Radiation source positioning method and device based on distributed passive radar

Abstract

The invention provides a radiation source positioning method and device based on a distributed passive radar. The method comprises the following steps: acquiring first chirp signals intercepted by a plurality of receiving stations distributed at different positions and second chirp signals intercepted by a reference receiving station; based on the first linear frequency modulation signal and the second linear frequency modulation signal corresponding to the receiving station, a correlation method is adopted to determine a coarse time difference measurement value of the receiving station relative to the reference receiving station; calculating a time domain phase difference between the first chirp signal and the second chirp signal to determine a time difference error value of the receiving station relative to the reference receiving station; determining an accurate time difference value of the receiving station relative to the reference receiving station; and determining a spatial position coordinate of the target radiation source according to the precise time difference value corresponding to each receiving station. Through the method and the device, the finally calculated spatial position coordinates of the target radiation source are more accurate and stable.

Description

Technical Field

[0001] This application relates to the field of radiation source localization technology, and in particular to a radiation source localization method and apparatus based on distributed passive radar. Background Technology

[0002] Radiation source localization technology, as a key technology, has wide applications in navigation systems, robot tracking, and target localization. Distributed passive radar systems, as an important branch of this field, do not actively emit electromagnetic waves, possess strong anti-interference characteristics and high survivability, and have significant application value.

[0003] In a typical distributed passive radar architecture, multiple spatially separated observation stations synchronously acquire radiation source signals. The time difference between the arrival times of the radiation source signals at different observation stations is measured through cross-correlation processing, and a hyperbolic positioning equation system is established based on this. Finally, the spatial coordinates of the radiation source are determined by solving the equation system. However, because the cross-correlation method is susceptible to noise and peak jitter, the accuracy of the time difference measurement is low, leading to increased positioning errors and directly affecting the system's accuracy in locating the radiation source. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a radiation source localization method and device based on distributed passive radar, which significantly improves the time difference measurement accuracy of distributed passive radar system for linear frequency modulated radiation sources, further improves the radiation source localization accuracy of distributed passive radar, and makes the final calculated target radiation source spatial position coordinates more accurate and stable, thus solving the positioning deviation problem caused by the clock difference of receiving equipment and environmental noise interference in the prior art.

[0005] In a first aspect, embodiments of this application provide a radiation source localization method based on distributed passive radar, the radiation source localization method comprising: When the target radiation source emits a linear frequency modulated signal, the first linear frequency modulated signal intercepted by multiple receiving stations distributed at different locations is acquired, and the second linear frequency modulated signal intercepted by the reference receiving station is acquired at the same time. For each receiving station, based on the first linear frequency modulation signal and the second linear frequency modulation signal corresponding to that receiving station, the coarse time difference measurement value of that receiving station relative to the reference receiving station is determined by the correlation method. Calculate the time-domain phase difference between the first linear frequency modulated signal and the second linear frequency modulated signal, and perform linear fitting on the time-domain phase difference to determine the time difference error value of the receiving station relative to the reference receiving station; The precise time difference value of the receiving station relative to the reference receiving station is determined using the coarse time difference measurement value and the time difference error value; The spatial coordinates of the target radiation source are determined based on the precise time difference value corresponding to each receiving station.

[0006] Furthermore, the step of determining the coarse time difference measurement value of the receiving station relative to the reference receiving station using a correlation method based on the first linear frequency modulated signal and the second linear frequency modulated signal corresponding to the receiving station includes: Based on the first linear frequency modulated signal and the second linear frequency modulated signal, determine the cross-correlation function between the receiving station and the reference receiving station; The peak value of the cross-correlation function is extracted to obtain the coarse time difference measurement.

[0007] Furthermore, calculating the time-domain phase difference between the first linear frequency modulated signal and the second linear frequency modulated signal includes: Calculate the time-domain phase of the first linear frequency modulated signal and the time-domain phase of the second linear frequency modulated signal; The difference between the time-domain phase of the first linear frequency modulated signal and the time-domain phase of the second linear frequency modulated signal is defined as the time-domain phase difference.

[0008] Furthermore, the step of linearly fitting the time-domain phase difference to determine the time difference error value of the receiving station relative to the reference receiving station includes: Based on the time-domain phase difference and the time value of the multiple sampling times, the least squares method is used to fit the univariate linear relationship between the time-domain phase difference and the time value to obtain the fitting slope. The time difference error value is calculated based on the fitting slope and the frequency modulation slope of the linear frequency modulated signal emitted by the target radiation source.

[0009] Furthermore, determining the spatial coordinates of the target radiation source based on the precise time difference value corresponding to each receiving station includes: Substitute the precise time difference value corresponding to each receiving station into the pre-constructed positioning formula to obtain the target positioning formula; The target positioning formula is converted into a linear equation, and the linear equation is solved to obtain the spatial position coordinates.

[0010] Secondly, embodiments of this application also provide a radiation source locating device based on distributed passive radar, the radiation source locating device comprising: The signal acquisition module is used to acquire the first linear frequency modulation signal intercepted by multiple receiving stations located at different positions when the target radiation source emits a linear frequency modulation signal, and at the same time acquire the second linear frequency modulation signal intercepted by the reference receiving station. The coarse time difference measurement determination module is used to determine the coarse time difference measurement value of each receiving station relative to the reference receiving station by using a correlation method based on the first linear frequency modulation signal and the second linear frequency modulation signal corresponding to the receiving station. The time difference error value determination module is used to calculate the time domain phase difference between the first linear frequency modulation signal and the second linear frequency modulation signal, and to perform linear fitting on the time domain phase difference to determine the time difference error value of the receiving station relative to the reference receiving station. The precise time difference determination module is used to determine the precise time difference value of the receiving station relative to the reference receiving station using the coarse time difference measurement value and the time difference error value; The location coordinate determination module is used to determine the spatial location coordinates of the target radiation source based on the precise time difference value corresponding to each receiving station.

[0011] Furthermore, when the coarse time difference measurement determination module determines the coarse time difference measurement value of the receiving station relative to the reference receiving station using a correlation method based on the first linear frequency modulated signal and the second linear frequency modulated signal corresponding to the receiving station, the coarse time difference measurement determination module is also used for: Based on the first linear frequency modulated signal and the second linear frequency modulated signal, determine the cross-correlation function between the receiving station and the reference receiving station; The peak value of the cross-correlation function is extracted to obtain the coarse time difference measurement.

[0012] Furthermore, when calculating the time-domain phase difference between the first linear frequency modulated signal and the second linear frequency modulated signal, the time difference error value determination module is also used to: Calculate the time-domain phase of the first linear frequency modulated signal and the time-domain phase of the second linear frequency modulated signal; The difference between the time-domain phase of the first linear frequency modulated signal and the time-domain phase of the second linear frequency modulated signal is defined as the time-domain phase difference.

[0013] Thirdly, embodiments of this application also provide an electronic device, including: a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory via the bus. When the machine-readable instructions are executed by the processor, the steps of the radiation source localization method based on distributed passive radar as described above are performed.

[0014] Fourthly, embodiments of this application also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the radiation source localization method based on distributed passive radar as described above.

[0015] This application provides a radiation source localization method and apparatus based on distributed passive radar. First, when a target radiation source emits a linear frequency modulated (LFM) signal, multiple receiving stations located at different positions intercept a first LFM signal, and simultaneously, a reference receiving station intercepts a second LFM signal. Then, for each receiving station, based on the corresponding first and second LFM signals, a correlation method is used to determine the coarse time difference measurement value of that receiving station relative to the reference receiving station. The time-domain phase difference between the first and second LFM signals is calculated, and the time-domain phase difference is linearly fitted to determine the time difference error value of that receiving station relative to the reference receiving station. The coarse time difference measurement value and the time difference error value are used to determine the precise time difference value of that receiving station relative to the reference receiving station. Finally, the spatial coordinates of the target radiation source are determined based on the precise time difference value corresponding to each receiving station.

[0016] This application intercepts radiation source signals using distributed receiving stations. First, it measures the coarse time difference between each receiving station and a reference receiving station. Then, it extracts the phase difference between the intercepted signals from the receiving stations and the reference station, and performs linear fitting on the phase difference to obtain the time difference error value. Combining the coarse time difference measurement and the time difference error value yields the precise time difference. By combining coarse time difference measurement with systematic error extraction based on signal phase evolution, the accuracy of time difference measurement for linear frequency modulated radiation sources by the distributed passive radar system is significantly improved without adding additional hardware synchronization equipment. This further enhances the radiation source positioning accuracy of the distributed passive radar, making the final calculated spatial coordinates of the target radiation source more accurate and stable, thus solving the positioning deviation problem caused by clock differences in receiving equipment and environmental noise interference in existing technologies.

[0017] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart illustrating a radiation source localization method based on distributed passive radar provided in an embodiment of this application; Figure 2A schematic diagram of the distribution scenario of a target radiation source and receiving station provided in an embodiment of this application; Figure 3 A schematic diagram of the observation signal time difference between receiving station 1 and receiving station 2 provided in an embodiment of this application; Figure 4 A schematic diagram illustrating the phase difference between the observed signal from receiving station 2 and receiving station 1 after time difference compensation, provided in an embodiment of this application; Figure 5 The radiation source localization method provided in this application embodiment and the localization results of the traditional TDOA algorithm with the number of trials; Figure 6 A schematic diagram of a radiation source localization device based on distributed passive radar provided in an embodiment of this application; Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. Based on the embodiments of this application, every other embodiment obtained by those skilled in the art without inventive effort falls within the scope of protection of this application.

[0021] First, the applicable application scenarios of this application will be introduced. This application can be applied to the field of radiation source localization technology.

[0022] Radiation source localization technology, as a key technology, has wide applications in navigation systems, robot tracking, and target localization. Distributed passive radar systems, as an important branch of this field, do not actively emit electromagnetic waves, possess strong anti-interference characteristics and high survivability, and have significant application value.

[0023] Research has revealed that in a typical distributed passive radar architecture, multiple spatially separated observation stations synchronously acquire radiation source signals. The time difference between the arrival times of the radiation source signals at different observation stations is measured through cross-correlation processing, and a hyperbolic positioning equation system is established based on this. Finally, the spatial coordinates of the radiation source are determined by solving the equation system. However, the cross-correlation method is susceptible to noise and peak fluctuations, resulting in low accuracy in time difference measurement and increased positioning errors, directly affecting the system's accuracy in locating the radiation source.

[0024] Based on this, this application provides a radiation source localization method based on distributed passive radar to improve the radiation source localization accuracy of distributed passive radar, so as to make the final calculated target radiation source spatial coordinates more accurate and stable.

[0025] Please see Figure 1 , Figure 1 This is a flowchart illustrating a radiation source localization method based on distributed passive radar, provided as an embodiment of this application. Figure 1 As shown in the embodiments of this application, the radiation source localization method includes: S101: When the target radiation source emits a linear frequency modulated signal, acquire the first linear frequency modulated signal intercepted by multiple receiving stations distributed at different locations, and simultaneously acquire the second linear frequency modulated signal intercepted by a reference receiving station.

[0026] Here, the target radiation source refers to an active electromagnetic radiation device capable of transmitting linear frequency modulated (LFM) signals, which is used as the target object in this application. The LFM signal refers to a continuous wave signal emitted by the target radiation source whose frequency changes linearly with time. Multiple receiving stations are arranged in a pre-defined distributed layout at different spatial locations. Each receiving station has the capability to receive, acquire, and pre-process the LFM signal, accurately intercepting the LFM signal emitted by the target radiation source, and defining this intercepted signal as the first LFM signal. The reference receiving station is a designated base station among the multiple receiving stations. The reference receiving station can be a fixed-location station or the station with the highest signal-to-noise ratio; this application does not specifically limit this choice. The signal intercepted by the reference receiving station is defined as the second LFM signal.

[0027] Regarding step S101 above, in specific implementation, during the period when the target radiation source emits a linear frequency modulated signal, multiple receiving stations distributed in different geographical locations synchronously intercept the signal emitted by the radiation source and obtain the first linear frequency modulated signal intercepted by each receiving station; at the same time, a reference receiving station synchronously intercepts the signal emitted by the same radiation source and obtains the second linear frequency modulated signal intercepted by the reference receiving station.

[0028] Here, it is assumed that the space is distributed with Given a precisely known receiving station, the positions of the origin and the receiving station can be represented as: and As an example, choosing the first receiving station as the reference receiving station, and assuming that all receiving stations are time-frequency synchronized, then the... The first linear frequency modulated signal intercepted by a receiving station from a radiation source can be expressed by the following formula:

[0029] in, This indicates that the emitted signal from the radiation source has reached the [number]th [unit]. The latency of each receiving station, Indicates the first The fixed initial phase corresponding to each receiving station This represents the frequency modulation slope of the linear frequency modulated signal emitted by the target radiation source. , Let represent the time width and bandwidth of the linear frequency modulated (LFM) signal emitted by the target radiation source, respectively. The time-frequency matrix of the intercepted LFM signal is obtained using the short-time Fourier transform. Furthermore, it appears as a straight line on the time-frequency graph, representing the instantaneous frequency. The frequency modulation slope is obtained through linear fitting. ,bandwidth Parameters, including time width Known.

[0030] The second linear frequency modulated signal intercepted by the reference receiving station from the radiation source can be expressed by the following formula:

[0031] in, This indicates the time delay between the emitted signal from the radiation source and the arrival at the reference receiving station. This indicates the fixed initial phase corresponding to the reference receiving station.

[0032] It should be noted here that both the first and second linear frequency modulated (LFM) signals originate from the same target radiation source. The only difference between the two is the interceptor: the first LFM signal is intercepted by multiple distributed receiving stations, while the second LFM signal is intercepted by a reference receiving station. Subsequently, the phase difference and time difference will be calculated based on the two types of signals to achieve accurate positioning of the radiation source.

[0033] S102, for each receiving station, based on the first linear frequency modulation signal and the second linear frequency modulation signal corresponding to the receiving station, the coarse time difference measurement value of the receiving station relative to the reference receiving station is determined by the correlation method.

[0034] Here, the coarse time difference measurement refers to the initial time difference measurement between the arrival of the radiation source signal at the receiving station and the reference receiving station, obtained by cross-correlation calculation of the linear frequency modulated signal intercepted by the receiving station and the linear frequency modulated signal intercepted by the reference receiving station. Its accuracy is low and it is used for subsequent time difference calibration processing.

[0035] Regarding step S102 above, in specific implementation, for each receiving station, based on the first linear frequency modulated signal and the second linear frequency modulated signal corresponding to that receiving station, a coarse time difference measurement value relative to the reference receiving station is determined using a correlation method. This coarse time difference measurement value reflects the order in which signals arrive at different locations, but it is easily affected by environmental noise and equipment characteristics, and may have some deviations.

[0036] As an optional embodiment, regarding step S102 above, determining the coarse time difference measurement value of the receiving station relative to the reference receiving station using a correlation method based on the first linear frequency modulated signal and the second linear frequency modulated signal corresponding to the receiving station includes: Step 1021: Based on the first linear frequency modulated signal and the second linear frequency modulated signal, determine the cross-correlation function between the receiving station and the reference receiving station.

[0037] Regarding step 1021 above, in specific implementation, the cross-correlation function between the receiving station and the reference receiving station is determined using the first linear frequency modulated signal and the second linear frequency modulated signal. Here, continuing the example from the above steps, the first linear frequency modulated signal is expressed as... The second linear frequency modulated signal is represented as Therefore, the first Cross-correlation function between the receiving station and the reference receiving station This can be expressed by the following formula:

[0038] in, This represents the convolution operation. This indicates a conjugate operation.

[0039] Step 1022: Extract the peak value of the cross-correlation function to obtain the coarse time difference measurement value.

[0040] Regarding step 1022 above, in practical implementation, after the cross-correlation function is determined, the peak value of the cross-correlation function is extracted to obtain the coarse time difference measurement value. Here, continuing the example from the above steps, the peak value of the cross-correlation function is extracted. Cross-correlation function between the receiving station and the reference receiving station The peak value can be used to obtain the first... Each receiving station is equivalent to a coarse time difference measurement of the reference receiving station. .

[0041] Thus, according to steps 1021-1022 above, the signal intercepted by a certain receiving station is first cross-correlated with the signal intercepted by the reference receiving station to obtain a function reflecting the degree of time alignment between the two; then, the position where the value of the function reaches its maximum value is found, and the time offset corresponding to the position is the coarse time difference measurement value. By finding the point with the highest overlap of signal waveforms, the time delay between the two signals can be estimated intuitively and reliably.

[0042] S103, calculate the time-domain phase difference between the first linear frequency modulated signal and the second linear frequency modulated signal, and perform linear fitting on the time-domain phase difference to determine the time difference error value of the receiving station relative to the reference receiving station.

[0043] Here, the time difference error value is obtained by linear fitting based on the time domain phase difference between the receiving station and the reference receiving station. It is used to calibrate the coarse time difference measurement value and characterizes the deviation between the coarse time difference measurement value and the true time difference.

[0044] In specific implementation of step S103, the time-domain phase difference between the first linear frequency modulated signal and the second linear frequency modulated signal is first calculated, and the time-domain phase difference is linearly fitted to determine the time difference error value of the receiving station relative to the reference receiving station.

[0045] As an optional embodiment, regarding step S103 above, calculating the time-domain phase difference between the first linear frequency modulated signal and the second linear frequency modulated signal includes: Calculate the time-domain phase of the first linear frequency modulated signal and the time-domain phase of the second linear frequency modulated signal; determine the difference between the time-domain phase of the first linear frequency modulated signal and the time-domain phase of the second linear frequency modulated signal as the time-domain phase difference.

[0046] In the specific implementation of the above two steps, the time-domain phase of the first linear frequency modulated signal and the time-domain phase of the second linear frequency modulated signal are first calculated, and then the difference between the time-domain phase of the first linear frequency modulated signal and the time-domain phase of the second linear frequency modulated signal is determined as the time-domain phase difference.

[0047] Here, continuing with the example from the steps above, the first... Time-domain phase of the first linear frequency modulated signal at each receiving station And the time-domain phase of the second linear frequency modulated signal of the reference receiving station. They are expressed by the following formulas respectively:

[0048]

[0049] in, , Indicates the number of sampling times. This indicates the phase extraction operation.

[0050] The time-domain phase difference is expressed by the following formula:

[0051] Among them, due to It is very small, so its squared term is negligible. Therefore, the time-frequency phase difference can be expressed as: ,in Represents a constant term; As an optional embodiment, regarding step S103 above, the step of linearly fitting the time-domain phase difference to determine the time difference error value of the receiving station relative to the reference receiving station includes: Step 1031: Based on the time-domain phase difference of multiple sampling times and the time value of the multiple sampling times, the least squares method is used to fit the univariate linear relationship between the time-domain phase difference and the time value to obtain the fitting slope.

[0052] Regarding step 1031 above, in specific implementation, based on the time-domain phase difference of multiple sampling times and the time values ​​of the multiple sampling times, the least squares method is used to fit the univariate linear relationship between the time-domain phase difference and the time values ​​to obtain the fitting slope.

[0053] Here, continuing the example from the previous steps, the temporal phase difference at multiple sampling times is expressed as: The time values ​​of multiple sampling times are represented as Linear fitting was performed using the least squares method to obtain the slope. .

[0054] Step 1032: Calculate the time difference error value based on the fitting slope and the frequency modulation slope of the linear frequency modulated signal emitted by the target radiation source.

[0055] Regarding step 1032 above, in specific implementation, the ratio between the fitted slope and the frequency modulation slope of the linear frequency-modulated signal emitted by the target radiation source is used as the time difference error value. Continuing the example in the above steps, the... The time difference error between a receiving station and a reference receiving station can be expressed by the following formula:

[0056] Thus, based on steps 1031-1032 above, the time-domain phase difference calculated based on multiple different sampling times, and the specific time points corresponding to these times, a straight line that best represents the trend of change is fitted; based on the slope of the straight line, and combined with the basic modulation characteristics of the linear frequency modulated signal emitted by the target radiation source, the time difference error value caused by the difference in equipment clock between the receiving station and the reference receiving station is calculated.

[0057] S104, using the coarse time difference measurement value and the time difference error value, determine the precise time difference value of the receiving station relative to the reference receiving station.

[0058] Here, the precise time difference value refers to the high-precision time difference value between the radiation source signal arriving at the corresponding receiving station and the reference receiving station, obtained by calibrating the coarse time difference measurement value using the time difference error value. It is used to subsequently construct the positioning equation and realize the radiation source positioning.

[0059] Regarding step S104 above, in specific implementation, the precise time difference value of the receiving station relative to the reference receiving station is determined using the coarse time difference measurement value determined in step S102 and the time difference error value determined in step S103. Specifically, the precise time difference value is obtained by subtracting the coarse time difference measurement value from the time difference error value. Continuing the example in the above steps, the first... The precise time difference between a receiving station and a reference receiving station can be expressed as: .

[0060] S105, determine the spatial coordinates of the target radiation source based on the precise time difference value corresponding to each receiving station.

[0061] Regarding step S105 above, in specific implementation, after calculating the precise time difference value of each receiving station relative to the reference receiving station, the spatial coordinates of the target radiation source can be determined based on the precise time difference value corresponding to each receiving station.

[0062] As an optional embodiment, regarding step S105 above, determining the spatial coordinates of the target radiation source based on the precise time difference value corresponding to each receiving station includes: Step 1051: Substitute the precise time difference value corresponding to each receiving station into the pre-constructed positioning formula to obtain the target positioning formula.

[0063] Regarding step 1051 above, in practical implementation, the precise time difference value corresponding to each receiving station is substituted into the pre-constructed positioning formula to obtain the target positioning formula. The target positioning formula describes the relationship between spatial distance and time difference. Specifically, the target positioning formula can be expressed by the following formula:

[0064] in, It represents the speed of light.

[0065] Step 1052: Convert the target positioning formula into a linear equation and solve the linear equation to obtain the spatial position coordinates.

[0066] Regarding step 1052 above, in practical implementation, since the target positioning formula is nonlinear, it needs to be converted into a set of simpler and easier-to-process linear equations for efficient solution. Then, solving these linear equations yields the spatial coordinates of the target radiation source.

[0067] Specifically, continuing with the example in the above steps, the target localization formula is converted into a standard linear equation form. ,in: , ,

[0068] in, For the first The sum of the squares of the distances from each receiving station to the origin.

[0069] , indicating the first The distance from each receiving station to the reference receiving station.

[0070] Then, by solving the location variance in the above linear equation using the least squares method or the weighted least squares method, the spatial coordinates of the target radiation source can be obtained. Here, taking least squares as an example, the spatial coordinates are expressed as follows: .

[0071] The validity of this application is verified by the simulation results of the simulation experiment below: In a two-dimensional scene, the number of receiving stations And the coordinates of receiving station 1 are The coordinates of receiving station 2 are The coordinates of receiving station 3 are A stationary radiation source target is located at The radiation source emits a linear frequency modulated signal or a band-limited color noise signal with a pulse width of 1000ms, a pulse repetition period of 2000ms, a signal bandwidth of 1MHz, a sampling rate of 20MHz, and a signal-to-noise ratio of 20dB.

[0072] Please see Figures 2-5 , Figure 2 This is a schematic diagram illustrating the distribution layout of a target radiation source and a receiving station, provided in an embodiment of this application. Figure 3This is a schematic diagram of the observation signal time difference between receiving station 1 and receiving station 2 provided in an embodiment of this application. Figure 4 This is a schematic diagram illustrating the phase difference between the observed signal from receiving station 2 and that from receiving station 1 after time difference compensation, provided in an embodiment of this application. Figure 5 The radiation source localization method provided in this application embodiment compares the localization results with the traditional TDOA algorithm after a number of trials. Specifically, as shown... Figure 3 As shown, after cross-correlation processing, the time difference between the observed signals from receiving station 1 and receiving station 2 is 7.75 μs. However, the actual time difference between receiving station 1 and receiving station 2 is 7.7411 μs. Figure 4 As shown, time difference compensation is performed on the observed signal from receiving station 2, and the phase difference between receiving stations 1 and 2 is extracted. The phase difference slope is obtained through linear fitting, thus estimating the time difference error to be -7.9788 ns. Finally, the time difference and time difference error values ​​are measured using the cross-correlation method, yielding a time difference estimate of 7.7420 μs. The results demonstrate that the proposed method significantly improves the accuracy of time difference estimation. Figure 5 As shown, after relevant processing, the TDOA algorithm was used for positioning, and the positioning RMSE was 458.829 meters. After processing with the radiation source positioning method provided in this application, the TDOA algorithm was used for positioning, and the average positioning RMSE was 28.98 meters. According to the simulation results, the method provided in this application can improve the positioning accuracy by orders of magnitude.

[0073] The radiation source localization method based on distributed passive radar provided in this application firstly acquires a first linear frequency modulated (LFM) signal intercepted by multiple receiving stations distributed at different locations when the target radiation source emits a LFM signal, and simultaneously acquires a second LFM signal intercepted by a reference receiving station. Then, for each receiving station, based on the corresponding first LFM signal and the second LFM signal, a correlation method is used to determine the coarse time difference measurement value of the receiving station relative to the reference receiving station. The time-domain phase difference between the first LFM signal and the second LFM signal is calculated, and the time-domain phase difference is linearly fitted to determine the time difference error value of the receiving station relative to the reference receiving station. The precise time difference value of the receiving station relative to the reference receiving station is determined using the coarse time difference measurement value and the time difference error value. Finally, the spatial coordinates of the target radiation source are determined based on the precise time difference value corresponding to each receiving station.

[0074] This application intercepts radiation source signals using distributed receiving stations. First, it measures the coarse time difference between each receiving station and a reference receiving station. Then, it extracts the phase difference between the intercepted signals from the receiving stations and the reference station, and performs linear fitting on the phase difference to obtain the time difference error value. Combining the coarse time difference measurement and the time difference error value yields the precise time difference. By combining coarse time difference measurement with systematic error extraction based on signal phase evolution, the accuracy of time difference measurement for linear frequency modulated radiation sources by the distributed passive radar system is significantly improved without adding additional hardware synchronization equipment. This further enhances the radiation source positioning accuracy of the distributed passive radar, making the final calculated spatial coordinates of the target radiation source more accurate and stable, thus solving the positioning deviation problem caused by clock differences in receiving equipment and environmental noise interference in existing technologies.

[0075] Please see Figure 6 , Figure 6 This is a schematic diagram of a radiation source localization device based on distributed passive radar, provided as an embodiment of this application. Figure 6 As shown, the radiation source locating device 600 includes: The signal acquisition module 601 is used to acquire the first linear frequency modulation signal intercepted by multiple receiving stations distributed at different locations when the target radiation source emits a linear frequency modulation signal, and at the same time acquire the second linear frequency modulation signal intercepted by a reference receiving station. The coarse time difference measurement determination module 602 is used to determine the coarse time difference measurement value of each receiving station relative to the reference receiving station by using a correlation method based on the first linear frequency modulation signal and the second linear frequency modulation signal corresponding to the receiving station. The time difference error value determination module 603 is used to calculate the time domain phase difference between the first linear frequency modulation signal and the second linear frequency modulation signal, and to perform linear fitting on the time domain phase difference to determine the time difference error value of the receiving station relative to the reference receiving station. The precise time difference determination module 604 is used to determine the precise time difference value of the receiving station relative to the reference receiving station using the coarse time difference measurement value and the time difference error value; The position coordinate determination module 605 is used to determine the spatial position coordinates of the target radiation source based on the precise time difference value corresponding to each receiving station.

[0076] Furthermore, when the coarse time difference measurement determination module 602 determines the coarse time difference measurement value of the receiving station relative to the reference receiving station using a correlation method based on the first linear frequency modulated signal and the second linear frequency modulated signal corresponding to the receiving station, the coarse time difference measurement determination module 602 is also used for: Based on the first linear frequency modulated signal and the second linear frequency modulated signal, determine the cross-correlation function between the receiving station and the reference receiving station; The peak value of the cross-correlation function is extracted to obtain the coarse time difference measurement.

[0077] Furthermore, when calculating the time-domain phase difference between the first linear frequency modulated signal and the second linear frequency modulated signal, the time difference error value determination module 603 is also used for: Calculate the time-domain phase of the first linear frequency modulated signal and the time-domain phase of the second linear frequency modulated signal; The difference between the time-domain phase of the first linear frequency modulated signal and the time-domain phase of the second linear frequency modulated signal is defined as the time-domain phase difference.

[0078] Furthermore, when the time difference error value determination module 603 is used to perform linear fitting on the time domain phase difference to determine the time difference error value of the receiving station relative to the reference receiving station, the time difference error value determination module 603 is also used to: Based on the time-domain phase difference and the time value of the multiple sampling times, the least squares method is used to fit the univariate linear relationship between the time-domain phase difference and the time value to obtain the fitting slope. The time difference error value is calculated based on the fitting slope and the frequency modulation slope of the linear frequency modulated signal emitted by the target radiation source.

[0079] Furthermore, when determining the spatial coordinates of the target radiation source based on the precise time difference value corresponding to each receiving station, the position coordinate determination module 605 is also used for: Substitute the precise time difference value corresponding to each receiving station into the pre-constructed positioning formula to obtain the target positioning formula; The target positioning formula is converted into a linear equation, and the linear equation is solved to obtain the spatial position coordinates.

[0080] Please see Figure 7 , Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 7 As shown, the electronic device 700 includes a processor 710, a memory 720, and a bus 730.

[0081] The memory 720 stores machine-readable instructions executable by the processor 710. When the electronic device 700 is running, the processor 710 communicates with the memory 720 via the bus 730. When the machine-readable instructions are executed by the processor 710, they can perform the operations described above. Figure 1The specific implementation of the radiation source localization method based on distributed passive radar in the method embodiment shown can be found in the method embodiment, and will not be repeated here.

[0082] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can perform the above-described actions. Figure 1 The specific implementation of the radiation source localization method based on distributed passive radar in the method embodiment shown can be found in the method embodiment, and will not be repeated here.

[0083] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0084] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0085] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0086] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0087] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0088] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The scope of protection of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A radiation source localization method based on distributed passive radar, characterized in that, The radiation source localization method includes: When the target radiation source emits a linear frequency modulated signal, the first linear frequency modulated signal intercepted by multiple receiving stations distributed at different locations is acquired, and the second linear frequency modulated signal intercepted by the reference receiving station is acquired at the same time. For each receiving station, based on the first linear frequency modulation signal and the second linear frequency modulation signal corresponding to that receiving station, the coarse time difference measurement value of that receiving station relative to the reference receiving station is determined by the correlation method. Calculate the time-domain phase difference between the first linear frequency modulated signal and the second linear frequency modulated signal, and perform linear fitting on the time-domain phase difference to determine the time difference error value of the receiving station relative to the reference receiving station; The precise time difference value of the receiving station relative to the reference receiving station is determined using the coarse time difference measurement value and the time difference error value; The spatial coordinates of the target radiation source are determined based on the precise time difference value corresponding to each receiving station.

2. The radiation source localization method according to claim 1, characterized in that, The determination of the coarse time difference measurement value of the receiving station relative to the reference receiving station using a correlation method based on the first linear frequency modulated signal and the second linear frequency modulated signal corresponding to the receiving station includes: Based on the first linear frequency modulated signal and the second linear frequency modulated signal, determine the cross-correlation function between the receiving station and the reference receiving station; The peak value of the cross-correlation function is extracted to obtain the coarse time difference measurement.

3. The radiation source localization method according to claim 1, characterized in that, The calculation of the time-domain phase difference between the first linear frequency modulated signal and the second linear frequency modulated signal includes: Calculate the time-domain phase of the first linear frequency modulated signal and the time-domain phase of the second linear frequency modulated signal; The difference between the time-domain phase of the first linear frequency modulated signal and the time-domain phase of the second linear frequency modulated signal is defined as the time-domain phase difference.

4. The radiation source localization method according to claim 1, characterized in that, The step of linearly fitting the time-domain phase difference to determine the time difference error value of the receiving station relative to the reference receiving station includes: Based on the time-domain phase difference and the time value of the multiple sampling times, the least squares method is used to fit the univariate linear relationship between the time-domain phase difference and the time value to obtain the fitting slope. The time difference error value is calculated based on the fitting slope and the frequency modulation slope of the linear frequency modulated signal emitted by the target radiation source.

5. The radiation source localization method according to claim 1, characterized in that, The step of determining the spatial coordinates of the target radiation source based on the precise time difference value corresponding to each receiving station includes: Substitute the precise time difference value corresponding to each receiving station into the pre-constructed positioning formula to obtain the target positioning formula; The target positioning formula is converted into a linear equation, and the linear equation is solved to obtain the spatial position coordinates.

6. A radiation source localization device based on distributed passive radar, characterized in that, The radiation source locating device includes: The signal acquisition module is used to acquire the first linear frequency modulation signal intercepted by multiple receiving stations located at different positions when the target radiation source emits a linear frequency modulation signal, and at the same time acquire the second linear frequency modulation signal intercepted by the reference receiving station. The coarse time difference measurement determination module is used to determine the coarse time difference measurement value of each receiving station relative to the reference receiving station by using a correlation method based on the first linear frequency modulation signal and the second linear frequency modulation signal corresponding to the receiving station. The time difference error value determination module is used to calculate the time domain phase difference between the first linear frequency modulation signal and the second linear frequency modulation signal, and to perform linear fitting on the time domain phase difference to determine the time difference error value of the receiving station relative to the reference receiving station. The precise time difference determination module is used to determine the precise time difference value of the receiving station relative to the reference receiving station using the coarse time difference measurement value and the time difference error value; The location coordinate determination module is used to determine the spatial location coordinates of the target radiation source based on the precise time difference value corresponding to each receiving station.

7. The radiation source locating device according to claim 6, characterized in that, When the coarse time difference measurement determination module is used to determine the coarse time difference measurement value of the receiving station relative to the reference receiving station based on the first linear frequency modulated signal and the second linear frequency modulated signal corresponding to the receiving station using a correlation method, the coarse time difference measurement determination module is further used for: Based on the first linear frequency modulated signal and the second linear frequency modulated signal, determine the cross-correlation function between the receiving station and the reference receiving station; The peak value of the cross-correlation function is extracted to obtain the coarse time difference measurement.

8. The radiation source locating device according to claim 6, characterized in that, When calculating the time-domain phase difference between the first linear frequency modulated signal and the second linear frequency modulated signal, the time difference error determination module is further configured to: Calculate the time-domain phase of the first linear frequency modulated signal and the time-domain phase of the second linear frequency modulated signal; The difference between the time-domain phase of the first linear frequency modulated signal and the time-domain phase of the second linear frequency modulated signal is defined as the time-domain phase difference.

9. An electronic device, characterized in that, include: The device includes a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory via the bus. The machine-readable instructions are executed by the processor to perform the steps of the radiation source localization method based on distributed passive radar as described in any one of claims 1 to 5.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the steps of the radiation source localization method based on distributed passive radar as described in any one of claims 1 to 5.

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