Distance measurement-based double-station radar clock synchronization method and system, and storage medium

Abstract

The invention belongs to the technical field of radars, and relates to a double-station radar clock synchronization method and system based on distance measurement and a storage medium. The method comprises the following steps: acquiring orbit information of a precise orbit satellite; the first radar station and the second radar station simultaneously emit linear frequency modulation ranging signals with positive frequency modulation slope and negative frequency modulation slope to the precise orbit satellite target at an agreed moment taking the clock of the first radar station as a reference; the first radar station and the second radar station measure a single-base one-way distance measurement result and a double-base distance measurement result according to the distance measurement echo signals; calculating an inter-station clock synchronization error according to a bistatic ranging result; according to the single-base one-way distance measurement result and the double-base distance measurement result, the inter-station hysteresis is judged; and correcting the clocks of the two stations according to the inter-station clock synchronization error and the inter-station hysteresis. According to the invention, high-precision clock synchronization is realized by using the rule that bistatic ranging errors are caused by clock synchronization errors between radar stations.

Description

Technical Field

[0001] This invention belongs to the field of radar technology, specifically relating to a ranging-based bistatic radar clock synchronization method, system, and storage medium. Background Technology

[0002] Inter-station clock synchronization accuracy is a key technical indicator for distributed radar technology. Multi-station imaging, multi-station positioning, and multi-station tracking technologies based on distributed radar all require high-precision clock synchronization between multiple stations. Therefore, modern radar technology places increasingly higher demands on the accuracy of inter-station clock synchronization. Existing bi-station clock synchronization methods include the clock-transfer method, the master station timing method, and the timing center method. However, these methods suffer from problems such as implementation complexity, unsuitability for long-baseline networking, and insufficient initiative.

[0003] High-precision clock synchronization is not only fundamental to achieving multi-station collaboration, but also crucial for improving the overall performance of radar networks. In the future, the accuracy of clock synchronization between radar stations will continue to improve, thereby driving the development and application of distributed collaborative technologies.

[0004] In scenarios with multiple radar stations widely distributed across a single area, existing dual-station clock synchronization methods include the transport clock method, the time synchronization center method, and the master station time synchronization method. The transport clock method involves transporting the clocks from one radar station to another after synchronization, which presents challenges such as cumbersome transportation and the need for continuous operation of the transport clock during transport. The time synchronization center method uses a clock source with high frequency stability to provide unified time synchronization to all radar stations, achieving high-precision clock synchronization, but it also suffers from insufficient initiative and requires the assistance of a time synchronization center. The master station time synchronization method utilizes the master station's clock to synchronize the clocks of other secondary stations, achieving inter-station clock synchronization without the need for a time synchronization center independent of the radar network, but it is unsuitable for long-baseline networks. Summary of the Invention

[0005] Therefore, in view of the problems existing in the existing bistatic clock synchronization methods, this invention proposes a ranging-based bistatic radar clock synchronization method, system and storage medium. Relying on broadband ranging technology with ranging accuracy up to the centimeter level, it only needs to measure the distance to a stationary target at a distance. By utilizing the law that the bistatic ranging error is caused by the clock synchronization error between radar stations, real-time and high-precision clock synchronization in long baseline radar networking scenarios can be achieved.

[0006] In a first aspect, embodiments of the present invention provide a ranging-based bistatic radar clock synchronization method, comprising the following steps:

[0007] S1. Obtain orbital information of the cooperating precision-orbiting satellites;

[0008] S2, the first radar station, and the second radar station simultaneously transmit linear frequency modulation ranging signals with positive and negative frequency modulation slopes to the precision orbit satellite target at an agreed time based on the clock of the first radar station.

[0009] S3. Based on the ranging echo signal, the first radar station and the second radar station measure the single-base single-way ranging results of the first radar station and the second radar station's self-transmission and self-reception, as well as the bi-base ranging results transmitted by the first radar station and received by the second radar station, and transmitted by the second radar station and received by the first radar station.

[0010] S4. Calculate the inter-station clock synchronization error based on the bi-base ranging results;

[0011] S5. Determine the inter-station lag based on the single-base single-journey ranging results and the double-base ranging results;

[0012] S6. Based on the inter-station clock synchronization error and inter-station lag, the clocks of the two stations are corrected to achieve high-precision clock synchronization.

[0013] Preferably, the formula for calculating the inter-station clock synchronization error Δt in step S4 is:

[0014]

[0015] Where c is the speed of light, R 12 R is the bistatic ranging result transmitted by the first radar station and received by the second radar station. 21 The second radar station transmits the bi-base ranging results to the first radar station, which then receives them.

[0016] Preferably, the formula for determining inter-station lag in step S5 is:

[0017]

[0018] Among them, R 11 R 22 These are the single-base, single-way ranging results from the first and second radar stations, respectively, obtained through self-transmission and self-reception. (R) 12 The bistatic ranging results transmitted from the first radar station and received by the second radar station; (·) o This represents the true value of the distance measurement result when there is no clock synchronization error.

[0019] When the bibase ranging result R 12 Greater than the true value of bibase measurement without clock synchronization error When the clock of the second radar station lags behind the clock of the first radar station, it is determined that the clock of the second radar station is behind the clock of the first radar station; when the bi-base ranging result R 12 Less than the true value of bibase measurement without clock synchronization error At that time, it was determined that the clock of the first radar station was lagging behind the clock of the second radar station.

[0020] Secondly, embodiments of the present invention provide a ranging-based bistatic radar clock synchronization system, comprising the following modules:

[0021] The orbit information acquisition module is used to acquire orbit information of cooperative precision orbit satellites;

[0022] The ranging signal transmission module is used to transmit linear frequency modulation ranging signals with positive and negative frequency modulation slopes to a precision orbit satellite target at an agreed time, with the clock of the first radar station as the reference, simultaneously through the first radar station and the second radar station.

[0023] The ranging module is used to measure the single-base, one-way ranging results of the first radar station and the second radar station based on the ranging echo signals from the first radar station and the second radar station, as well as the bi-base ranging results transmitted by the first radar station and received by the second radar station, and transmitted by the second radar station and received by the first radar station.

[0024] The synchronization error calculation module is used to calculate the inter-station clock synchronization error based on the bi-base ranging results;

[0025] The judgment module is used to determine the inter-station lag based on the single-base single-trip ranging results and the double-base ranging results.

[0026] The correction module is used to correct the clocks of two stations based on the clock synchronization error and the lag between stations, so as to achieve high-precision clock synchronization.

[0027] Thirdly, embodiments of the present invention provide a computer storage medium storing computer-executable instructions thereon, which, when executed by a computer, are used to implement the above-described dual-station radar clock synchronization method.

[0028] Compared with the prior art, the main technical effects achieved by the present invention include: the present invention only needs to measure the distance of a stationary target at a distance, and by taking advantage of the law that the clock synchronization error between radar stations causes bistatic ranging error, it can achieve real-time and high-precision clock synchronization in long baseline radar networking scenarios. Attached Figure Description

[0029] Figure 1 This is a schematic diagram illustrating an application scenario of the dual-station radar clock synchronization method in an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram illustrating the time delay analysis of the ranging signal transmitted by the second radar station lagging behind the first radar station in an embodiment of the present invention.

[0031] Figure 3 This is a schematic diagram illustrating the time delay analysis of the ranging signal transmitted by the first radar station lagging behind the second radar station in an embodiment of the present invention.

[0032] Figure 4This is a flowchart of a ranging-based bistatic radar clock synchronization method in an embodiment of the present invention. Detailed Implementation

[0033] This invention utilizes a precision-orbiting satellite as a cooperative target. After compensating for Doppler shift and range migration caused by the satellite's high-speed motion during signal processing, clock synchronization is achieved using high-precision ranging information. First, based on the acquired azimuth and elevation information of the precision-orbiting satellite target, two stations simultaneously transmit linear frequency-modulated ranging signals with positive and negative frequency-modulated slopes to the precision-orbiting satellite target at a predetermined time. Then, based on the ranging echoes, the two stations measure the monostatic and bistatic distances. Next, based on the monostatic and bistatic ranging results, the inter-station clock synchronization error and inter-station lag are estimated. Finally, based on the clock error estimation results, the clocks of the two stations are corrected to achieve high-precision clock synchronization between them.

[0034] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but the implementation of the present invention is not limited thereto.

[0035] Example

[0036] To simplify the model, this embodiment assumes that the satellite can be considered approximately stationary during the extremely short duration of a single ranging operation. In practical applications, the Doppler effect and range cell migration introduced by its high-speed motion can be pre-compensated using known satellite ephemeris data to ensure ranging accuracy.

[0037] like Figure 1 As shown, the first radar station 1 and the second radar station 2, which have long baselines and wide distribution, simultaneously transmit linear frequency modulation (LFM) ranging signals with positive and negative frequency modulation slopes to a precision orbit satellite target (hereinafter referred to as a precision orbit satellite target) so that they can be distinguished at the receiving end of each radar station.

[0038] Let R be the single-base, one-way ranging results of the first radar station 1 and the second radar station 2, which are transmitted and received independently. 11 R 22 The bistatic ranging result transmitted by radar station 1 and received by radar station 2 is R. 12 The bistatic ranging result transmitted by the second radar station 2 and received by the first radar station 1 is R. 21 Since single-base, single-journey ranging results are not affected by clock synchronization errors, in the absence of clock synchronization errors, we have:

[0039]

[0040] in,(·) o This represents the true value of the distance measurement result when there is no clock synchronization error.

[0041] In the presence of clock synchronization error, we have R 12 ≠R 21 In this scenario, the clock of the second radar station 2 lags behind the clock of the first radar station 1 by Δt (Δt > 0). Both stations simultaneously transmit ranging signals to the precision-orbiting satellite target at time t0, which is based on the clock of the first radar station 1. Figure 2 As shown. Where, τ 11 τ is the time delay from the transmission of the signal from radar station 1 to the precision orbit satellite target and back to radar station 1. 22 τ is the time delay from the transmission of the signal from Radar Station 2 to the precision orbit satellite target and back to Radar Station 2. 12 τ is the time delay from the first radar station 1 to the precision-orbiting satellite target and back to the second radar station 2; 21 This refers to the time delay from the second radar station 2 to the precision orbit satellite target and back to the first radar station 1.

[0042] according to Figure 2 ,have:

[0043]

[0044] Multiplying both sides of the above equation by the speed of light *c*, and converting the time delay measurement into a distance measurement, we have:

[0045]

[0046] Similarly, the time delay analysis of the clock of radar station 1 lagging behind the clock of radar station 2 by Δt (Δt>0) is as follows: Figure 3 As shown. According to Figure 3 ,have:

[0047]

[0048] Based on the above analysis, it can be concluded that the bistatic ranging result R... 12 R 21 The clock synchronization error Δt between the two stations is estimated as follows:

[0049]

[0050] In addition, the results of bistatic ranging R can be compared. 12 Compared with the single-base single-pass ranging result R 11 R 22 To determine the inter-station lag, i.e.:

[0051]

[0052] In the above judgment formula, when the bibase ranging result R 12 Greater than the true value of bibase measurement without clock synchronization error When the clock of the second radar station lags behind the clock of the first radar station, it is determined that the clock of the second radar station is behind the clock of the first radar station; when the bi-base ranging result R 12 Less than the true value of bibase measurement without clock synchronization error At that time, it was determined that the clock of the first radar station was lagging behind the clock of the second radar station.

[0053] Finally, based on the estimated inter-station clock synchronization error Δt and the inter-station lag, the clocks of the two stations are corrected to achieve high-precision clock synchronization between the two stations.

[0054] Based on the above analysis, such as Figure 4 As shown, the ranging-based bistatic radar clock synchronization method in this embodiment includes the following steps:

[0055] S1. Obtain the orbital information of the precision orbit satellite; wherein, the orbital information includes the azimuth and elevation information of the precision orbit satellite relative to the first radar station and the second radar station, respectively.

[0056] S2, the first radar station, and the second radar station simultaneously transmit linear frequency modulation ranging signals with positive and negative frequency modulation slopes, respectively, to the precision orbit satellite target at an agreed time t0, with the clock of the first radar station as the reference.

[0057] S3, the first radar station, and the second radar station measured the single-base, single-pass ranging result R based on the ranging echo signal. 11 R 22 And the bistatic ranging result R 12 R 21 Among them, the single-base single-journey ranging results are not affected by the inter-station clock synchronization error, while the dual-base ranging results are affected by the inter-station clock synchronization error.

[0058] S4. Calculate the inter-station clock synchronization error Δt based on the bi-base ranging results: Where c is the speed of light.

[0059] S5. Determine the inter-station lag based on the single-base single-trip ranging results and the double-base ranging results. The specific determination formula is as follows:

[0060]

[0061] In the above judgment formula, when the bibase ranging result R 12 Greater than the true value of bibase measurement without clock synchronization error When the clock of the second radar station lags behind the clock of the first radar station, it is determined that the clock of the second radar station is behind the clock of the first radar station; when the bi-base ranging result R 12 Less than the true value of bibase measurement without clock synchronization error At that time, it was determined that the clock of the first radar station was lagging behind the clock of the second radar station.

[0062] S6. Based on the inter-station clock synchronization error and inter-station lag, the clocks of the two stations are corrected to achieve high-precision clock synchronization.

[0063] Based on the same inventive concept, this embodiment also provides a ranging-based bistatic radar clock synchronization system, including the following modules:

[0064] The orbit information acquisition module is used to acquire orbit information of satellites in precise orbits.

[0065] The ranging signal transmission module is used to transmit linear frequency modulation ranging signals with positive and negative frequency modulation slopes to a precision orbit satellite target at an agreed time, with the clock of the first radar station as the reference, simultaneously through the first radar station and the second radar station.

[0066] The ranging module is used to measure the single-base, one-way ranging results of the first radar station and the second radar station based on the ranging echo signals from the first radar station and the second radar station, as well as the bi-base ranging results transmitted by the first radar station and received by the second radar station, and transmitted by the second radar station and received by the first radar station.

[0067] The synchronization error calculation module is used to calculate the inter-station clock synchronization error based on the bi-base ranging results;

[0068] The judgment module is used to determine the inter-station lag based on the single-base single-trip ranging results and the double-base ranging results.

[0069] The correction module is used to correct the clocks of two stations based on the clock synchronization error and the lag between stations, so as to achieve high-precision clock synchronization.

[0070] The implementation process of each of the above modules corresponds to steps S1-S6 of the bistatic radar clock synchronization method, and the detailed implementation process will not be elaborated here.

[0071] In addition, this embodiment also provides a computer storage medium storing computer-executable instructions, which, when executed by a computer, are used to implement the steps of the above-described bistatic radar clock synchronization method.

[0072] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A ranging-based bistatic radar clock synchronization method, characterized in that, Includes the following steps: S1. Obtain orbital information of precision orbit satellites; S2, the first radar station, and the second radar station simultaneously transmit linear frequency modulation ranging signals with positive and negative frequency modulation slopes to the precision orbit satellite target at an agreed time based on the clock of the first radar station. S3. Based on the ranging echo signal, the first radar station and the second radar station measure the single-base single-way ranging results of the first radar station and the second radar station's self-transmission and self-reception, as well as the bi-base ranging results transmitted by the first radar station and received by the second radar station, and transmitted by the second radar station and received by the first radar station. S4. Calculate the inter-station clock synchronization error based on the bi-base ranging results; S5. Determine the inter-station lag based on the single-base single-journey ranging results and the double-base ranging results; S6. Based on the inter-station clock synchronization error and inter-station lag, the clocks of the two stations are corrected to achieve high-precision clock synchronization.

2. The dual-station radar clock synchronization method according to claim 1, characterized in that, The formula for calculating the inter-station clock synchronization error Δt in step S4 is as follows: Where c is the speed of light, R 12 R is the bistatic ranging result transmitted by the first radar station and received by the second radar station. 21 The second radar station transmits the bi-base ranging results to the first radar station, which then receives them.

3. The dual-station radar clock synchronization method according to claim 1, characterized in that, The formula for judging inter-station lag in step S5 is: Among them, R 11 R 22 These are the single-base, single-way ranging results from the first and second radar stations, respectively, obtained through self-transmission and self-reception. (R) 12 The bistatic ranging results transmitted from the first radar station and received by the second radar station; (·) o This represents the true value of the distance measurement result when there is no clock synchronization error. When the bibase ranging result R 12 Greater than the true value of bibase measurement without clock synchronization error When the clock of the second radar station lags behind the clock of the first radar station, it is determined that the clock of the second radar station is behind the clock of the first radar station; when the bi-base ranging result R 12 Less than the true value of bibase measurement without clock synchronization error At that time, it was determined that the clock of the first radar station was lagging behind the clock of the second radar station.

4. The dual-station radar clock synchronization method according to claim 1, characterized in that, The orbital information in step S1 includes the azimuth and elevation information of the precise orbit satellite relative to the first radar station and the second radar station, respectively.

5. A ranging-based bistatic radar clock synchronization system, characterized in that, Includes the following modules: The orbit information acquisition module is used to acquire orbit information of satellites in precise orbits. The ranging signal transmission module is used to transmit linear frequency modulation ranging signals with positive and negative frequency modulation slopes to a precision orbit satellite target at an agreed time, with the clock of the first radar station as the reference, simultaneously through the first radar station and the second radar station. The ranging module is used to measure the single-base, one-way ranging results of the first radar station and the second radar station based on the ranging echo signals from the first radar station and the second radar station, as well as the bi-base ranging results transmitted by the first radar station and received by the second radar station, and transmitted by the second radar station and received by the first radar station. The synchronization error calculation module is used to calculate the inter-station clock synchronization error based on the bi-base ranging results; The judgment module is used to determine the inter-station lag based on the single-base single-trip ranging results and the double-base ranging results. The correction module is used to correct the clocks of two stations based on the clock synchronization error and the lag between stations, so as to achieve high-precision clock synchronization.

6. The dual-station radar clock synchronization system according to claim 5, characterized in that, The formula for calculating the inter-station clock synchronization error Δt is: Where c is the speed of light, R 12 R is the bistatic ranging result transmitted by the first radar station and received by the second radar station. 21 The second radar station transmits the bi-base ranging results to the first radar station, which then receives them.

7. The dual-station radar clock synchronization system according to claim 5, characterized in that, The formula for judging inter-station lag is: Among them, R 11 R 22 These are the single-base, single-way ranging results from the first and second radar stations, respectively, obtained through self-transmission and self-reception. (R) 12 The bistatic ranging results transmitted from the first radar station and received by the second radar station; (·) o This represents the true value of the distance measurement result when there is no clock synchronization error. When the bibase ranging result R 12 Greater than the true value of bibase measurement without clock synchronization error When the clock of the second radar station lags behind the clock of the first radar station, it is determined that the clock of the second radar station is behind the clock of the first radar station; when the bi-base ranging result R 12 Less than the true value of bibase measurement without clock synchronization error At that time, it was determined that the clock of the first radar station was lagging behind the clock of the second radar station.

8. A computer storage medium storing computer-executable instructions thereon, characterized in that, When the computer-executable instructions are executed by a computer, they are used to implement the dual-station radar clock synchronization method according to any one of claims 1-4.

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