Land-based distributed radar receiving phase-coherent parameter estimation method and model

Abstract

The present application relates to a kind of land-based distributed radar receiving phase parameter estimation method and model, it is related to radar signal processing field.The method includes: the absolute value difference of the echo signal of two receiving radars is calculated;Signal difference is carried out sliding window integration, and the data sequence containing receiving phase parameter information is intercepted;The data segment after interception is preprocessed;The position of the rising edge and the falling edge of the first pulse in the processed data is calculated, and the first narrow pulse accurate position is obtained;According to the first narrow pulse accurate position, the first narrow pulse is intercepted, and the narrow pulse wideband is estimated based on the first narrow pulse.The present application can effectively reduce the amount of operation by window detection to radar signal, intercept target signal segment while removing redundant signal segment, compared with the most widely used correlation method in engineering, the calculation cost is significantly reduced and the calculation speed is doubled, and it shows superior performance in receiving phase parameter estimation.

Description

Technical Field

[0001] This invention relates to the field of radar signal processing, and specifically to a method and model for estimating coherent parameters of land-based distributed radar receivers. Background Technology

[0002] Large-aperture, high-power phased array radars are playing an increasingly important role in long-range search, tracking, surveillance, and target identification. However, with the ever-increasing demands for detection power and accuracy, the development of large-scale phased array radars faces constraints such as soaring construction costs and severely reduced mobility. Distributed fully coherent radar has emerged as a response to this need. Distributed fully coherent radar is a new type of radar following MIMO output radar. In the process of entering fully coherent operating mode, achieving receiver coherence is the first crucial step, which requires estimating the receiver coherent parameters based on the echo received by the radar antenna. This invention proposes a novel method for estimating receiver coherent parameters to address this problem.

[0003] Currently, in-depth research has been conducted on methods for estimating radar receiver coherent parameters. Existing technologies have proposed a distributed fully coherent radar coherent parameter estimation method based on correlation methods. This method derives coherent parameters by calculating the correlation coefficients of radar echo signals and statistically analyzing the location information of the maximum correlation coefficients. Another existing technology proposes a closed-loop tracking technique for fully coherent radar coherent parameters based on radar measurement information. This method defines synthesis efficiency as the optimization objective, performs pulse compression on multiple radar echo signals to calculate target range information as initial values, derives coherent parameters from these initial values, and applies them to coherent synthesis. The synthesized signal is used to calculate the synthesis efficiency of the coherent radar, and the coherent parameters are adjusted through closed-loop feedback to improve the synthesis efficiency. When the synthesis efficiency reaches a certain index value, the radar is considered to have entered coherent mode.

[0004] However, in practical engineering applications, the transmission and reception intervals of radar signals are very short, and the computing resources that can be allocated to coherent parameters on the computer deployed on the radar are limited. Therefore, stringent requirements are placed on the computational speed and computational cost of coherent parameter estimation methods, which are difficult to meet by the existing coherent parameter estimation methods mentioned above. Summary of the Invention

[0005] The technical problem to be solved by this invention is:

[0006] To address the problems of slow calculation speed, low efficiency, and high computational overhead in traditional correlation methods for estimating distributed radar coherent receiver parameters, this invention provides a coherent receiver parameter estimation method and model based on radar echo signals. This method improves the calculation speed and reduces computational overhead while meeting the accuracy requirements of receiver coherence.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for estimating coherent parameters of a land-based distributed radar receiver, characterized in that the model involved is a single-transmitter dual-receiver radar model, including:

[0009] Calculate the absolute difference between the echo signals from the two receiving radars;

[0010] The signal difference is integrated using a sliding window to extract the data sequence containing the received coherent parameter information;

[0011] Preprocess the extracted data segments;

[0012] Calculate the positions of the rising and falling edges of the first pulse in the processed data to obtain the precise position of the first narrow pulse;

[0013] The first narrow pulse is extracted based on its precise position, and the bandwidth of the narrow pulse is estimated based on the first narrow pulse.

[0014] A further technical solution of the present invention: the calculation of the absolute difference between the echo signals of the two receiving radars specifically involves:

[0015] The echo signals received by the two receiving radars are down-converted, the baseband signal loaded on the high-frequency carrier signal is extracted and sampled to obtain a digital signal, the absolute value of the two baseband signals is taken and the difference is calculated. The obtained difference signal will contain two narrow pulses with equal time width. The pulse time width is the phase coherence parameter that needs to be estimated.

[0016] A further technical solution of the present invention: the extraction of the data sequence containing the received coherent parameter information specifically includes:

[0017] Perform sliding window integration on the signal difference. The window width should be greater than the pulse width in the linear frequency modulated pulse signal transmitted by the transmitting radar. Calculate the maximum and minimum values ​​in the integration results and record their index values. Compare the two index values, calculate the state parameters, and extract the data sequence containing the received phase parameter information.

[0018] A further technical solution of the present invention: the preprocessing of the extracted data segments specifically includes:

[0019] The Gaussian kernel method is used to process the truncated data segment to obtain the processed data.

[0020] A further technical solution of the present invention: the positions of the rising and falling edges of the first pulse in the processed data are used to obtain the precise position of the first narrow pulse, specifically as follows:

[0021] Calculate the positions of the rising and falling edges of the first pulse in the processed data, perform sliding window integration on it, with the window size being 0.01 times the size of the first sliding window integration window, and store the sequence of integration results; use the mean of the integration value sequence as a threshold to determine whether the position of the window is a rising edge or a falling edge; record the window positions corresponding to the first set of rising and falling edges.

[0022] A further technical solution of the present invention: the step of truncating the first narrow pulse according to the precise position of the first narrow pulse, and estimating the narrow pulse bandwidth based on the first narrow pulse, specifically includes:

[0023] Based on the obtained window positions corresponding to the first set of rising and falling edges, the data segment containing the first narrow pulse is truncated from the data obtained by noise reduction processing, and the position of the first rising edge is calculated; the sequence of data segments containing the first narrow pulse is arranged in reverse order, and the position of the first rising edge is calculated; the coherent parameters to be estimated can be calculated from the two rising edge position parameters obtained above.

[0024] A land-based distributed radar receiver coherent parameter estimation model, characterized in that it includes:

[0025] The first calculation module is used to calculate the absolute difference between the echo signals of the two receiving radars;

[0026] The interception module is used to perform sliding window integration on the signal difference to intercept the data sequence containing the received phase parameter information;

[0027] The preprocessing module is used to preprocess the extracted data segments;

[0028] The second calculation module is used to calculate the positions of the rising and falling edges of the first pulse in the processed data, and to obtain the precise position of the first narrow pulse.

[0029] An estimation model is used to extract the first narrow pulse based on its precise position and estimate the narrow pulse bandwidth based on the first narrow pulse.

[0030] A computer system is characterized by comprising: one or more processors, and a computer-readable storage medium for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method described above.

[0031] A computer-readable storage medium is characterized by storing computer-executable instructions, which, when executed, are used to implement the above-described method.

[0032] The beneficial effects of this invention are as follows:

[0033] This invention provides a method and model for estimating the coherent parameters of a land-based distributed radar receiver. It utilizes the echo signals received by the distributed radar to extract the coherent parameters between the two radar signals. Compared with the most widely used correlation method, it has advantages such as fast computation speed and low computational overhead.

[0034] The receiving coherent parameter estimation method and model proposed in this invention can effectively estimate the receiving coherent parameters between two radar signals from the echo signals received by the distributed radar. This can be used for subsequent signal synthesis, effectively realizing the coherent superposition of the received signals, thereby significantly improving the signal-to-noise ratio of the received signals and effectively improving the execution efficiency of subsequent target tracking, target imaging and other tasks. Attached Figure Description

[0035] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0036] Figure 1 A schematic diagram of the implementation process of this invention.

[0037] Figure 2 A schematic diagram of the single-transmitter dual-receiver radar model of the present invention.

[0038] Figure 3 The simulation results of the receiving coherent parameter estimation of the present invention are shown in the MATLAB simulation diagram.

[0039] Figure 4 The performance comparison results of this invention are shown in the MATLAB simulation results. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0041] This invention employs a specific application model of a single-transmitter dual-receiver radar, as illustrated in the schematic diagram below. Figure 2As shown, transmitting radar T1 sends a linear frequency modulated pulse signal SignalLF to illuminate an airborne total reflection point target. The pulse signal is reflected by the airborne target and received by two receiving radars R1 and R2, with received signals S1 and S2 respectively. The distances between the two receiving radars and the airborne target are d1 and d2 respectively, and the corresponding time delay difference is Δt = (d1-d2) / c, where c is the speed of light.

[0042] This invention provides a method for estimating coherent parameters of a land-based distributed radar receiver, such as... Figure 1 As shown, it includes the following steps:

[0043] Step 1: First, down-convert the echo signal received by the receiving radar to extract the baseband signal loaded on the high-frequency carrier signal and sample it to obtain digital signals signal1 and signal2. Calculate the difference between the absolute values ​​of the two baseband signals. Since the target is at different distances from the two receiving radars, the positions of the linear frequency modulated pulses in the echo signals from the two radars are also different. After down-converting the two signals, taking the absolute values ​​and then subtracting them, the resulting difference signal will contain two narrow pulses with equal durations. The pulse durations are the coherent parameters that need to be estimated.

[0044] dif = |signal1| - |signal2|

[0045] Step 2: Perform sliding window integration on the signal difference (dif). The window size is win1, and the window width must be greater than the pulse width in the linear frequency modulated pulse signal transmitted by the transmitting radar to obtain the sequence integ. win1 The sequence integ is obtained through statistical analysis. win1 Find the maximum and minimum values ​​in the sequence and record their indices idx1 and idx2. Compare the sizes of idx1 and idx2, calculate the state parameter state, and extract the data sequence Y containing the received parameter information.

[0046]

[0047]

[0048]

[0049] Step 3: Preprocess the data segment Y to reduce the impact of noise. Here, the Gaussian kernel method is introduced to process the data in Y, obtaining the processed data Z. Ymax represents the maximum value in the Y sequence.

[0050]

[0051] Step 4: Calculate the positions of the rising and falling edges of the first pulse in Z. Perform sliding window integration on the data Z, with a window size of win2 (typically 0.01 times the size of win1). Store the integration result in integ. win2 The mean of the integral value sequence av integ As a threshold, determine whether the current window position represents a rising edge or a falling edge. Record the window positions loc1 and loc2 corresponding to the first set of rising and falling edges.

[0052]

[0053]

[0054] Step 5: Estimate the narrow pulse width. Based on the window positions loc1 and loc2 corresponding to the first set of rising and falling edges obtained in Step 4, truncate the Z data to obtain the data segment X containing the first narrow pulse, and calculate the position of the first rising edge on X, denoted as index1; reverse the X sequence to X′, and calculate the position of the first rising edge on X′, denoted as index2. The coherent parameter P to be estimated... cor It can be calculated using the following formula. η is a compensation coefficient, ts is the sampling period, and c is the speed of light.

[0055]

[0056] P cor =state×(length(X)-(index1+index2))×*ts*η

[0057] This invention provides a method for estimating coherent parameters of a land-based distributed radar receiver. By performing windowed detection of the radar signal, the target signal segment is extracted while redundant signal segments are removed, which can effectively reduce the amount of computation. Compared with the correlation method, which is the most widely used method in engineering, the computational overhead is significantly reduced and the computation speed is doubled, showing superior performance in estimating receiver coherent parameters.

[0058] This invention also provides a land-based distributed radar receiver coherent parameter estimation model, comprising:

[0059] The first calculation module is used to calculate the absolute difference between the echo signals of the two receiving radars;

[0060] The interception module is used to perform sliding window integration on the signal difference to intercept the data sequence containing the received phase parameter information;

[0061] The preprocessing module is used to preprocess the extracted data segments;

[0062] The second calculation module is used to calculate the positions of the rising and falling edges of the first pulse in the processed data, and to obtain the precise position of the first narrow pulse.

[0063] An estimation model is used to extract the first narrow pulse based on its precise position and estimate the narrow pulse bandwidth based on the first narrow pulse.

[0064] Simulation tests show that the method proposed in this invention is at least twice as fast as the correlation method, while reducing computational overhead by approximately 30%. Sixty-four rounds of simulation tests were conducted, and the simulation results are as follows: Figure 3 and Figure 4 As shown. In terms of computation speed, the method provided by this invention takes an average of 0.043s, while the correlation method takes an average of 0.099s, showing a significant performance improvement. In terms of detection accuracy, the method achieves the requirement that the error between the estimated coherent parameters and the true value of radar reception coherent synthesis is less than 1 / (5×B), where B refers to the radar signal bandwidth. The method provided by this invention obtains coherent parameters with an error of less than 1 / (5×B) compared to the true value, meeting the accuracy requirements of coherent synthesis.

[0065] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the scope of the technology disclosed in the present invention, and such modifications or substitutions should all be covered within the scope of protection of the present invention.

Claims

1. A method for estimating coherent parameters of a land-based distributed radar receiver, characterized in that, The model involved is a single-transmitter, dual-receiver radar model, including: Calculate the absolute difference between the echo signals from the two receiving radars; Perform a sliding window integration on the signal difference to extract the data sequence containing the received coherent parameter information; specifically: Perform sliding window integration on the signal difference, with the window width required to be greater than the pulse width in the linear frequency modulated pulse signal transmitted by the transmitting radar. Calculate the maximum and minimum values ​​in the integration results and record their index values. Compare the two index values, calculate the state parameters, and extract the data sequence containing the received phase parameter information. Preprocess the extracted data segments; Calculate the rising and falling edges of the first pulse in the processed data to obtain the precise position of the first narrow pulse; specifically: Calculate the positions of the rising and falling edges of the first pulse in the processed data, perform sliding window integration on it, with the window size being 0.01 times the size of the first sliding window integration window, and store the integration result sequence; use the mean of the integration value sequence as a threshold to determine whether the position of the window is a rising edge or a falling edge; record the window positions corresponding to the first set of rising and falling edges. The first narrow pulse is extracted based on its precise position, and the bandwidth of the narrow pulse is estimated based on the first narrow pulse; specifically: Based on the obtained window positions corresponding to the first set of rising and falling edges, the data segment containing the first narrow pulse is truncated from the data obtained by noise reduction processing, and the position of the first rising edge is calculated; the sequence of data segments containing the first narrow pulse is arranged in reverse order, and the position of the first rising edge is calculated; the coherent parameters to be estimated can be calculated from the two rising edge position parameters obtained above.

2. The method for estimating coherent parameters of a land-based distributed radar receiver according to claim 1, characterized in that, The calculation of the absolute difference between the echo signals from the two receiving radars is specifically as follows: The echo signals received by the two receiving radars are down-converted, the baseband signal loaded on the high-frequency carrier signal is extracted and sampled to obtain a digital signal, the absolute value of the two baseband signals is taken and the difference is calculated. The obtained difference signal will contain two narrow pulses with equal time width. The pulse time width is the phase coherence parameter that needs to be estimated.

3. The method for estimating coherent parameters of a land-based distributed radar receiver according to claim 1, characterized in that, The preprocessing of the extracted data segments specifically includes: The Gaussian kernel method is used to process the truncated data segment to obtain the processed data.

4. A land-based distributed radar receiver coherent parameter estimation system, characterized in that, include: The first calculation module is used to calculate the absolute difference between the echo signals of the two receiving radars; The interception module is used to perform sliding window integration on the signal difference to intercept the data sequence containing the received phase parameter information; specifically: Perform sliding window integration on the signal difference. The window width should be greater than the pulse width in the linear frequency modulated pulse signal transmitted by the transmitting radar. Calculate the maximum and minimum values ​​in the integration results and record their index values. Compare the size of the two index values, calculate the state parameters, and extract the data sequence containing the received parameter information; The preprocessing module is used to preprocess the extracted data segments; The second calculation module is used to calculate the positions of the rising and falling edges of the first pulse in the processed data, and to obtain the precise position of the first narrow pulse; specifically: Calculate the positions of the rising and falling edges of the first pulse in the processed data, perform sliding window integration on it, with the window size being 0.01 times the size of the first sliding window integration window, and store the integration result sequence; use the mean of the integration value sequence as a threshold to determine whether the position of the window is a rising edge or a falling edge; record the window positions corresponding to the first set of rising and falling edges. The estimation model is used to extract the first narrow pulse based on its precise position, and the narrow pulse bandwidth is estimated based on the first narrow pulse as follows: Calculate the positions of the rising and falling edges of the first pulse in the processed data, perform sliding window integration on it, with the window size being 0.01 times the size of the first sliding window integration window, and store the integration result sequence; use the mean of the integration value sequence as a threshold to determine whether the position of the window is a rising edge or a falling edge; record the window positions corresponding to the first set of rising and falling edges. The first narrow pulse is extracted based on its precise position, and the bandwidth of the narrow pulse is estimated based on the first narrow pulse. Specifically: Based on the obtained window positions corresponding to the first set of rising and falling edges, the data segment containing the first narrow pulse is truncated from the data obtained by noise reduction processing, and the position of the first rising edge is calculated; the sequence of data segments containing the first narrow pulse is arranged in reverse order, and the position of the first rising edge is calculated; the coherent parameters to be estimated can be calculated from the two rising edge position parameters obtained above.

5. A computer system, characterized in that... include: One or more processors, a computer-readable storage medium, for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to perform the method of any one of claims 1-3.

6. A computer-readable storage medium, characterized in that... The device stores computer-executable instructions, which, when executed, are used to implement the method described in any one of claims 1-3.

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