival, estimate of its amplitude in some arbitrary units to one or several central stations (CA) 11, into the coverage area of which it falls. Each receiving device in standalone mode maintains the selection threshold at such a level that the number of messages of subscribers passing the selection threshold per unit time is equal to the set established for each receiving device by CA commands (Section 3.4).

 A certain number of CAs are connected to each other by communication lines 10. Each hub is connected to at least one CA. The connection between the hub and the CA is bidirectional. The CA transmits commands to the receiving devices that establish the operating mode of the receiving devices and hubs. The CA commands to the hub establish the coverage area of each CA, i.e. correspondence between the numbers of the receiving devices and the numbers of the "interested" CA. Receivers can be transferred at the command of the CA to normal operation, the mode of determining the coordinates of the receiving devices after the deployment of the system, the mode of determining the coordinates of the jammer. In the normal mode of operation, the CA commands establish for each receiving device the optimal message flow of subscribers passing the selection threshold. Owing to the method of receiving devices placement and the method of amplitude selection that we have proposed, it is not necessary to transmit any information providing multichannel to subscribers, and all subscribers of the system can work on the same frequency channel and transmit messages at arbitrary points in time, i.e. the system is completely stochastic.

 The CA performs the identification of the subscriber, and if the subscriber is a moving object, determines its coordinates. The CA also establishes the final recipient of the message of the subscriber (user 12) and transmits at its disposal all the information received. Simultaneously with determining the coordinates, the CA performs testing of the receiving devices and sets for each receiving device the minimum flow of messages that pass the selection threshold at which the system availability factor is at a given level.

 The receiving devices of the system may have connectors 17 for connecting various external devices, for example, a traffic light 18, a device for servicing credit cards 19. In this case, two-way wired communication between the external device and the CA is provided.

 FIG. 3. Determination of coordinates by the hyperbolic method.

и в заранее неизвестный момент времени t₀ излучает фронт сферической радиоволны. Имеется 4 приемных устройства, координаты антенн которых

известны с высокой степенью точности. Каждое из этих устройств определяет время поступления фронта сферической радиоволны ПО на свою антенну в некоторой произвольной, но одинаковой для всех устройств временной шкале.The software is at a point with previously unknown coordinates

and at a previously unknown time t ₀ radiates the front of a spherical radio wave. There are 4 receivers whose antenna coordinates

known with a high degree of accuracy. Each of these devices determines the time of arrival of the front of a spherical radio wave of software on its antenna in some arbitrary, but the same time scale for all devices.

Фиг. 4, 5. Распространение радиоволн при наличии отражающих поверхностей. Для волн дециметрового диапазона бетонные перекрытия, кирпичная кладка, конструкции из дерева и стекла, грунт, пресная и морская вода могут рассматриваться как идеальные диэлектрики.L _i - the distance between the i-th receiving device and software,

FIG. 4, 5. Propagation of radio waves in the presence of reflective surfaces. For decimeter waves, concrete floors, masonry, wood and glass structures, soil, fresh and sea water can be considered ideal dielectrics.

When radio waves are reflected from local objects (walls of buildings, bridges, lawns, etc.), there is both diffuse scattered and directional reflection. Diffuse scattering can be neglected, because the roughness of the reflecting surfaces is small compared to the long wavelength. The characteristic value of the reflection coefficient under normal ray incidence in the city is in the range of 0.6-0.9. Directional reflection occurs in the direction prescribed by geometric optics. If we assume that the reflecting surfaces are flat, then in the presence of a signal source f, a complete picture of the electromagnetic field can be obtained by taking into account imaginary images of the source f ', f'',f''', f ⁽⁴⁾ , as well as numerous images of imaginary sources (for simplicity not shown in the figure). All source images work in sync with f. The signal from each imaginary image propagates in a solid angle stretched over a reflective surface. The figure shows the solid angle within which the source signal f '' propagates (Fig. 4 is a top view, Fig. 5 is a side view in the direction of arrow A).

 FIG. 6. Explanation of a method that, according to the author of WO 93/04453, calculates the arrival time of the front of a software pulse located outside the line of sight from the antenna of the receiving device 1 at point 2, which would have occurred if building 20 were not available.

 Let the software move from point 1 to point 2. In this case, the pulse duration will increase due to the appearance of a direct beam. We replaced the “curve” signal with a “direct” one. If we apply the method proposed in the patent to this situation, we will conclude that the “curve” signal is replaced by an even more “curve".

 FIG. 7. The spreadsheet presents the results of solving the problems of determining coordinates by the hyperbolic method (Section 2.3).

 FIG. 8, 9. The method of placement of the receiving antennas MPRLS.

 The condition of good visibility of the territory from the side of the MPRLS antennas is completely equivalent to the condition of good visibility of the antennas of the MPRLS from any point in the territory.

 The MPRLS antennas, as it were, indicate the dimensions of the building.

 In a preferred embodiment, the antenna is attached directly to the housing of the receiving device. The housing of the receiving device has a bracket for attaching to the roof of the building. The antenna overhang beyond the horizontal dimensions of the building is (0.5-1) m. The figure shows a horizontally located antenna for receiving a sequence of synchronizing pulses from a geostationary artificial earth satellite and a vertically located antenna for receiving subscribers' messages.

 FIG. 10. A schematic plan of a section of the territory of Moscow adjacent to ul. Usievich on the site from d. 10a to d. 2.

 FIG. 11. The figure shows a plot of urban territory (top view). Corner points of buildings are equipped with MPRLS receiving devices; for clarity, the figure shows only 7 such devices.

 The figure shows a picture of the propagation of wave fronts, which would have occurred if the receiving devices of the MPRLS were replaced by transmitters, and the subscriber had at his disposal a receiver rather than a transmitter. Due to the reversibility of the ray path, the problem under consideration is completely equivalent to the original one.

 The figure is the result of solving on a computer the task of determining the coordinates of the subscriber in the manner proposed in this patent. The coordinates were determined under the assumption that there are at least 5 direct subscriber signals received by the MPRLS, and the standard deviation of the error in determining the arrival time of the fronts of direct signals is 20 ns (6 m).

 The calculated subscriber location is indicated by a “+” sign. At this point, signal 5 has a negative residual, and the remaining signals have a positive residual.

 FIG. 12. For any point in the hatched region, the residuals for all signals are positive. It is assumed that the corner points of the buildings are equipped with receiving devices. For simplicity, only wavefronts corresponding to direct rays are shown.

 FIG. 13. The coordinates of the receiving devices (see Fig. 10) and an example of the source data for the calculation.

 FIG. 14-27. The results of mathematical modeling of coordinates determination problems (to clause 3.3).

 FIG. 28.29. The increase in the duration of the pulse during its propagation in urban conditions due to multipath propagation.

 FIG. 30-33. Signal distortion due to the multipath nature of propagation in a city and a method for estimating signal amplitude.

 The figure shows the envelopes of the radio pulses: FIG. 30 - source and FIG. 31 - 33 - received by receiving devices located at various points in the city. Signals are assumed to be received by devices having a wide bandwidth. In addition, it is assumed that the subscriber’s transmitter has a high growth rate of the output signal amplitude (see FIG. 39).

The figure also shows some selection threshold U _- . If we use its maximum value U _MAX (pulse in) as an estimate of the pulse amplitude, then an inaccuracy in the amplitude estimate arises due to the presence of a multitude of signals having a random amplitude and phase at the input of the receiving device. It is reasonable to use the maximum value of the time derivative of the envelope as an estimate of the signal amplitude. In this case, the effects associated with multipath propagation are minimized.

 FIG. 34. The radiation pattern of a transmitting antenna mounted above the surface of an ideal dielectric.

 FIG. 35-38. Selection and estimation of signal amplitude.

 The figure shows the input circuits of the receiver.

If the voltage U = U ₀ • sinωt is applied to the oscillation branch, then the voltage on the capacitor of the circuit increases according to the law U _C = U ₀ • Q • (1-exp (-ωt / 2Q)) • sin (ωt + α). The stationary value of the amplitude of the forced oscillations as t _ → ∞ is U ₀ • Q. It can be shown that when using a quadratic detector at the output of the differentiating circuit, we obtain a pulse whose maximum amplitude is proportional to U $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ , i.e. squared stationary value of the amplitude, which would have occurred in the absence of multipath distortion. Accordingly, it is reasonable to use the maximum value of its derivative as an estimate of the amplitude of the signal. The figure shows the voltage plots on the loop antenna (t.1, Fig. 36), on the capacitor (t. 2, Fig. 37) and at the output of the differentiating chain (t.3, Fig. 38). The diagrams are built under the assumption that the quality factor of the circuit is Q = 10 and that, due to spurious parameters, the high-frequency component at the output of the differentiating circuit is eliminated.

 FIG. 39. The shape of the pulse at the output of the transmitter if a broadband power amplifier is used as the output stage.

 FIG. 40. The shape of the pulse at the output of the transmitter, unacceptable for solving problems of determining coordinates with high accuracy.

 FIG. 41. A section of a highway with extremely high traffic intensity.

The movement is made in 6 rows in each direction. For each car there are 10 linear meters of a row (linear density of 1200 km ^-1 ). Each vehicle is equipped with an HC and transmits a message to the CA once every ten seconds.

 Receiving devices are located at intervals of 50 m on both sides of the highway.

 The figure shows the zone of responsibility of the receiving device 1 (double hatching) and the conflict zone (ordinary hatching). The responsibility zone contains ≈ 360 cars, the conflict zone is ≈ 1000. The amplitude of the message of the subscriber located on the border of the conflict zone (point 3) is at least three times lower than the amplitude of the message of the subscriber located on the border of the zone of responsibility (point 2). For this reason, if the selection threshold of the receiving device 1 is set so that the receiving device receives 100 messages every second, messages from all subscribers in the area of responsibility will certainly be included in the number of received messages.

 FIG. 42. A sequence of short rectangular pulses without high-frequency filling that can be used to transmit messages.

 FIG. 43. Message coding as a sequence of wave trains.

 FIG. 44. Functional diagram of the HC in the simplest version.

 FIG. 45. The functional diagram of the HC in the preferred embodiment.

 FIG. 46. The sequence of synchronizing pulses (time stamps).

 FIG. 47. Functional diagram of the receiving device MPRLS (station).

 FIG. 48. Synchronization of the clock generator (GTI).

 FIG. 49. The appearance of the receiving device MPRLS. Antenna 32 is designed to receive messages from subscribers, antenna 42 is designed to receive clock pulses.

 FIG. 50. Determination of the coordinates of receiving devices by radar methods when deploying the system.

 To determine the coordinates of the receiving device 1, the helicopter 13 sequentially "freezes" at several points, the coordinates of which are known with a high degree of accuracy. The helicopter is equipped with a clock receiver and a transmitter.

 FIG. 51. Functional diagram of the hub.

 FIG. 52. Using a dedicated telephone line to power the receiving devices and protecting the receiving devices from unauthorized access.

 FIG. 53. Functional diagram of a specialized computer (ST) of the central station.

Claims (4)

1. A method for determining the coordinates of a moving object (PO), including emitting a signal from a moving object and determining the arrival times of signals to a plurality of spatially separated receiving devices, transmitting the arrival times of signals to a computer center (VC) and determining the coordinates of the software, characterized in that the network is deployed receivers in an amount of N ≥ 3, and their location points are selected with the calculation of being in direct line of sight from each point of the served area of space at least K receiving troystv with performance conditions 3 ≤ K ≤ N, wherein K is selected based on the required accuracy to determine the coordinates of software, while the other receivers can receive the signal ON after its reflection from local objects, for each receiver estimate the range of-area reception device R _{i max} - maximum distance remote from said point device serviced by the receiving region of space, for which said receiver is one of the K nearest to said point of receiving devices locat yaschihsya line of sight from the specified point on VTS determined receiver m, transmits a CC least from time _{t i - t m = min (} t _1), and from further consideration exclude receptors for which t - t _min> R _max , where R _max = max (R _{i max} ), consider a discrete set of points inside a sphere of radius R _max centered at the location of the receiving device m, and if you know the condition that the software coordinates satisfy, then consider a discrete set of points inside specified sphere and satisfying the indicated condition, and the smallest distance between the points of the set is selected based on the required accuracy for determining the coordinates of the software, for each point of the specified set, the distance L _{i is} determined equal to

from the set point to each of the receiving devices, where (x _i , y _i , z _i ) are the coordinates of the i-th receiving device, and (x, y, z) are the coordinates of the set point, the values of t _i - L _{i are} sorted into the order of their increase, determine the receiving devices for which the values of t _i - L _i take the first K places in the sorted array of values of t _i - L _i , and the rest of the receiving devices are excluded from further consideration and calculate the value Λ (x, y, z), equal to Σ (t _i -L _i - (1 / K) Σ (t _i -L _i )) ² , where the summation is performed according to the numbers of receivers not excluded from the considered and to estimate the coordinates of the software, choose a point of a discrete set for which the quantity Λ (x, y, z) is minimal.  2. A method for identifying subscribers and determining their location, including the delivery of coded radio messages by subscribers, the reception of radio messages from subscribers with multiple spatially separated base stations, the transmission of subscribers' messages and the times they arrived at the central station (CS), characterized in that the radio frequency communication lines between the subscribers and base stations are one-way from the subscriber to the base station, and receiving devices are used as base stations, system subscribers are equipped with devices and call (HC) the CA, and the power of the HC transmitters is selected based on the requirements of the subscribers to the probability of error-free reception of the subscriber’s message, sufficient to determine the coordinates with a given degree of accuracy by the number of receiving devices (PU), and the transmitter power is higher for subscribers whose requirements for the specified probability higher, and the power of the subscriber transmitters that have the same requirements for the specified probability are the same, each receiving device performs an amplitude selection of subscriber messages and amplitude measurements messages that have passed the selection threshold, and the selection threshold is maintained at such a level that the number of messages passing the selection threshold during a given time interval is equal to the specified set by the CA commands for this receiver, sort messages from subscribers who have passed the selection threshold during a specified time interval by the magnitude of the amplitude in descending order, and each message is assigned its number in the sorted array and transmitted to the CA along with the message and the time it arrived, to the CA For each control unit and each message transmitted by the control unit, it is established whether this message has arrived from the responsibility area of the given control unit, and among messages received from the responsibility area, a message with the maximum number is set, for each control unit, an empirical function is constructed for distributing the maximum message number received from the zone of responsibility of this PU, and the number of messages passing the selection threshold at a given time interval is determined at which the probability of error-free reception of the message the receiving device is not lower than the set one, and the message flow passing the selection threshold is minimal, and the indicated optimal value of the stream is transmitted to the control unit as a command to the receiving device.  3. The method according to claim 2, characterized in that the signal at the output of the video amplifier PU is differentiated, the messages are selected according to the derivative, the maximum value of the signal derivative is determined, and the obtained value is used as an estimate of the message amplitude.  4. A radio communication system for subscribers with a central station with identification of subscribers and determining their location, comprising subscribers equipped with coded radio transmitters, a plurality of spatially separated base stations, at least one central station (DS) and a plurality of communication lines between base stations and a DS, characterized in that the radio frequency communication line between subscribers and base stations is made one-way from the subscriber to the base stations and the base stations are receiving devices and, receiving devices are mounted on all buildings of the serviced territory at points indicating the upper dimensions of the buildings, it is equipped with hubs, each of which is connected to a group of receiving devices with dedicated telephone lines and microwave or optical communication lines with at least one DS, and the receiving device is powered over a dedicated telephone line, and the hub is a power source for receiving devices and with unauthorized access to a receiving device or a dedicated telephone On the given line, the concentrator generates an alarm signal, receiving devices include means for conducting amplitude selection of subscribers' messages, means for measuring the amplitude of messages that have passed the selection threshold, and means for automatically maintaining the selection threshold at such a level that the number of messages passing the selection threshold per unit time, equal to the set for the given receiving device by the CA commands, the receiving devices are equipped with connectors for connecting various external devices - traffic lights and and to serve the credit card units.

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