RU2845536C1 - Method of multi-position radar system information-telecommunication system functioning - Google Patents

Abstract

FIELD: radio engineering systems.

SUBSTANCE: invention relates to radio systems and can be used when building an information-telecommunication system for a multiposition radar system (MPRS) with cooperative processing and using an integrated approach to generating probing radar, communication and synchronizing signals. In the method of operating an information-telecommunication MPRS system, when selecting a signal-code structure of radio signals for MPRS operation, the type of a noise-like radio signal for MPRS operation is selected depending on the values of the effective bandwidth of the signal spectrum and effective signal measurement time. Selected noise-like radio signal is used as the radio signals emitted and received at the spaced apart positions of the MPRS. Selected noise-like radio signal is used to transmit information data.

EFFECT: high quality of operation of the information-telecommunication system of a multiposition radar system with easy implementation thereof.

1 cl, 1 dwg, 1 tbl

Description

The invention relates to the field of radio engineering systems and can be used, for example, in the construction of an information and telecommunications system of a multi-position radar system (MPRS) with cooperative processing and the use of an integrated approach to the formation of probing radar, communication and synchronizing signals.

Methods of multi-position radar are known [1, Chernyak V.S. Multi-position radar. - M.: Radio and communication, 1993.], [2, Averyanov V.Ya. Spaced radar systems. - Minsk: Science and technology, 1978], [3, Bakulev P.A. Radar systems. Textbook for universities. - M.: Radio engineering, 2004.]. In general, these methods of multi-position radar consist of the emission of radar signals, synchronized reception of reflected signals by equipment at spaced positions, combining and jointly processing signals and information to detect targets, measure their coordinates, determine trajectory parameters and subsequent identification.

These methods make it possible to realize the main advantages of multi-position systems compared to single-position systems - greater accuracy in measuring the location of targets in space and increased reliability in performing a tactical task, as well as the ability to form complex spatial viewing zones, better use of energy in a radar system, and increased noise immunity in terms of location signals.

The disadvantages of these methods are the high technical complexity in terms of synchronizing the equipment of mobile, spaced positions, as well as low survivability and reliability, determined by the data transmission channels of the spaced positions.

A method of multi-position radar is known [4, Russian Federation Patent No. 2332684, IPC: (2006.01) G01S 13/00. Method of multi-position radar, Kulikov A.L. Published - 27.08.2008]. The method consists of emitting radar signals, synchronized reception of reflected signals by equipment at distributed positions using power transmission lines, combining and jointly processing signals and information to detect targets, measure their coordinates, determine trajectory parameters and subsequent identification.

The implementation of the method allows to realize the main advantages of multi-position systems, in particular high accuracy.

The disadvantage of this method is the high technical complexity in terms of synchronization of the equipment of mobile spaced positions, dependence on additional external equipment - power lines, the impossibility of using mobile spaced positions, as well as low survivability and reliability, determined by the data transmission channels of the spaced positions.

A method for generating and processing signals in multi-range and multi-band radar systems is known [5, Russian Federation Patent No. 2684896, IPC: (2006.01) G01S 13/02. Method for generating and processing signals in multi-range and multi-band radar systems, Lyalin K.S., Meleshin Yu.M., Khasanov M.S., Oreshkin V.I., Federal State Autonomous Educational Institution of Higher Education "National Research University "Moscow Institute of Electronic Technology". Publ. - 16.04.2019]. The method consists in using signals with phase-code manipulation, ensuring the operation of the system in several working frequency bands and subsequent combining of the received signals into one wideband one.

The method allows to improve the resolution.

The disadvantages of the method are the limitations inherent in single-position systems, including low accuracy and reliability, relative to multi-position systems.

A method of multi-position radar for covert airspace control is known [6, Anoshkin I.M. Foreign multi-position radar systems for covert airspace control // Science and military security. - No. 1. - 2007.], [7, Karev V.V., Korol O.V., Kuznetsov A.A., Timakov D.A. Promising technology for determining the location of air objects in passive radar systems // Bulletin of SibSUTI. - No. 2. - 2015.]. The method consists in using signals from external radio emission sources (VHF radio broadcasting stations, television transmitters of analog or digital signals) as probing signals, while at spaced positions of the passive multi-position system, two-channel coherent reception of signals from the outputs of the antenna subsystem is carried out, providing the formation of two narrow beams in the direction of the air object and the external radio emission source, the beam in the direction of the air object scans the space in a given sector both in elevation and in azimuth. During the scanning process, signals and information are combined and jointly processed to detect air objects, measure their coordinates, determine trajectory parameters and subsequently identify them.

The method allows for covert radar detection of targets using information signals from external radio emission sources.

The disadvantages of this method are the high technical complexity in terms of synchronizing the equipment of mobile, spaced positions, dependence on additional external equipment - sources of radio signals for illumination, as well as low survivability and reliability, determined by the data transmission channels of spaced positions.

A method of functioning of the information and telecommunication system of a multi-position radar system is known [8, Svetlichny Yu.A., Degtyarev P.A. Synchronization and data transmission in radio engineering systems with geographically distributed segments // TUSUR Reports. - 2019. - Vol. 22. - No. 3 - Pp. 7-12], adopted as a prototype, which includes:

- selection of signal-code structures of radio signals for the operation of the MPRS;

- in the selection process, determining the choice of the structure of synchronizing, location and communication radio signals for the operation of the MPRS;

- during operation of the MPRS, emission and reception of radio signals at spaced positions of the MPRS, as radio signals emitted and received at spaced positions of the MPRS, the sequential use of synchronizing, location and communication radio signals;

- emission and reception of synchronizing radio signals at spaced positions of the MPRS;

- adjustment of clock generators at spaced positions based on the results of analysis of radiation and reception of synchronizing radio signals;

- emission and reception of location radio signals at spaced positions of the MPRS;

- processing of location information at distributed positions of the MPRS, formation of information data on their basis for transmission;

- transmission of information data by means of emission and reception of radio signals at spaced positions of the MPRS of communication radio signals, for transmission of information data the use of communication radio signals;

- implementation of cooperative processing of transmitted information data to obtain estimates of the location of detected objects.

The method ensures the formation of estimates of the location and other characteristics of detected objects with increased accuracy and reliability due to the possibility of using mobile, spaced positions, organizing independent channels for transmitting data from spaced positions, and cooperative processing of transmitted information data.

The disadvantage of the prototype method is its complexity, which consists of the need for sequential, periodically repeated formation of synchronizing, location and communication radio signals.

Thus, in the prototype, a periodic pulsed LFM signal with a constant phase is used as synchronizing radio signals, which is analyzed on the receiving side by the phase drift over time. The magnitude of the phase drift is taken as a measure of the coherence of the clock generators of the spaced positions.

After the application of synchronizing radio signals in the prototype, wideband signals of various types are used as location radio signals.

After using the location radio signals in the prototype, signals with M-QAM modulation with the corresponding time utilization factor are used as communication radio signals.

All three types of radio signals used in the prototype require certain hardware resources, which leads to a complex technical implementation of the method.

The objective of the invention is to simplify technical implementation while maintaining high accuracy and reliability.

To solve the stated problem, a method for the functioning of the information and telecommunications system of the multi-position radar system is proposed, for the implementation of which signal-code structures of radio signals are selected for the functioning of the MPRS, during the operation of the MPRS, radio signals are emitted and received at spaced positions of the MPRS, clock generators are adjusted at spaced positions based on the results of the analysis of the radiation and reception of radio signals, location information is processed at spaced positions of the MPRS, information data is formed on their basis for transmission, information data is transmitted by means of radiation and reception of radio signals at spaced positions of the MPRS of communication radio signals, and cooperative processing of the transmitted information data is carried out to obtain estimates of the location of detected objects.

According to the invention, in the process of selecting the signal-code structure of radio signals for the operation of the MPRS, a type of noise-like radio signal is selected for the operation of the MPRS depending on the values of the width of the effective band of the signal spectrum and the effective time of signal measurement, the selected noise-like radio signal is used as the radio signals emitted and received at spaced positions of the MPRS, and the selected noise-like radio signal is used for the transmission of information data.

The technical result is high quality of operation of the information and telecommunications system of the multi-position radar system with simplicity of its implementation.

The technical result is achieved by introducing new operations: in the process of selecting the signal-code structure of radio signals for the operation of the MPRS, selecting the type of noise-like radio signal for the operation of the MPRS depending on the values of the width of the effective band of the signal spectrum and the effective time of signal measurement, using the selected noise-like radio signal as radio signals emitted and received at spaced positions of the MPRS, using the selected noise-like radio signal for transmitting information data.

The drawing shows a structural diagram of a device that implements the proposed method of functioning of the information and telecommunications system of a multi-position radar system.

The combination of distinctive features and properties of the proposed method are not known from the literature, therefore it meets the criteria of novelty and inventive step.

The method of functioning of the information and telecommunications system of the multi-position radar system is implemented as follows:

1. Select signal-code structures of radio signals for the operation of the MPRS;

2. During the selection process, the type of noise-like radio signal for the operation of the MPRS is selected depending on the values of the width of the effective signal spectrum band and the effective signal measurement time;

3. During operation, the MPRS emits and receives radio signals at spaced MPRS positions;

4. The selected noise-like radio signal is used as the radio signals emitted and received at the spaced positions of the MPRS;

5. Adjust the clock generators at spaced positions based on the results of the analysis of radiation and reception of radio signals;

6. Process location information at distributed positions of the MPRS, and form information data on their basis for transmission;

7. Transmit information data by means of emission and reception of radio signals at spaced positions of the MPRS of communication radio signals; for transmitting information data, a selected noise-like radio signal is used;

8. Carry out cooperative processing of transmitted information data to obtain estimates of the location of detected objects.

To implement point 2, in the selection process, the type of noise-like radio signal for the operation of the MPRS is selected depending on the values of the width of the effective spectrum band of the signal and the effective time of signal measurement, i.e., the universal structure of the radio signal is determined. This means a structure capable of simultaneously providing a solution to the problems of synchronization, radiolocation and communication, solved by the MPRS during operation.

The basis for defining the universal structure of a radio signal is its ability to simultaneously meet the quality indicators of synchronization, radar and communication processes at the required level.

The quality indicators of the synchronization process of the equipment of distributed positions of the MPRS can include the standard deviation of the time scale estimate [9, Kryuchkov I.V., Filatov A.A. Synchronization of mobile modules of distributed radar systems // Bulletin of the Bauman Moscow State Technical University. Series "Instrument Engineering". - 2012. - No. 8 - P. 45-52]. On the other hand, it is known that the estimate of the potential accuracy of measuring the arrival time of a radio signal (standard deviation of the time estimate σ _τп ) is determined by the signal-to-noise energy ratio and the effective bandwidth of the signal spectrum _Δƒэ [10, Theoretical Foundations of Radar / Ed. V.E. Dulevich. - M.: Sov. Radio, 1964. - 732 p.]:

Thus, the parameter of the universal structure of the radio signal, which can affect the accuracy of synchronization, is the width of the effective band of the signal spectrum _Δƒэ . In this case, the greater the value of _Δƒэ , the smaller the standard deviation of the time estimate σ _τп and, consequently, the higher the accuracy of synchronization.

The quality indicators of the process of radar of the equipment of the separated positions of MPRS should include potential standard deviations of the estimates of the measured quantities. The first group of such quantities includes those for which indirect measurements are implemented, based on the estimate of time parameters, for example, in range-finding (multi-lateration) systems, the potential accuracy of measuring the delay time determines the potential accuracy of measuring the range, and in difference-range-finding systems, the potential accuracy of measuring the delay time between two received signals determines the potential accuracy of measuring the difference in ranges.

Since the assessment of the potential accuracy of the measurement of the arrival time of a radio signal is determined and _Δƒэ , then the potential accuracy of range measurement (RMS of range estimate σ _Rп ) is determined by (1) and

where c is the speed of light.

The potential accuracy of measuring the difference in ranges (RMS of the range estimate σ _ΔRп ) is determined by an expression of type (1) and

Where - the variances of the measurement errors of the arrival times of the first and second signals are determined by an expression of type (1).

Thus, the parameter of the universal structure of the radio signal, which can influence the accuracy of measuring the ranges and their differences, is the width of the effective band of the signal spectrum _Δƒэ . In this case, the greater the value of _Δƒэ , the higher the accuracy of the measurement.

The second group includes measured quantities for which indirect measurements are implemented based on the assessment of frequency parameters, for example, in Doppler systems the potential accuracy of measuring the signal frequency determines the potential accuracy of measuring the radial velocity [11, Theoretical Foundations of Radar / Ed. Ya.D. Shirman. - M.: Soviet Radio, 1970. - P. 365-377.]

On the other hand, it is known that the assessment of the potential accuracy of frequency measurement (frequency shift) (RMS of the frequency estimate σ _ƒп ) is determined by the signal-to-noise energy ratio and the effective time of signal measurement T _e [10, p. 296, Theoretical foundations of radar / Ed. V.E. Dulevich. - M.: Sov. radio, 1964. - 732 p.]:

Thus, the parameter of the universal structure of the radio signal, which can influence the accuracy of the radial velocity measurement, is the effective time of signal measurement T _e . In this case, the greater the value of T _e , the higher the accuracy of the measurement.

From (1)-(4) it follows that when measuring distances and speeds together, it is necessary to use noise-like (broadband) signals, since only for them can the spectrum width and duration be changed independently [12, p. 14, Varakin L.E. Communication systems with noise-like signals. - M.: Radio and communication, 1985. - 384 p.].

The quality indicators of the communication process of the equipment of the distributed positions of the MPRS should include potential characteristics of noise immunity and throughput.

Noise immunity is the ability of a communication system to withstand the impact of powerful interference. It includes the secrecy of the communication system and its noise immunity [12, p. 6]. Both of these properties are ensured by the size of the signal base

where Δƒ is the bandwidth of the communication channel, T is the signal duration.

The largest value of the signal base is for wideband signals, for them B>>1.

In particular, the reception of a broadband signal by a matched filter or correlator is accompanied by a signal amplification (or interference suppression) of 2⋅B times [12, p. 6].

Potential throughput, in accordance with Shannon's formula [Shannon K. Works on information theory and cybernetics. - M., 1963], is determined taking into account the previously introduced designations of the maximum transmission speed

where Δƒ is the bandwidth of the communication channel.

Thus, from (1)-(6) it follows that in order to ensure that the required level of quality indicators for synchronization, radar and communication processes is met simultaneously, the universal structure of the radio signal must have as large a signal base as possible, i.e. the signal must belong to the broadband class.

The basis for defining the universal structure of a radio signal is its ability to simultaneously meet the quality indicators of synchronization, radar and communication processes at the required level

Signals with such a structure may include, for example, noise-like signals, in particular, signals with an extended spectrum, which are obtained by using modulation with a change in phase according to a pseudo-random law. Pseudorandom code sequences must have good correlation properties; such sequences include Barker codes, maximum-length sequences (m-sequences), Gold sequences, Walsh sequences, and others. Signals with a linear frequency change (LFM), which also belong to the class of noise-like signals, also have good correlation properties.

Thus, broadband signals with PSP and LFM have high noise immunity and good correlation properties.

To implement point 4, the universal structure of the radio signal selected in point 2 for the operation of the MPRS is used - one of the types of wideband signal. The order of application of such signals for the implementation of synchronization processes is described, for example, in [9], [10], and for the implementation of radar processes, for example, in [10], [11].

To implement point 7, the universal structure of the radio signal selected in point 2 is used for the operation of the MPRS - one of the types of wideband signal. The procedure for using such signals to implement communication processes is described, for example, in [12].

Thus, the proposed method has the following distinctive features in the sequence of its implementation from the prototype method, which are presented in Table 1.

From the presented comparison table of the sequences of implementation of the prototype method and the proposed method, it is evident that in the proposed method, relative to the prototype method, in addition to the process of selecting the signal-code structure of radio signals for the operation of the MPRS, the type of noise-like radio signal for the operation of the MPRS is selected depending on the values of the width of the effective band of the signal spectrum and the effective time of signal measurement, the selected noise-like radio signal is used as the radio signals emitted and received at spaced positions of the MPRS, the selected noise-like radio signal is used for the transmission of information data, which leads to a positive effect - simplification of technical implementation while maintaining high accuracy and reliability.

The structural diagram of the device implementing the proposed method is shown in the drawing. The device includes: N spaced positions, each n-th spaced position includes a control and signal processing device (CSP) n. 1, a decoder of noise-resistant codes (DNC) n. 2, a buffer device (BD) n. 3, a device for generating signal-code constructions with a universal structure (DCSUS) n. 4, a detection device (DD) n. 5, a digital-to-analog converter with a high-frequency path (DAC) n. 6, an analog-to-digital converter with a high-frequency path (ADC) n. 7, an antenna device (AD) n. 8.

The output of UUOS n. 1 is connected to the input of UFSKUS n. 4, the first output of which is connected to the input of DAC n. 6, and the second output to the first input of UO n. 5, the output of the DAC is connected to the input of AU n. 8, and its output is connected to the input of ADC n. 7, the output of ADC n. 7 is connected to the second input of UO n. 5, the first output of which is connected to the first input of UUOS n. 1, and the second output of UO n. 5 is connected to the inputs of DNK n. 2 and BU n. 3. The outputs of DPK n. 2 and BU n. 3 are connected to the second and third inputs of UUOS n. 1, respectively. Each n-th spaced position is connected through AU n. 8 and the free space with the remaining spaced positions through their AU 1.8, …, (n-1).8, (n+1).8, …N.8.

The UUOS n. 1 controls the formation in the UFSKUS n. 4 of a signal-code construction with a universal structure, capable of simultaneously providing the solution of synchronization, radar and communication problems solved by the MPRS during operation. In this case, in each UUOS 1.1 - N.1 of the spaced points 1 - N, there is a priori general information about the pre-selected signal-code construction with a universal structure and its parameters, which make it possible to isolate time sections of the emitted signals containing, for example, simultaneously synchronizing and location structures or simultaneously location and information-communication structures. From the first output of the UFSKUS n. 4, the formed quadrature digital samples of the signal-code constructions with a universal structure are fed to the input of the DAC n. 6, and from the second output of the UFSKUS n. 4, the quadrature digital samples of the signal-code constructions with a universal structure and their parameters are fed to the first input of the UO n. 5. The digital samples are converted by the DAC n. 6 into analog high-frequency signals, which from the output of DAC n. 6 are fed to the input of AU n. 8, where they are emitted into space taking into account the spatial position of the supposed target and the remaining spaced positions 1, …, n-1, n+1, …N. The location signals of the n-th spaced point reflected from the targets, as well as the location, synchronization and information-communication signals from the remaining spaced positions 1, …, n-1, n+1, …N taking into account their spatial position, are received by AU n. 8 and from its output are fed to the input of ADC n. 7. In ADC n. 7, the analog high-frequency signals are converted into quadrature digital readings and from the output of ADC n. 7 are fed to the second input of UO n. 5. In UO n. 5, based on the signals received from UFSKUS n. 4 signals and their parameters are used to detect location signals of the n-th spaced position reflected from targets taking into account their spatial position; information about these detections is received from the first output of the UO n. 5 to the first input of the UUOS n. 1 for partial or complete processing of location information. Based on the processed location information, the UUOS n. 1 generates information data for transmission to the remaining spaced positions 1, …, n-1, n+1, …N based on the control of the formation in the UFSKUS n. 4 of a signal-code structure with a universal structure.

In UO n. 5, detection of synchronizing signals of the remaining spaced positions 1, …, n-1, n+1, …N is also implemented; the results of their detection and evaluation of their parameters are received from the first output of UO n. 5 to the first input of UOS n. 1 for adjusting the clock generator at the n-th spaced position based on the results of the analysis of radiation and reception of synchronizing fragments of radio signals.

In addition, in the control unit n. 5 of the n-th spaced position, detection of location signals of the remaining spaced positions 1, …, n-1, n+1, …N, reflected from targets taking into account their spatial position, as well as information-communication signals of the remaining spaced positions 1, …, n-1, n+1, …N also taking into account their spatial position is implemented. The results of detection of these signals and the detected signals themselves from the second output of control unit n. 5 are fed to the inputs of DPC n. 2 and BU n. 3

In DPC n. 2, the time relationships (phases) of the received data signals are restored, the restored signals are sent from the output of DPC n. 2 to the second input of UUOS n. 1, while at the same time, the signals detected by UO n. 5, delayed for the time of noise-resistant decoding, are sent to the third input of UUOS n. 1 from the output of BU n. 3, thereby allowing radar tasks to be performed during the reception of information and communication signals of the remaining spaced positions 1, …, n-1, n+1, …N.

Taking into account the spatial position of the supposed target and the remaining spaced positions 1, …, n-1, n+1, …N is implemented through spatial selection in AU n. 8, for example, based on its construction as a digital antenna array.

High accuracy of determining the radar parameters of targets is ensured by the choice in paragraph 2 of the procedure for implementing the method of a universal radio signal structure that ensures high quality indicators of synchronization and radar processes, and in paragraph 4 of the use of such radio signals.

High reliability, as in the prototype, is ensured by the possibility of transmitting information data by means of emission and reception of communication radio signals at spaced positions of the MPRS. At the same time, high quality of communication during data transmission between positions is also ensured by the choice in paragraph 2 of the order of implementing the method of a universal structure of a radio signal with high communication quality indicators, and in paragraph 7, the use of these signals for transmitting information data.

The technical implementation of the method is simplified by the fact that in the process of selecting the signal-code structure of radio signals for the operation of the MPRS, a universal structure of the radio signal is determined for the operation of the MPRS, which is capable of simultaneously providing a solution to the problems of synchronization, radar and communication. In this regard, instead of forming, as in the prototype, three types of radio signals, which leads to a complex technical implementation of the method, only one type of radio signal is used - a type of noise-like radio signal is selected for the operation of the MPRS depending on the values of the width of the effective band of the signal spectrum and the effective time of signal measurement, which reduces the complexity of the technical implementation of the proposed method by 3 times.

Thus, the proposed method, as well as the prototype method, allows for high accuracy and reliability. In addition, the presented comparative assessment of the complexity of the technical implementation of the proposed method relative to the prototype method shows a reduction in the complexity of the technical implementation of the proposed method.

Claims (1)

A method for operating an information and telecommunications system of a multi-position radar system (MPRS), in which signal-code structures of radio signals are selected for the operation of the MPRS, during the operation of the MPRS, radio signals are emitted and received at spaced positions of the MPRS, clock generators are adjusted at spaced positions based on the results of an analysis of the emission and reception of radio signals, location information is processed at spaced positions of the MPRS, information data is formed on their basis for transmission, information data is transmitted by means of emission and reception of radio signals at spaced positions of the MPRS of communication radio signals, cooperative processing of the transmitted information data is carried out to obtain estimates of the location of detected objects, characterized in that in the process of selecting a signal-code structure of radio signals for the operation of the MPRS, a type of noise-like radio signal is selected for the operation of the MPRS depending on the values of the width of the effective bandwidth of the signal spectrum and the effective time of signal measurement, and the radio signals emitted and received at spaced positions of the MPRS are used selected noise-like radio signal, for transmission of information data use selected noise-like radio signal.