RU2018858C1 - Method of determining location of movable object - Google Patents

Abstract

FIELD: measurement technology; radio engineering. SUBSTANCE: movable objects radiate signal, which is subsequently re-radiated by reference stations. In this case a set of signals is formed, which permits to determine location of any movable object in any geographic point within the boundaries of active zone of the system. EFFECT: improved precision. 4 dwg

Description

 The invention relates to radio engineering and can be used in navigation, monitoring and control systems for the movement of air, water and land transport.

 Azimuthal-rangefinding radio systems containing a beacon and on-board equipment located on moving objects are known and widely used. At the same time, the domestic azimuth-rangefinding short-range navigation system of the RSBN allows you to determine the location of a moving object not only on it, but also on the ground beacon. Here, to determine the coordinates of objects on the beacon, the last signal is “Indication Request”, and the signals “Indication Response” are generated and emitted at the instants of coincidence of the received signal “Indication Request” with the azimuth signal. The signals "Response indication" received at the beacon correspond to the azimuth and range of each object relative to the beacon. This system does not provide a determination of the location of other objects on the objects themselves (see Modern short-range navigation systems for aircraft. / Ed. By G.A. Pakholkov. M: Transport, 1986, pp. 46-74).

 However, these systems have insufficient location accuracy.

 Known pulsed radio-technical systems for determining the location, allowing with high accuracy to determine the location of moving objects using the differential-ranging method (see, for example, G.P. Astafyev, V.S. Shabshaevich, Yu. A. Yurkov. Radio navigation devices and systems. M. : Owls, radio, p.656, or A.A.Sosnovsky and I.A. Khaimovich. Aviation radio navigation. M.: Transport, 1980, p.40, 61), consisting of a chain of fixed reference stations emitting sequentially one after another pulse signals with a period specified by the leading reference station to it, and stations (receiver indicators) installed on moving objects, at which signals emitted by reference stations are received, measuring time intervals between them and calculating the coordinates of this moving object.

 However, systems implementing this method do not provide positioning of moving objects at reference stations and other objects at a given moving object. The different operating principles of the differential-rangefinder and azimuthal-rangefinder (goniometric-rangefinder) systems do not allow to realize in the second system a technical solution to the problem of determining the location of moving objects at reference stations used in the first system.

 The aim of the invention is to increase the information content by determining the location of a moving object with its identification at reference stations and determining the location of this moving object at other moving objects or command and control centers.

 For this, in a differential-ranging system using sequential one after another radiation of several reference stations of pulse signals with a period specified by the leading reference station, receiving these signals on moving objects, measuring the time intervals between received signals and calculating the values of these intervals of coordinates of this moving object , after receiving signals of reference stations on each mobile object from each mobile object, they emit a pulsed radio signal with an individual for each of a different object with a delay relative to the signal of the leading reference station, receive these signals at reference stations and re-emit, receive re-emitted signals at other reference stations, select at the reference stations the signals of this moving object received directly and relayed by other reference stations, measure the differences in the arrival times of these signals and determine the location of this moving object by the differential-ranging method.

 To identify the signals received by the moving object with the corresponding reference stations, the signals emitted by the reference stations are encoded with an individual code for each reference station ("coding" is understood hereinafter in a broad sense: the color of the signal, which makes it possible to distinguish it from the others. This may be a difference in the carrier frequency , the repetition period, the duration of the pulses, the time interval between them, etc.), similarly, at the reference stations, the relayed signals of moving objects are encoded individually for this of the reference station with a code different from the indicated one, divide the pulse repetition period of the leading reference station by at least n + 1 intervals, where n is the number of moving objects (several time intervals can be assigned to one object), select the individual signal radiation delay on the moving object in accordance with the beginning of one of the n time intervals fixed for a given moving object, starting from the second, signals are selected at the reference station in time within the time interval corresponding to th moving object, and the duration of the time interval is selected in accordance with the maximum possible delay in receiving the relay signal relative to the radiation moment.

 In order to additionally determine the location of this moving object at other moving objects or command and control centers located at any point in the working area of the system, signals from this mobile object re-emitted by reference stations are received at other moving objects or command and control centers, they are temporarily selected within the time interval corresponding to this moving object, measure the differences in the times of their arrival and determine the coordinates of this moving volume at other moving objects or command and control points according to the measured differences and the own coordinates of another moving object or command and control point using the difference-ranging method, while the duration of the time interval is selected in accordance with the maximum possible delay time of the signal received at the moving object relayed by the reference stations regarding the moment of its radiation.

 The essence of the invention is determined by the fact that due to the individual delay and emission of signals by each moving object, reception and re-emission of these signals by reference stations, individual information appears on the time of reception of signals from any of the moving objects at each of the reference stations, which makes it possible to determine the location of all objects at any reference station or mobile facility.

 The given set of features is absent in the studied patent and scientific and technical literature on this issue, therefore, the proposed technical solution meets the criterion of "novelty."

 No devices or systems are known in which the coordinates of all moving objects could be determined on any of these objects without directly exchanging information about the coordinates between them, which allows us to state that the proposed method and the system that implements it meet the criterion of "materiality" of difference .

 In FIG. 1 and 2 shows a structural diagram of a system for implementing the proposed method.

 The equipment of the reference station (see Fig. 1) consists of a series-connected receiver 1, a first decoder 5, a chroniser 9, a first encoder 7, an OR element 6 and a transmitter 2. The equipment also includes a third decoder 3 connected to the output of the receiver 1, connected the second encoder 8, the output of which is connected to the second input of the OR element 6, the second decoder 4, the time selector 10, the delay unit 11 and the meter 12, the input of the second decoder is connected to the output of the receiver, the output of the second decoder to the first input m temporary selector 10, a second input temporary selector connected to the output of the delay unit 11, a temporary selector output - to the input of the meter 12 and the delay unit input - to the output of the first decoder.

 A feature of the leading reference station is the lack of communication between the output of the first decoder 5 and the input of the chronizer 9.

 The equipment of moving objects (see Fig. 2) includes a series-connected receiver 13, a first decoder 16, a first delay unit 17, an encoder 21, a transmitter 14, as well as a second decoder 15, a time selector 18, and a meter connected in series and connected to the output of the receiver 13 20. Between the output of the first decoder 16 and the second input of the temporary selector 18, a second delay unit 19 is included.

 The system operates as follows.

 The transmitter 2 of the leading reference station emits pulsed signals with a period specified by the chronizer 9, and encoded by the code assigned to this station (we will call this code synchronizing) by the encoder 7 via the OR element 6. The signal of the leading reference station is received by the receivers 1 of the slave reference stations, decoded by decoders 5 and through chronizers 9, encoders 7 and elements OR 6 launches transmitters 2 of the slave reference stations. The emitted signal is encoded by the synchronization code assigned to this slave station. The receiver 13 of the moving object receives the signals of the reference stations. The received signals are decoded by the decoder 16 and fed to the delay unit 17, where they are delayed relative to the signal of the leading reference station for the time assigned to this moving object and which is its distinctive feature.

 At the output of block 17, a signal is generated that is delayed relative to the signal of the leading reference station by a fixed time assigned to this moving object and which is its distinctive feature. This signal is encoded by the encoder 21 (common to all moving objects code) and is emitted by the transmitter 14.

 The signals of movable objects received by the receivers 1 of the reference stations are decoded by decoders 3 using encoders 8 are encoded by the information code assigned only to this reference station (different from the synchronization code assigned to this station) and transmitters 2 emitting the signals of movable objects are launched through the OR element 6.

 Information (re-emitted) signals of the reference stations are received by the receivers 1 of the reference stations and the receivers 13 of the moving objects, are decoded respectively by the decoders 4 installed on the reference stations, and the decoders 15 on the moving objects. Pulse signals obtained as a result of decoding, which carry information about the moments of arrival of signals from each reference station, through a time selector 10 for the reference station or a temporary selector 18 for a moving object, allowing one to select from its totality signals belonging to that moving object, the location of which is to be determined, enter the input of the meter 12 for the reference station or meter 20 for the moving object, which determines the location of the differential-ranging method in the same way as makes a meter in a known system. The delay block 11 (or block 19 for the equipment of a moving object), triggered by the clock signals from the output of the decoder 5 (16), allows the time selector to select the required time interval, i.e. select the necessary moving object.

 The receiving and measuring part of the equipment at the reference stations and at moving objects is absolutely similar in composition, communications, purpose and operation. This part of the equipment can be performed separately in the form of a special control and measuring point, which can be installed at any geographical point in the system coverage area.

 The time diversity of the signals carrying information about the location of each moving object, provides the opportunity not only to observe, but also to identify each of these objects.

+ τ_c - время, необходимое для излучения всеми опорными станциями синхронизирующих сигналов;
с - скорость распространения радиосигналов;
Д_м -расстояние между ведущей и самой удаленной от нее опорной станциями;
τ_c - длительность синхронизирующего сигнала отдельной опорной станции;
t=

+ T₁+τ_и - время, затрачиваемое на формирование и обработку сигналов одного подвижного объекта;
Т₁ - защитный временной интервал, учитывающий нестабильность схем формирования временных задержек и временных селекторов;
τ_и - длительность информационного сигнала опорной станции.Mathematically, the relationship between the repetition period of T signals emitted by the leading reference station, the maximum range of the system D, the number of moving objects working in it is described by the expression
T = t _c + Nt, (1) where t _c ≥

+ τ _c is the time required for all reference stations to emit synchronizing signals;
C is the propagation speed of radio signals;
D _{m - the} distance between the leading and the most remote from her reference stations;
τ _c - the duration of the clock signal of a separate reference station;
t =

+ T ₁ + τ _and is the time spent on the formation and processing of signals of one moving object;
T ₁ - protective time interval, taking into account the instability of the formation of time delays and time selectors;
τ _and - the duration of the information signal of the reference station.

 Useful location information is contained in time intervals between the information signals of reference stations received at the observation point (relayed signals of moving objects).

- время распространения радио- сигнала от подвижного объекта до опорной станции ОС1;
t_1н=

- время распространения сиг- нала от опорной станции ОС1 до пункта наблюдения ТН.Figure 3, where OS1, OS2, OS3 - installation points of reference stations with coordinates, respectively, X1, U1; X2, U2; X3, U3, PO - location of the moving object (coordinates XO, UO) and VT - location of the observation point (it can be a reference station, a moving object or any point in the coverage area of the system in which the corresponding equipment is installed) with coordinates X _n , Y _n , it is clear that if a radio signal is received at a time t _{about a} moving object, then at a point TN the signal relayed by the reference station OS1 will appear at a time
t ₁ = t ₀ + t ₀₁ + t _1н , where t ₀₁ =

- the propagation time of the radio signal from the moving object to the reference station OS1;
t _1n =

- signal propagation time from the reference station OS1 to the observation point of VT.

Accordingly, the relayed signal from the OS2 reference station will appear at the observation point of the VT at the moment
t ₂ = t _o + t _o2 + t _2n and
t ₃ = t _o = t _o + t _o3 + t _3н
Obviously, intervals can be fixed at the TN point
t ₁₂ = t ₁ - t ₂ = t ₀₁ + t _1н - t ₀₂ - t _2н (2)
t ₁₃ = t ₁ - t ₃ = t ₀₁ + t _1н - t ₀₃ - t _3н (3)
Note that in the expressions (2), (3) the value of t _{o is} absent. Thus, to determine the coordinates of a moving object, it is not necessary to know t _o - the exact moment of radiation of the signal by the moving object.

t

+

-

-
(4)

t

+

-

-
(5)
Графически решение сводится к отысканию точки пересечения двух представляющиx собой гиперболы линий положения.The coordinates of the moving object XO, UO can be calculated by solving a system of two equations with two unknowns

t

+

-

-
(4)

t

+

-

-
(5)
Graphically, the solution comes down to finding the intersection point of the two position line hyperbolas.

 Due to the fact that the information signals of the reference stations are encoded, there are no problems with distinguishing signals from them with the proposed method.

The coordinates of the moving object on this object itself can be determined from the same differences (2,3) and from the same mathematical expressions (4, 5) (in this case XO = X _n and YO = Y _n , i.e. the coordinates of the moving object coincide with the coordinates of the observation point). In addition, the radiation time of the signal t _o generated on it is known at each moving object, i.e. the signals of this object relayed by reference stations are simply response range-finding signals and the coordinates of a given moving object on it itself can be determined by a range-finding method in three ranges.

 The coordinates of this moving object can be determined on it by the most classical differential-ranging method by measuring the differences in the arrival time of synchronizing signals of three reference stations.

 Figure 4 shows the temporal structure of the signals.

 Signals are periodic. The period of their following is determined by the chronizer of the leading reference station. Part of the time interval in each period is reserved for the transmission of synchronizing signals by reference stations, and the rest of the time interval is divided into segments assigned to each of the moving objects. Within these time periods, the signal is emitted by a moving object and it is relayed to each of the reference stations. If this object does not work at the moment in the system, the time interval assigned to it remains free.

 In addition to special applications, the system according to the proposed method can be used to provide aerial processing of agricultural land, air sampling and radiation monitoring.

 When mobile stations equip special services, police, and public transport vehicles (the system can include up to 15-20 thousand mobile stations), such systems can become the basis for managing special transport and street traffic in large settlements, and much more efficient and cheaper than those designed in at present and until now practically unrealized because of their complexity, traffic control systems, since when equipping even a small part of urban transport (for example, public ennogo) on a computer dispatching traffic lights control center will provide a very rapid and complete picture of the distribution of the vehicles (in this case can easily be provided by special transport priority by assigning it specific numbers).

Claims (2)

 1. METHOD FOR DETERMINING THE LOCATION OF A MOBILE OBJECT (ON), including radiation from ground reference stations (OS) of at least three pulsed radio signals, characterized in that, in order to determine the location of the software at the observation point (PN) located at any geographical point located in the system coverage area, they emit a pulsed radio signal from each software, receive these signals on the OS and re-emit, encoding the re-emitted signals with an individual code for each OS, receive the re-emitted signals on the PN, measure differently The times of arrival of these signals determine the location of the software using the difference-ranging method.  2. The method according to claim 1, characterized in that, in order to increase the noise immunity during simultaneous operation and software by eliminating the interference of software signals, the OS emits synchronizing pulsed radio signals encoded by codes, individual for each OS, different from the codes of re-emitted signals, the pulse repetition period The OS is divided into at least n + 1 intervals, where n is the number of software, the pulsed radio signal from each software is emitted with an individual delay for this software relative to the synchronizing signal of the OS, the individual delay is the signal values for the software are selected in accordance with the beginning of one of the n time intervals fixed for the given software, starting from the second, the signals for the PN are selected in time within the time interval corresponding to the given software, the duration of the time interval is selected in accordance with the maximum possible delay of the relayed reception signal relative to the moment of radiation.

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