RU2555860C2 - Navigation system - Google Patents

Abstract

FIELD: physics, navigation.

SUBSTANCE: invention relates to radio navigation. The navigation system consists of multiple transmitters and may include a control subsystem. Access protection of a transmitter signal is achieved by: varying the transmitted pseudorandom sequence; varying the temporal arrangement of the pseudorandom sequence in a signal subframe; encrypting the navigation message; absence of data in the navigation signal and the need for authorisation. The navigation system implements autonomous or non-autonomous handover. During of non-autonomous handover, the navigation receiver interacts with the control subsystem through a communication system. The control subsystem transmits the necessary data to the navigation receiver, receives data therefrom and controls operation of transmitters.

EFFECT: protecting a navigation system from unauthorised access, enabling authorisation of navigation receivers therein and implementing handover therefor.

7 cl, 8 dwg

Description

The invention relates to radio navigation.

Currently, satellite navigation systems such as GPS, GLONASS, etc. are widely known [1]. Navigation receivers capable of navigating (positioning) using the radio signals of these systems are widespread. One of the disadvantages of satellite navigation systems is the low power of the radio signals from satellite transmitters. For this reason, the radio signals reaching the navigation receivers of satellite navigation systems are very weak. This makes it difficult or completely impossible to use satellite navigation systems for navigation in dense urban areas, indoors, and in other difficult cases where the radio signals of these systems undergo strong attenuation.

Navigation support systems such as A-GPS or their analogues can improve the performance of the navigation receiver of satellite navigation systems in difficult conditions [2]. Depending on the support option, the navigation receiver through the communication system can receive from the satellite ephemeris support system, approximate coordinates of its location, send to the computer center the characteristics of the received radio signals (for example, delay, frequency, etc.) to calculate its location and obtain the result, and also receive other supporting data. Typically, in such cases, the communication system is a cellular (mobile) communication system, and the navigation receiver is integrated into the cellular (mobile) telephone. Cellular (mobile) communication systems have their own capabilities to more or less accurately determine the location of a cellular (mobile) telephone and send it this result. Some of these features are described in [3]. The use of support systems allows you to speed up the start of the navigation receiver, improve the detection and capture of weak radio signals. Unfortunately, support systems alone cannot improve the quality of radio signals received by the navigation receiver and. as a result, there may be a relatively large navigation error in difficult conditions.

There are also ground-based radio navigation systems. In this case, the distances between the transmitters of the radio navigation system and the navigation receiver are much smaller than in the case of the use of satellite navigation systems, which provides a much higher level of radio signal power. Ground-based radio navigation systems can be used for navigation in dense urban areas, indoors and in other difficult cases. In addition to the high power of radio signals, the advantages of terrestrial radio navigation systems are the lack of inaccuracies in determining the coordinates of their transmitters, the absence of the influence of the ionosphere on radio signals, the lesser effect of the troposphere on radio signals, the flexibility and the possibility of optimizing the terrestrial transmitter network.

In particular, the Locata ground-based radio navigation system is known [4]. The Locata navigation system is a terrestrial network of transmitters. The transmitters are divided into subnets and broadcast navigation radio signals, which in general are very similar to the radio signals of satellite navigation systems. A navigation receiver adapted to receive and process signals from Locata transmitters, being in the coverage area of any of its subnets, is capable of independently navigating, generally very similar to navigation (positioning) via radio signals from satellite navigation systems.

The main differences between the Locata system and satellite navigation systems are: the temporary separation of channels (WRC) in the subnet (the temporary separation of the radio signals of the transmitters in the subnet); the change in the process of operation of the temporary location of the transmitter signal within the subframe; different navigation message information at each transmitter; arbitrary permissible operating frequencies of subnets; A different synchronization system for subnet transmitters and subnet groups [4-7].

The Locata navigation system is selected as the prototype and has the following disadvantages: the ability of any (unauthorized, unauthorized) user who has the appropriate navigation receiver to use this system for navigation; lack of handover for the navigation receiver between different subnets; lack of interaction (in addition to transmitter signals) between the navigation system and navigation receivers, in particular, complicating the change of transmitter signals during its operation and changes in the structure and operation mode of the navigation system; the complex structure of broadcasting signals via WRC, requiring an appropriate navigation receiver. The described disadvantages in the corresponding respect give rise to the disadvantages of the navigation receiver of the Locata system signals and the methods of its operation.

The prior art described here is described in more detail in the literature [1-7], which is incorporated herein by reference. The technologies described in [5-7] are used to implement the Locata system.

The purpose of the invention is the creation of a navigation system with the absence of these disadvantages of the prototype.

SUMMARY OF THE INVENTION

In general, the navigation system consists of several transmitters transmitting radio navigation signals, with the help of which any navigation receiver capable of processing these signals is able to carry out navigation - determine its coordinates and, if possible, its other characteristics, for example, speed, motion vector and etc. The navigation system may include a control subsystem necessary to control the operation of the transmitters and / or to interact with navigation receivers. Radio navigation signals in this description may also be referred to as navigation signals or radio signals, or navigation radio signals, or signals. The radio navigation signal of any transmitter, in its essence, may contain a rangefinder code modulating the carrier frequency of this transmitter.

I. Navigation system structure and synchronization

Navigation system transmitters can be divided into groups that are subnets. The navigation system may consist of separate transmitters not included in structural units. A mixed version of the network structure is also possible, based on the two options listed above.

For the correct operation of the navigation system, an important role is played by the synchronization of the transmitter signals. General rule: the signals of those transmitters that are used by the navigation receiver (or other devices) to implement navigation must either be synchronized, or relative time offsets can be determined for them in any way possible. This general rule can be implemented in various specific ways, in particular, using the same synchronization as used in the prototype system [4-7].

1. The first synchronization option involves the direct synchronization of transmitter signals. In this case, the signals of these transmitters are radiated into the air synchronously.

2. The second option involves the transmission of information on the synchronization parameters between certain transmitters as part of the information (navigation messages) of their navigation signals. In this case, the signals of these transmitters can be emitted to the radio asynchronously, but according to the amendments extracted from the navigation messages of the transmitters, this non-synchronism can be taken into account.

3. The third option involves the transmission of information on the synchronization parameters between certain transmitters as part of the information received by the navigation receiver through interaction with the control subsystem.

4. The fourth option involves determining the synchronization parameters between certain transmitters through the control subsystem (or through other devices). In this case, the control subsystem (or other devices) also performs the function (process, calculation) of navigation, and the navigation receiver receives only the result of navigation.

5. The fifth option involves any possible combination of all the above synchronization options.

Thus, all or part of the transmitter signals of one subnet or several subnets can be synchronized. Alternatively, transmitter signals within the same subnet may not be synchronized. A navigation receiver or other devices can use the signals of transmitters of one subnet or several subnets for navigation, or the signals of individual transmitters (not included in any structural units), or an arbitrary combination of all these cases.

II. Channel separation

1. The first option involves the use of frequency division multiplexing (PDK) for transmitters. An analogue is the GLONASS system [1]. In this case, each transmitter at a given carrier frequency transmits a radio navigation signal corresponding to it. The arrangement of carrier frequencies along the spectrum can be arbitrary. However, given the large dynamic range of the radio signals. It is advisable to perform PDA without superimposing the spectra of signals of different frequency channels. PDA is possible with any implementation of the navigation system under section I. For example, PDA is within the same subnet, while other subnets can use the same frequencies. Or, for example, PDA between the signals of several subnets. The main (but not obligatory) option for the transmitter during PDA is the constant transmission of a given rangefinder code.

2. The second option involves the use of WRC. An analog is the Locata system [4]. In contrast to the Locata system, it is also possible to introduce protective time intervals between signals of different channels. VRK is possible with any implementation of the navigation system in Section I. For example, VRK is within the same subnet, while other subnets can use the same time intervals. Or, for example, WRC between the signals of several subnets. The main (but not obligatory) option for the transmitter at the RCS is the transmission of a given rangefinder code in the allotted time intervals. The protective time intervals eliminate the disadvantage of the Locata system - the superposition of signals of different channels in time due to different distances from different transmitters to the navigation receiver.

3. The third option involves the joint use of the Cheka and the Cheka and the Cheka (Cheka and the Cheka). In this case, the navigation system uses more than one carrier frequency, and for each of these carrier frequencies, channel separation is implemented in accordance with the previous embodiment. ChRK-VRK is possible with any implementation of the navigation system under section I.

It is assumed that the main option for any transmitter is to transmit a signal of only one channel. However, it is possible that one transmitter can transmit signals of several channels. Only one of its characteristics (for example, coordinates, time, etc.) corresponds to one transmitter at any given time.

III. Modulation

In general, the modulation of the carrier frequency of the transmitter of the navigation system can be any. Modulations of different transmitters may vary.

The preferred option is to modulate the carrier frequency with the rangefinder code of the pseudo-random sequence (PSP), and on top of this modulation (if necessary) is superimposed modulation of the information signal of the navigation message. Thus, the transmitter signal may be a spread spectrum signal in a direct sequence. A navigation message can be transmitted by adding the PSP signal and the information signal modulo 2.

The carrier frequency can be modulated using binary phase shift keying (BPSK), quadrature phase shift keying (QPSK) or other types of modulation. The manipulation speed for various components of the modulated transmitter signal may be arbitrary. For example, the in-phase QPSK component is modulated by the memory bandwidth with a speed of 1023 bits in 1 ms, and the quadrature QPSK component is modulated by the memory bandwidth with a speed of 10,230 bits in 1 ms. The various components of the modulated signal can be modulated in the same or different ways, these methods can be synchronous or non-synchronous, these components can transmit the same or different navigation messages or not transmit any messages.

Since the spectra of some modulated signals are symmetrical with respect to the carrier frequency (for example, BPSK, QPSK, amplitude keying, etc.), only one sideband of the modulated signal can be transmitted to the radio. Thus, one-way modulation can be used.

Thus, the signals of the transmitters of the navigation system can be modulated in a variety of ways and these methods are possible so far as they do not contradict other characteristics of the navigation system.

In particular, the transmitter signals can be modulated by methods known from other navigation systems [1, 2, 4].

IV. Navigation message

1. The first option assumes the absence of a navigation message in the transmitter signal. In this case, the navigation receiver receives the data it needs from other sources, for example, from the control subsystem and / or sends the parameters of the received signals to another device to perform the navigation function in it, and the navigation receiver receives only the navigation result.

2. The second option assumes the presence of a navigation message in the transmitter signal. In this case, the navigation message of any transmitter, by analogy with existing satellite navigation systems, can be structured into lines, subframes, frames, superframes, etc. The transmitter navigation message may contain all or some of the following data:

- error-correcting message coding information (check bits);

- reference points in the navigation message (for example, timestamps);

- transmitter coordinates and / or transmitter coordinate system;

- transmitter time;

- transmitter identifier (ID) (for example, transmitter number);

- ID of the structural unit of the system (for example, the subnet number or the number of the subnet control subsystem, etc.);

- ID of the structural unit of the navigation message (for example, line number);

- ID of the variant of the transmitted message;

- provisional amendments, synchronization amendments, etc .;

- ID of the rangefinder code (for example, the number of transmitted SRP);

- time of action (time to complete the action) of this message;

- ID of changing message parameters;

- data from other transmitters of the navigation system;

- data from other structural units of the navigation system;

- rough data (almanac) of a given transmitter;

- network coordinates (for example, the boundaries of the transmitter subnet);

- radius (or area) of the action of the given transmitter;

- ID of the adjacent transmitter (for example, the number of the adjacent transmitter);

- a message for a given navigation receiver;

- frequency plan (for example, carrier frequencies of subnet transmitters);

- message encryption information.

All message data or only a part of it can be encrypted. The rest may be presented in a public manner. Noise-resistant coding can be performed on already encrypted data.

The navigation message, if necessary, may contain other data than the above. The navigation message may contain data similar to those used in the prototype [4] or in other navigation systems [1-2]. It depends on the specific implementation of the navigation system in practice.

V. Access Protection

Below are some options for protecting the navigation system from unauthorized access (use).

1. The first option is to change in time the transmitted ranging code. In particular, there is a change in the transmitted bandwidth, that is, the transmitter of the navigation system at different points in time can use different bandwidths. In this case, only the navigation receiver that has information about which SRP is transmitted by the transmitter is able to use the signal of this transmitter for navigation.

Under different PSP can be understood PSP having the same duration, the same number of characters (bits), but with different code sequences. Fig. 1 shows an example of a navigation signal with different SRPs of the same duration T1 (t is time). Fig. 2 shows an example of a navigation signal with different SRPs of the same duration T2 and guard intervals of the same duration T3 (t is time). Variants of the navigation signal of one of the transmitters of the navigation system shown in Fig. 1 and 2 are not the only possible ones and are given as examples.

2. The second option is to change the temporary location of the rangefinder transmitter code within the subframe. In particular, the temporary position of the transmitter bandwidth within the subframe changes. Only the navigation receiver that knows the rule of alternating the transmitter bandwidth within the subframe is able to use the signal from this transmitter for navigation. This option is designed for VRK or for each individual carrier frequency with the ChRK-VRK. It is desirable that transmitters having common broadcast areas have a single mechanism for changing the temporal location of their rangefinder codes to prevent mutual overlapping of signals over time. Unlike the Locata prototype system, the rule for interchanging the transmit baseband transmitters in a subframe is not generally known.

3. The third option is to encrypt all or part of the transmitter’s navigation message. In this case, only the navigation receiver that knows the key (password) and the decryption algorithm of the navigation message of the transmitter is able to use the data from the message of this transmitter for navigation.

4. The fourth option is the absence of such a navigation message in the transmitter signal that would allow the navigation receiver to autonomously perform navigation. However, other characteristics of the transmitter signal may be well known. In this case, the navigation receiver may request the data it needs from the control subsystem in order to navigate. The navigation receiver can also send measurement data of the navigation signals of the transmitters to the control subsystem and get back the navigation result. Thus, only the navigation receiver that has access to the control subsystem can realize its navigation.

Any possible combination of the above four access protection options can also be implemented. If there is no need to protect the navigation system from unauthorized use, then you can not use these options. In this case, the navigation system, by analogy with the prototype system, can be an open (public) navigation system.

VI. Management subsystem, navigation receiver authorization

The navigation system may include a control subsystem for performing various functions for controlling the operation of transmitters and / or for interacting with navigation receivers. To interact with navigation receivers, the control subsystem can use a communication system. Such a communication system may be, for example, a cellular (mobile) communication system.

In turn, navigation receivers may include communication modules for communication with a control subsystem through a given communication system. To obtain the necessary data for its work, the navigation receiver through the communication system accesses the control subsystem. In case of successful authorization of the navigation receiver in the control subsystem, established interaction is performed with it. Otherwise, the interaction is not carried out.

Different methods can be used to authorize the navigation receiver in the control subsystem. In particular, the most obvious is the method of authorization through a cellular (mobile) communication system. In this case, the communication module of the navigation receiver calls the control subsystem through the communication system. The control subsystem checks the number of the communication module of the navigation receiver calling it and makes a decision on authorization or refusal of authorization. The numbers of the communication modules of those navigation receivers that are authorized for authorization are stored in the control subsystem. The numbers of the communication modules in this case are similar to the numbers of cell (mobile) phones or their analogues.

In particular, it is also possible to access the navigation receiver through the communication module and then through the Internet to a server belonging to the control subsystem. In this case, authorization in the server is performed according to the rules of interaction established between the server and the navigation receiver. This option is similar to accessing the navigation receiver via the Internet to an A-GPS support system [1-2].

To decrypt the encrypted navigation message of the transmitter, the navigation receiver must know the key (password) and know the decryption algorithm of this navigation message. Keys (passwords), decryption algorithms, and other relevant data can be issued to the navigation receiver by the owner of the navigation system and / or transmitted through interaction with the control subsystem and / or sent via the navigation message of the transmitter.

In general, any specific authorization mechanism for the navigation receiver in the control subsystem and / or in the navigation system as a whole is not mandatory. The authorization mechanism eliminates the possibility of unauthorized use of the navigation system. In the case of an open (public) navigation system, authorization can also be performed, but in this case, any navigation receiver can authorize in the control subsystem or interact with it without authorization.

VII. Operation of the navigation receiver in the navigation system

1. The first option is the autonomous operation of the navigation receiver in the navigation system. In this case, he does not need a control subsystem. The navigation receiver starts its work on its own, performs a search and detection of transmitter signals, performs navigation, and completes its work.

2. The second option is the interaction of the navigation receiver with the control subsystem. In this case, the navigation receiver can receive parameters (data) of the transmitter signals for their detection, processing and for navigation, send the necessary data to the control subsystem, receive the necessary data from the control subsystem. In this case, navigation can be carried out in the navigation receiver, or the result of navigation can be transmitted to the navigation receiver from the control subsystem.

When moving the navigation receiver in space, it can leave the broadcast zone (action) of some transmitters of the navigation system and enter the broadcast zone (action) of other transmitters of the navigation system. In this case, it is necessary to switch the operation of the navigation receiver from the signals of some transmitters to the signals of other transmitters, that is, handover is necessary. Also, the navigation receiver can generally enter the broadcast area (action) of the navigation system or start work in the broadcast area (action) of the navigation system. Also, the navigation receiver may generally leave the coverage area of the navigation system or shut down in the coverage area of the navigation system.

Two generalized handover options are possible.

1. Autonomous handover. At the same time, the navigation receiver is able to independently switch its work. This is possible if the receiver has the necessary information about the parameters of the signals of those transmitters in the coverage area of which it is located.

2. Non-autonomous handover. Such a handover is necessary in cases where the navigation receiver is not able to independently switch its work. This is possible if the receiver does not have the necessary information about the parameters of the signals of those transmitters in whose range it enters. This option of handover consists in interaction with a control subsystem. At the beginning of its operation, the navigation receiver requests through the communication subsystem the control parameters of the signals of the transmitters in whose range it is located. In this case, the location of the navigation receiver can be determined. Moreover, the navigation receiver, if necessary, can also extract data from the navigation messages of the transmitters. The control subsystem decides which signal parameters of which transmitters to transmit to the navigation receiver. Having received the necessary data from the control subsystem through the communication system, the navigation receiver starts to work according to the specified algorithm. If the navigation receiver moves in space, it may fall into the coverage area of other transmitters. At the same time, he can request the parameters of their signals from the control subsystem or the control subsystem can make a decision and send these parameters and / or other data. Moreover, the navigation receiver, if necessary, can also extract data from the navigation messages of the transmitters. This option of handover can also be applied in case of repeated operation of the navigation receiver with previously obtained data, for example, when restarting or re-entering the coverage area of the navigation system.

In the case of autonomous handover, the navigation receiver extracts the data it needs from the messages of the transmitters and / or from other sources (for example, from the Internet or from the memory of the navigation receiver). Transmitter navigation messages may contain signal parameters of other transmitters (including neighboring ones) and other data that allow for autonomous handover. Other sources may contain signal parameters of other transmitters (including neighboring ones) and other data allowing autonomous handover. Autonomous handover is also possible in case of insufficient data in the navigation receiver when it independently searches for new navigation signals.

In the case of a non-autonomous handover, the determination of the transmitters required by the navigation receiver for its operation may occur in the following circumstances.

1. The navigation receiver can independently determine the transmitters it needs to operate. These transmitters can be defined:

- from messages from other transmitters and / or according to the parameters of their signals;

- from messages from the same transmitters and / or according to the parameters of their signals;

- by the location of the navigation receiver and / or the knowledge of the location of the transmitters.

The transmitters required by the navigation receiver for its operation can also be determined by any possible combination of the above conditions and / or other conditions.

2. The navigation receiver can determine its coordinates in ways that are not related to the capabilities of its navigation. Then the transmitters can be determined by the location of the navigation receiver and the knowledge of the location of the transmitters. In another case, the navigation receiver transmits its coordinates to the control subsystem, and it determines which transmitters it needs to operate.

3. The control subsystem can set the coordinates of the navigation receiver that sent it a request for the transmission of data necessary for its operation.

The navigation receiver can determine its location in ways not related to its navigation capabilities, and the control subsystem can receive this location of the navigation receiver from itself or in another way. One of the options for determining such a location is the ability of cellular (mobile) communication networks to determine the location of cellular (mobile) phones [3]. In this case, a cell (mobile) phone must be understood as the corresponding communication module of the navigation receiver. The location can be used in the navigation receiver or sent by it to the control subsystem, or the control subsystem can receive it from the communication system.

The navigation receiver can roughly (approximately) determine its location offline by analogy with the almanac in satellite navigation systems [1-3], if this almanac is transmitted in the message of the transmitters and the corresponding processing of the signals of these transmitters is possible.

The navigation receiver, as a transmitter ID, can send any data to the control subsystem that allows it to uniquely determine the transmitter using a predetermined interaction algorithm.

The navigation receiver can identify the transmitter by its message. For example, in the message of the transmitter, the number of the transmitter or any other data is transmitted that allows the navigation receiver and / or control subsystem to uniquely identify this transmitter.

The navigation receiver, if possible, can identify the transmitter by its signal. For example, according to the memory bandwidth used in the transmitter signal or the used carrier frequency of the transmitter, and so on.

If the navigation receiver can identify the transmitters in the range of which it falls by the signals received from them, then it can request the control subsystem the signal parameters of these transmitters. This is possible when transmitting data on neighboring transmitters in the transmitter’s navigation message or if the navigation receiver can determine its neighbors by the signal of one transmitter. In this case, the receiver can decide which transmitters it needs to operate, and request the appropriate data from the control subsystem.

If the navigation receiver knows the coverage areas of the transmitters, it can, when determining its location, request from the control subsystem the signal parameters of those transmitters in whose coverage area it enters. If the navigation receiver knows the operating areas of the transmitters whose signals it is currently working with, it can, determining its location and deciding to leave their operating areas, request the control subsystem the signal parameters of other transmitters, in particular, request neighboring transmitters . The coverage areas of the transmitters can be stored in the memory of the navigation receiver, they can be transmitted in advance from the control subsystem or received in the navigation receiver in another way (for example, via Internet connection).

In the general case, the adjacent transmitter with respect to a given transmitter may be any other transmitter of the navigation system. However, it is desirable that for a given transmitter, its adjacent transmitters would be the closest transmitters surrounding it in space. It is also desirable that the predetermined transmitter and the adjacent transmitter have broadcast-overlapping broadcast zones to create a continuous signal coverage area of the navigation system.

The range of the transmitter can be defined as a certain range of the transmitter in a given coordinate system. The coverage area of the transmitter can be determined by some coordinates or some area in a given space. The coverage area of the transmitter can be determined in other ways.

Thus, if the navigation receiver knows its current coordinates and the fact that it is in the coverage area of a certain transmitter, then it can request the data of this transmitter from the control subsystem.

In the case of autonomous handover, if the navigation receiver knows its current coordinates and the fact that it is in the coverage area of a certain transmitter, then it may try to use the signal of this transmitter for navigation.

The navigation receiver may request data from other (for example, neighboring) transmitters if the number of signals used by it for navigation from different transmitters is reduced to a predetermined number.

The navigation receiver may request data from other (eg, neighboring) transmitters if it is located at a distance greater than that specified from this transmitter.

The navigation receiver can request data from other (for example, neighboring) transmitters if the number of transmitters whose signals it uses and is more than a specified distance from it becomes less than a specified number.

The navigation receiver may request data from other transmitters from the control subsystem in any other cases, if this is determined by the interaction algorithm between the navigation receiver and the control subsystem.

If the navigation receiver requests the control subsystem the necessary data and the control subsystem knows that it is out of range (all or less than a certain number) of the navigation system transmitters (outside the network), then the control subsystem may not satisfy the request of the navigation receiver. In response, the control subsystem can transmit information to the navigation receiver that it is offline. If the navigation receiver is aware that it is offline, then it may not request a control subsystem. In this case, it can also transmit information about its absence in the network to the control subsystem.

If the navigation receiver requests the control subsystem the necessary data and the control subsystem knows that he is leaving the transmitters of the navigation system (leaving the network), then the control subsystem may not satisfy the request of the navigation receiver. In response, the control subsystem can transmit information to the navigation receiver that it is leaving the network. If the navigation receiver knows that it is leaving the network, then it may not request a control subsystem. In this case, it can also transmit information about the process of leaving the network to the control subsystem.

The process of exiting the network can be considered the absence of transmitters, the data of which can be transmitted by the control subsystem to the navigation receiver or whose data can be requested by the navigation receiver, but have not yet been transmitted.

For autonomous and non-autonomous handover, the process of exiting the network can be considered the absence of transmitters, the data of which can be received by the navigation receiver, but have not yet been received by it.

In case of disruption of its operation, the navigation receiver may repeatedly request data from the control subsystem or not request it and use the old data if they are not outdated. The navigation receiver can promptly request transmitter data if they have changed or will be changed.

In the case of receiving data from the control subsystem and the inability to use them to navigate, the navigation receiver can report this control subsystem. At the same time, the navigation receiver can re-request the data it needs according to the established query algorithm. The control subsystem in the case of impossibility of navigation of the navigation receiver can send him data again and / or send new data. The re-request mode of the navigation receiver data can be determined by the control subsystem and / or it is contained in the navigation message (determined from the navigation messages of the transmitters) and / or can be determined in advance.

Data obsolescence is determined by data on the time of the data (or the end time) and their reconciliation with the time available to the navigation receiver.

The control subsystem may transmit to the navigation receiver and / or it may request all or some of the characteristics of any given transmitters listed in section IV.

Unused data for operation in the navigation system, the navigation receiver may store for reuse or may delete. Unused data can be deleted only after its obsolescence (inability to reuse). Unused data can be deleted by the navigation receiver independently or by command from the control subsystem.

In the particular case, the stand-alone handover or stand-alone operation mode can be defined differently: this is the case when the navigation receiver receives data from the control subsystem without a request and / or when its request must always be satisfied by the control subsystem.

The control subsystem can send the following data or their equivalents (respectively to Section V) to the navigation receiver:

- characteristics used in the signals of the transmitters;

- information or algorithms for changing the SRP transmitters used in the signals (for example, algorithms for self-determination in the navigation receiver the SRP transmitters used at a given point in time);

- characteristics of the temporary location in the subframes used in the signals of the transmitters of the SRP;

- information or algorithms for changing the temporal location in the subframes of the used IF signals in the signals of the transmitters (for example, an algorithm for independently determining in the navigation receiver the time when the transmitter began to transmit the received frequencies within the subframe);

- keys (passwords) for decryption of navigation messages of transmitters;

- decryption algorithms for navigation messages of transmitters and / or information about the characteristics of ciphers of navigation messages of transmitters.

In general, algorithms must be built into the navigation receiver, allowing it to work successfully in the navigation system in an autonomous mode (without a control subsystem) and / or in an offline mode (with a control subsystem).

Viii. Transmitter Interaction

In one embodiment of the navigation system, the control subsystem can control the operation of the transmitters. Here we consider only such control over the operation of transmitters that is relevant to the operation of navigation receivers. The control subsystem may transmit control commands to some or all of the transmitters of the navigation system individually. For this, the control subsystem can be connected to each individual transmitter by a communication system. Control commands from the control subsystem to the transmitter can change its signal.

For the navigation receiver to respond appropriately to a change in the received transmitter signal, the control subsystem can send a message to the navigation receiver in a timely manner. This message should be enough for the navigation receiver to continue to work with the transmitter signal after changing it. Also, the control subsystem can change the navigation message of the transmitter in order to notify the navigation receivers about changes in the signal of one or more transmitters. A command from the control subsystem may inform the navigation receiver of the need to receive an updated transmitter navigation message. The notification through the navigation message can also be a command to the navigation receiver about the need to request the control subsystem new data and / or receive new data from it.

Partition Summary

Sections I-VIII collectively provide many combinations for implementing a navigation system. The most important are sections V and VII, as well as the mechanisms of interaction of any navigation receiver with the navigation system, in particular, with the control subsystem. When the characteristics of some sections are implemented in the navigation system, all other characteristics of the navigation system may differ from those described in other sections. Thus, the joint execution of precisely such characteristics as indicated in sections I-VIII is optional and is understood in this form in the claims.

The navigation system (Fig. 3) consists of several transmitters with numbers from 1.1 to 1.N (remote control 1.1 ... remote control 1.N), which emit signals for use in navigation receivers. The emitted signals are shown in Fig. 3 and in other figures conditionally as broken broken arrows. The navigation receiver 2 (NP 2) uses these signals to carry out its navigation. The number of navigation receivers operating in the navigation system is theoretically unlimited.

Control subsystem 3 (PU 3) can interact with transmitters (Figure 4) and / or with navigation receivers (Fig. 5 and 6). This interaction is shown (or can be assumed) in the figures as arrows going from the control unit 3 to other devices or to the control unit 3 from other devices.

In the case of interaction with the control subsystem, the navigation receiver consists of a communication module 4 (MS 4) and a navigation module 5 (NM 5). The navigation module receives and processes navigation signals. The navigation module through the communication module can interact with the control subsystem of the navigation system (Fig. 7). This interaction is shown in Fig. 7 as arrows going from MS 4 to NM 5, and vice versa.

The transmitter (remote control 1) in the case of using the control subsystem also contains a communication module 6 (MS 6) and a transmitting module (PM 7) for the case of interaction with it (Fig. 8). This interaction is shown in Fig. 8 as arrows going from MS 6 to PM 7, and vice versa.

At the beginning of its operation, the navigation receiver communicates through the communication module with the control subsystem and requests the data necessary for its operation. The control subsystem identifies the navigation receiver, checks the request of the navigation receiver and, in the case of a positive decision, transmits the requested and / or other data to the receiver. The navigation receiver uses the obtained data to process the navigation signals of the transmitters, if necessary, extracts information from the signals of the transmitters and navigates. During operation, the navigation receiver's requests may be repeated in accordance with the handover procedure, in case of signal loss, and in other established cases. When you turn on the navigation receiver again, it can use the old data if it is not outdated and stored in it, or request data again from the control subsystem. The control subsystem, if necessary, also controls the operation of the transmitters, changing their operating modes, and, if necessary, notifies navigation receivers accordingly. The control subsystem can transmit data to the transmitter to change its signal according to the established interaction algorithm. The control subsystem can itself initiate communication with navigation receivers to transmit them the necessary data for operation. The interaction between the navigation receiver and the control subsystem is carried out according to the interaction algorithm established for them. If there is no need to communicate with the control subsystem or it is absent, the navigation receiver can work autonomously. Moreover, the data and algorithms necessary for him to work in the navigation system can be embedded in it, and / or extracted from the signals of the transmitters, and / or obtained from other sources.

Navigation in the navigation receiver can be performed similarly to the prototype or prior art [1, 2, 4]. For this, tracking of the delay and frequency of the transmitters of the navigation system can be used. By determining pseudorange and pseudo-velocities, having the coordinates of the transmitters and time parameters, the navigation receiver can determine its location in a given coordinate system, and, if possible, other navigation parameters.

Thus, in the claimed navigation system there are access protection mechanisms, authorization and handover. There is also the possibility of using PDA, facilitating the architecture of individual channels of the navigation receiver. Moreover, each channel can be optimized for the signal of a given transmitter. The above description of the invention allows to establish the achievement of the objectives of the invention.

Literature

1. Understanding GPS: principles and applications / editors], Elliott Kaplan, Christopher Hegarty. - 2nd ed, 2006.

2. Frank van Diggelen. A-GPS: Assisted GPS, GNSS, and SBAS. Artech House, 2009.

3. Gromakov Yu.A., Severin A.V., Shevtsov V.A. Location Technologies in GSM and UMTS: Textbook. allowance. - M.: Eco-Trends, 2005 .-- 144 p.: Ill.

4. ICD-LOC-100A. LocataNet Positioning Control Document 2011. Locata Corp Pty Ltd, September 2011. www.locatacorp.com.

5. US patent US 7616682 B2.

6. US patent US 7848397 B2.

7. US patent US 7859462 B2.

Claims (7)

1. A navigation system consisting of several transmitters, in particular with the possibility of dividing into subnets, in which case the number of subnets is at least equal to one, and the transmitters transmit radio navigation signals by which any navigation receiver capable of processing these signals is capable of navigation, and the navigation system contains a control subsystem, and the navigation receiver can receive relevant data about the signals of the transmitters necessary for it to navigation, from the control subsystem, and, in particular, the control subsystem contains a communication system for interacting with navigation receivers, moreover, the navigation system implements the handover of the navigation receiver, for which the transmitters necessary for the navigation receiver for its operation are determined, and the necessary data of these are transmitted to the navigation receiver transmitters, characterized in that the transmitters are defined in one or more of the following ways:
- the navigation receiver determines the transmitters necessary for its operation from the messages of other transmitters and / or by the parameters of their signals and requests from the navigation system the necessary data of the transmitters it defines;
- the navigation receiver determines the transmitters necessary for its operation from the messages of the same transmitters and / or by the parameters of their signals and requests from the navigation system the necessary data of the transmitters it defines;
- the navigation receiver determines the transmitters necessary for its operation by its location and / or knowledge of the location of the transmitters and requests from the navigation system the necessary data of the transmitters it defines;
- the control subsystem determines the location of the navigation receiver or receives it from it, and on the basis of this determines the transmitters necessary for its operation. 2. The navigation system according to claim 1, characterized in that the navigation receiver determines its location in ways that are not related to its navigation capabilities. 3. The navigation system according to claim 1, characterized in that the navigation receiver roughly determines its location using the almanac of the navigation system. 4. The navigation system according to claim 1, characterized in that the navigation receiver determines the transmitter from its navigation message, and / or its SRP, and / or its carrier frequency. 5. The navigation system according to claim 1, characterized in that the navigation receiver determines the transmitter from the navigation message, and / or from the SRP, and / or from the carrier frequency of another transmitter or several transmitters. 6. The navigation system according to claim 1, characterized in that the navigation receiver determines the transmitter if it is in its coverage area. 7. The navigation system according to claim 1, characterized in that the navigation receiver can request data from other transmitters if the number of signals used by it for navigation from the transmitters is reduced to a predetermined number, or the navigation receiver can request data from other transmitters if it is at a distance greater than than specified from a specific transmitter, or the navigation receiver may request data from other transmitters if the number of transmitters whose signals it uses and remote from it the distance is greater than the specified, becomes less than the specified number.

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