Multi-channel radar pulse signal parameter measurement system and method

Abstract

This invention discloses a multi-channel radar pulse signal parameter measurement system and method. The implementation scheme involves: an RF signal receiving module using a local oscillator frequency sweeping method to obtain a baseband analog signal through mixing; a signal sampling module generating a baseband sampled signal sequence; a multi-channel register delay module performing register delay on the baseband sampled signal sequence to obtain a frequency-domain separated low-rate sampled signal sequence; and a time-frequency domain parameter measurement module acquiring the time-frequency domain parameters of the radar pulse signal. This invention has the capability to detect radar pulse signals over a wide bandwidth, exhibits high integration of the radar pulse signal parameter system, and uses a multi-channel register delay method to delay the baseband sampled signal sequence, obtaining a frequency-domain separated low-rate signal sequence. It also has the advantage of high measurement accuracy for simultaneously arriving radar pulse signals.

Description

Technical Field

[0001] This invention belongs to the field of radar communication technology, and further relates to a multi-channel radar pulse signal parameter measurement system and method in the field of electronic countermeasures technology. This invention can be used to measure the time-frequency domain parameters of radar pulse signals when a reconnaissance aircraft receives radar pulse signals with a wide bandwidth. Background Technology

[0002] Radar pulse signal parameter measurement is a crucial aspect of electronic reconnaissance. Acquiring the time-frequency domain parameters of intercepted radar pulse signals within the electromagnetic environment of a target area provides vital support for accurately identifying radiation source types, effectively determining their locations, and assessing threat levels. Existing radar pulse signal parameter measurement algorithms are primarily implemented using Field Programmable Gate Array (FPGA) circuits and Digital Signal Processing (DSP) chips. However, radar pulse signal parameter measurement techniques based on these high-speed devices suffer from limitations such as a narrow coverage of the measured signal frequency band, low system integration, and insufficient accuracy in measuring parameters of simultaneously arriving signals.

[0003] The 29th Research Institute of China Electronics Technology Group Corporation disclosed a digital broadband high-precision frequency measurement system and method for electromagnetic interference signals using hardware technology in its patent application "A Digital Broadband High-Precision Frequency Measurement Method and System Based on Two-Level FFT" (Application Date: April 16, 2018, Application No.: 201810337654.1, Publication No.: CN 108490255 A). The system disclosed in this patent application includes: a signal acquisition module, a signal processing module, a modulus calculation module, a threshold detection module, a signal guidance module, a finite impulse response (FIR) decimation filtering module, and a frequency precision measurement module. The system comprises the following modules: a signal acquisition module for sampling the signal using an analog-to-digital converter (AD) at zero IF, or down-converting the sampled signal to zero IF before sending it to the signal processing module; a signal processing module for splitting the received raw signal into two paths, saving one path as the raw data and performing a Fast Fourier Transform (FFT) on the other path; a modulus calculation module for performing modulus calculation on the FFT result; a threshold detection module for detecting signals that have exceeded the threshold after modulus calculation; a signal guidance module for digitally down-converting the saved raw signal to the zero IF position using the threshold-detected signal as a guide; a finite-length unit pulse (FIR) decimation filtering module for decimating and filtering the frequency-converted signal; and a frequency precision measurement module for sending the decimated and filtered baseband data to the host computer, which then performs a Fourier Transform (FFT) on the baseband data with a larger number of points than in the coarse frequency measurement, resulting in a more accurate frequency result. The shortcomings of this system are: the data processing capability of the designed signal processing module is limited, and it cannot quickly perform Fourier Transform (FFT) on large data points. It can only perform Fast Fourier Transform (FFT) on small data points in the FPGA first, and then determine whether to transmit the original sampled data to the frequency precision measurement module in the host computer based on the results of the modulus calculation module and the threshold detection module. This results in the detection system being implemented in two hardware devices, leading to low system integration.The implementation steps of the method disclosed in the patent document of this application are as follows: First, the signal is sampled by an analog-to-digital converter (A / D) at 61.44MHz zero intermediate frequency (IF) or down-converted to zero IF after sampling and then sent to the signal processing module; Second, after receiving the original signal, the signal processing module divides the signal into two paths, one path is saved as the original data, and the other path is subjected to a Fast Fourier Transform (FFT); Third, the result after the FFT is moduloed and threshold detection is performed to detect signals that have exceeded the threshold. Guided by the detected threshold signals, the saved original signal is digitally down-converted to the zero IF position, and the frequency-converted signal is decimated and filtered; Fourth, the decimated and filtered baseband data is sent to the host computer, and the host computer performs a Fast Fourier Transform (FFT) on the baseband data with a larger number of points than in the coarse frequency measurement to obtain a higher precision frequency result. The shortcomings of this method are: it directly samples the signal without separating the signal in the frequency domain, and it uses the Fast Fourier Transform (FFT) method to directly perform FFT on the data, which results in insufficient accuracy in measuring the parameters of simultaneously arriving radar pulse signals.

[0004] Xi'an University of Electronic Science and Technology disclosed an electromagnetic signal interference detection system and method based on a Field-Programmable Gate Array (FPGA) in its patent application "Electromagnetic Signal Interference Detection System and Method Based on FPGA" (application date: January 8, 2020, application number: 20201001803.6, publication number: CN 111190050A). The system disclosed in this patent application includes a signal processing module, a carrier frequency calculation module, a signal acquisition module, and a signal decision module. Specifically, the signal processing module performs zero-padding on the frame data sequence to generate a data sequence matrix, and then performs a Fourier transform on the matrix to obtain the spectrum sequence data; the carrier frequency calculation module identifies the signal to be detected based on the amplitude of the spectrum sequence and calculates the spectrum of the interference signal to be detected; the signal acquisition module assembles the continuously acquired data into an array; and the signal decision module calculates the test statistic and threshold value, determines whether the test statistic is greater than the first threshold value, and if so, passes the power spectrum mean sequence to the carrier frequency calculation module; otherwise, it sets the values ​​of all elements in the power spectrum mean sequence to zero. The shortcomings of this system are: the use of a large number of data storage units and frame sequence processing algorithms results in a complex algorithm model and low system integration. The implementation steps of the method disclosed in this patent application are: first, acquiring multiple frames of data sequences by collecting electromagnetic interference signals; second, performing a Fourier transform on the multiple frames of data sequences to obtain a power spectrum mean sequence; third, uniformly dividing and accumulating the power spectrum mean sequence to obtain a test statistic; fourth, comparing the test statistic with a threshold value to determine if the test statistic is greater than the threshold value; if so, transmitting the electromagnetic interference signal sequence to the carrier frequency calculation module; otherwise, re-receiving the electromagnetic interference signal; fifth, finding the maximum value of each element in the power spectrum mean sequence, using the electromagnetic signal corresponding to this maximum value as the interference signal to be detected, and calculating the carrier frequency of the electromagnetic signal. The shortcomings of this method are: directly performing a Fast Fourier Transform (FFT) on the data results in a narrow measurable signal bandwidth and insufficient accuracy in measuring parameters of simultaneously arriving signals. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a multi-channel radar pulse signal parameter measurement system and method. This system solves the problems of existing technologies being unable to cover wide-bandwidth signal parameter measurement and having low system integration, while also addressing the issue that existing technologies cannot meet the accuracy requirements for measuring parameters of simultaneously arriving radar pulse signals.

[0006] The specific approach to achieving the objective of this invention is as follows: The radar pulse signal parameter measurement system of this invention uses an RF signal receiving module to generate a local oscillator frequency sequence matrix for all RF signal receiving channels. The local oscillators of each RF signal receiving channel undergo frequency sweeping changes to obtain a baseband analog signal after downmixing a wide-bandwidth radar pulse signal. This enables parameter measurement of wide-bandwidth radar pulse signals, solving the problem that existing technologies cannot cover wide-bandwidth radar pulse signal parameter measurement. The multi-channel register delay module used in this invention stores the baseband sampling signal sequence of each RF signal receiving channel in each register of each RF signal receiving channel, enabling frequency domain separation of the radar pulse signal and allowing parameter measurement of simultaneously arriving signals. This solves the problem that existing technologies cannot measure the parameters of simultaneously arriving radar pulse signals. The RF signal receiving module, signal sampling module, multi-channel register delay module, and time-frequency domain parameter measurement module of this invention are all implemented on the same hardware board, solving the problem that existing technologies require two hardware devices for radar pulse signal parameter measurement, resulting in low system integration.

[0007] The technical solution to achieve the objective of this invention is:

[0008] The parameter measurement system of the present invention includes a radio frequency signal receiving module, a signal sampling module, a multi-channel register delay module, and a time-frequency domain parameter measurement module; wherein:

[0009] The radio frequency signal receiving module is used to generate the local oscillator frequency sequence matrix of all radio frequency signal receiving channels; multiply the local oscillator frequency sequence matrix X0 with the radar pulse radio frequency signal received by all radio frequency signal receiving channels for τ seconds to obtain the baseband analog signal of each radio frequency signal receiving channel; where τ represents a real value selected in the range [0,1] to meet the real-time processing requirements of the radio frequency receiving channel.

[0010] The signal sampling module is used to continuously sample the baseband analog signal received by each radio frequency signal receiving channel at the sampling frequency of the analog-to-digital converter of each radio frequency signal receiving channel, so as to obtain the baseband sampling signal sequence of each radio frequency signal receiving channel.

[0011] The multi-channel register delay module is used to register the baseband sampling signal sequence of each RF signal receiving channel in each register of all registers of each RF signal receiving channel, and to delay each baseband sampling signal sequence for a duration of k clock cycles to obtain M baseband sampling signal delay sequences, with a / f sFor each time interval, the baseband sampling signal delay sequence is sampled at low speed to obtain M low-rate sampling signal sequences corresponding to each baseband sampling signal delay sequence, where M represents the total number of registers in each RF signal receiving channel, k represents a positive integer selected from the range [0, M], a represents a positive integer selected from the range [0, M], and f... s This represents the sampling frequency value of the analog-to-digital converter in each RF signal receiving channel; an N-point inverse Fourier transform is performed on each low-rate sampled signal sequence to obtain S frequency-domain separated low-rate pulse signal sequences, where the values ​​of N and S are equal to those of M.

[0012] The time-frequency domain parameter measurement module is used to determine whether the value of each sequence point in each low-rate pulse signal sequence is greater than or equal to the detection threshold of the RF signal receiving channel. If so, the value of the low-rate pulse signal sequence at that sequence point is set to "1"; otherwise, the value of the low-rate pulse signal sequence at that sequence point is set to "0", resulting in d detection signal sequences, where the value of d is equal to M. Using a level transition extraction algorithm, the sequence numbers corresponding to the 0-1 transition points and the 1-0 transition points of each detection signal sequence are extracted respectively. All extracted sequences corresponding to the 0-1 transition points are then processed. Multiplying the minimum value in the sequence number corresponding to all 1-0 transition points by the clock period yields the estimated arrival time parameter of the radar pulse signal; multiplying the maximum value in the sequence number corresponding to all 1-0 transition points by the clock period yields the estimated end time parameter of the radar pulse signal; the difference between the estimated end time parameter and the estimated arrival time parameter is used as the estimated pulse width parameter of the radar pulse signal; performing a Fourier transform on each low-rate sampled signal sequence yields U spectrum sequences; multiplying the spectrum sequence number corresponding to the maximum spectral amplitude in each spectrum sequence by the frequency resolution yields the estimated carrier frequency parameter of the radar pulse signal, where the value of U is equal to that of M;

[0013] The specific steps of the radar pulse signal parameter measurement method of the present invention include the following:

[0014] Step 1: Obtain the baseband analog signal by frequency mixing using a local oscillator sweep frequency variation method:

[0015] Step 1.1: Generate the local oscillator frequency sequence matrix for all RF signal receiving channels as follows:

[0016]

[0017] Where X0 represents the local oscillator frequency sequence matrix, f1 represents the minimum local oscillator frequency among all RF signal receiving channels, f2 represents the maximum local oscillator frequency among all RF signal receiving channels, and n represents the total number of RF signal receiving channels. si M represents the sampling frequency of the analog-to-digital converter in the i-th radio frequency signal receiving channel.i m represents the total number of digital signal receiving channels for the i-th radio frequency signal receiving channel. i This represents the ratio of the local oscillator frequency tuning range to the local oscillator frequency variation of the i-th radio frequency signal receiving channel, where i is an integer randomly selected between [0, n].

[0018] Step 1.2: Multiply the local oscillator frequency sequence matrix X0 by the radar pulse radio frequency signal received by all radio frequency signal receiving channels for τ seconds to obtain the baseband analog signal of each radio frequency signal receiving channel; where τ represents a real value selected in the range [0,1] to meet the real-time processing requirements of the radio frequency receiving channel.

[0019] Step 2, generate the baseband sampling signal sequence:

[0020] Using the sampling frequency of the analog-to-digital converter of each RF signal receiving channel, the baseband analog signal received by that RF signal receiving channel is continuously sampled to obtain the baseband sampled signal sequence of each RF signal receiving channel;

[0021] Step 3: Apply a register delay to the baseband sampled signal sequence to obtain a frequency-domain separated low-rate sampled signal sequence.

[0022] Step 3.1: In each register of all registers of each RF signal receiving channel, store the baseband sampling signal sequence of that RF signal receiving channel. Delay each baseband sampling signal sequence for a duration of k clock cycles to obtain M baseband sampling signal delay sequences, with a / f s For each time interval, the baseband sampling signal delay sequence is sampled at low speed to obtain M low-rate sampling signal sequences corresponding to each baseband sampling signal delay sequence, where M represents the total number of registers in each RF signal receiving channel, k represents a positive integer selected from the range [0, M], a represents a positive integer selected from the range [0, M], and f... s This represents the sampling frequency value of the analog-to-digital converter for each radio frequency signal receiving channel;

[0023] Step 3.2: Perform an N-point inverse Fourier transform on each low-rate sampled signal sequence to obtain S frequency-domain separated low-rate pulse signal sequences, where the values ​​of N and S are equal to those of M.

[0024] Step 4: Obtain the time-frequency domain parameters of the radar pulse signal;

[0025] Step 4.1: Determine whether the value of each sequence point in each low-rate pulse signal sequence is greater than or equal to the detection threshold of the radio frequency signal receiving channel. If yes, set the value of the low-rate pulse signal sequence at that sequence point to "1"; otherwise, set the value of the low-rate pulse signal sequence at that sequence point to "0". This yields d detection signal sequences, where the value of d is equal to M.

[0026] Step 4.2: Using the level transition extraction algorithm, extract the sequence number corresponding to the 0-1 transition point and the sequence number corresponding to the 1-0 transition point for each detection signal sequence; multiply the minimum value among all extracted sequence numbers corresponding to 0-1 transition points by the clock period to obtain the arrival time estimation parameter of the radar pulse signal; multiply the maximum value among all sequence numbers corresponding to 1-0 transition points by the clock period to obtain the end time estimation parameter of the radar pulse signal; use the difference between the end time estimation parameter and the arrival time estimation parameter as the pulse width estimation parameter of the radar pulse signal.

[0027] Step 4.3: Perform Fourier transform on each low-rate sampled signal sequence to obtain U-channel spectrum sequences; multiply the spectrum sequence number corresponding to the maximum spectral amplitude in each spectrum sequence by the frequency resolution to obtain the carrier frequency estimation parameters of the radar pulse signal, where the value of U is equal to that of M.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] First, the radio frequency signal receiving module in the radar pulse signal parameter measurement system of the present invention obtains the baseband analog signal through the frequency sweep variation of the multi-channel local oscillator, which overcomes the shortcomings of the prior art that cannot cover wide-band radar signals, thus enabling the present invention to have the parameter measurement capability of wide-band radar pulse signals.

[0030] Secondly, in the radar pulse signal parameter measurement system of the present invention, the radio frequency signal receiving module, the signal sampling module, the multi-channel register delay module, and the time-frequency domain parameter measurement module are all implemented in the same hardware board, which overcomes the shortcomings of the prior art where the measurement system is implemented in two hardware devices, resulting in low system integration. This gives the present invention the advantage of high system integration.

[0031] Third, the radar pulse signal parameter measurement method of the present invention adopts the method of registering delayed baseband sampling signal sequence to obtain low-rate sampling signal sequence with frequency domain separation. This overcomes the shortcomings of the prior art, which does not perform frequency domain separation of the signal and has low parameter measurement accuracy for simultaneously arriving signals. As a result, the present invention has the advantage of high parameter measurement accuracy for simultaneously arriving signals. Attached image description:

[0032] Figure 1 This is a schematic diagram of the system of the present invention;

[0033] Figure 2 This is a flowchart of the method of the present invention. Detailed Implementation

[0034] To more clearly illustrate the present invention, a further detailed description is provided below in conjunction with the embodiments and accompanying drawings. Obviously, the accompanying drawings and embodiments described below are only a part of the embodiments of the present invention, and not all of them. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without any creative effort are within the scope of protection of the present invention.

[0035] Reference Figure 1 The structure of the system of the present invention will be further described below.

[0036] The system of the present invention includes a radio frequency signal receiving module, a signal sampling module, a multi-channel register delay module, and a time-frequency domain parameter measurement module. The modules are connected to each other via a bus. The radio frequency signal receiving module, the signal sampling module, the multi-channel register delay module, and the time-frequency domain parameter measurement module are all implemented in the same hardware board. The output terminal of the radio frequency signal receiving module is connected to the input terminal of the signal sampling module, the output terminal of the signal sampling module is connected to the input terminal of the multi-channel register delay module, and the output terminal of the multi-channel register delay module is connected to the input terminal of the time-frequency domain parameter measurement module.

[0037] The radio frequency signal receiving module is used to generate the local oscillator frequency sequence matrix of all radio frequency signal receiving channels; the local oscillator frequency sequence matrix X0 is multiplied by the radar pulse radio frequency signal received by all radio frequency signal receiving channels for τ seconds to obtain the baseband analog signal of each radio frequency signal receiving channel; where τ represents a real value selected in the range [0,1] to meet the real-time processing requirements of the radio frequency receiving channel.

[0038] The signal sampling module is used to continuously sample the baseband analog signal received by each radio frequency signal receiving channel at the sampling frequency of the analog-to-digital converter of each channel, so as to obtain the baseband sampled signal sequence of each radio frequency signal receiving channel.

[0039] The multi-channel register delay module stores the baseband sampled signal sequence of each RF signal receiving channel in each register of all registers of each RF signal receiving channel. It delays each baseband sampled signal sequence for a duration of k clock cycles, resulting in M ​​baseband sampled signal delay sequences, with a / f sFor each time interval, the baseband sampling signal delay sequence is sampled at low speed to obtain M low-rate sampling signal sequences corresponding to each baseband sampling signal delay sequence, where M represents the total number of registers in each RF signal receiving channel, k represents a positive integer selected from the range [0, M], a represents a positive integer selected from the range [0, M], and f... s This represents the sampling frequency value of the analog-to-digital converter in each RF signal receiving channel; an N-point inverse Fourier transform is performed on each low-rate sampled signal sequence to obtain S frequency-domain separated low-rate pulse signal sequences, where the values ​​of N and S are equal to those of M.

[0040] The time-frequency domain parameter measurement module is used to determine whether the value of each sequence point in each low-rate pulse signal sequence is greater than or equal to the detection threshold of the RF signal receiving channel. If so, the value of the low-rate pulse signal sequence at that sequence point is set to "1"; otherwise, the value of the low-rate pulse signal sequence at that sequence point is set to "0", resulting in d detection signal sequences, where the value of d is equal to M. Using a level transition extraction algorithm, the sequence numbers corresponding to the 0-1 transition points and the 1-0 transition points of each detection signal sequence are extracted respectively. From all the extracted sequence numbers corresponding to the 0-1 transition points... Multiplying the minimum value of the signal by the clock period yields the arrival time estimation parameter of the radar pulse signal; multiplying the maximum value of the sequence number corresponding to all 1-0 transition points by the clock period yields the end time estimation parameter of the radar pulse signal; the difference between the end time estimation parameter and the arrival time estimation parameter is used as the pulse width estimation parameter of the radar pulse signal; performing a Fourier transform on each low-rate sampled signal sequence yields U spectrum sequences; multiplying the spectrum sequence number corresponding to the maximum spectral amplitude in each spectrum sequence by the frequency resolution yields the carrier frequency estimation parameter of the radar pulse signal, where the value of U is equal to that of M.

[0041] Reference Figure 2 The specific steps of the method of the present invention will be further described in detail below with reference to the embodiments.

[0042] Step 1: Use local oscillator frequency sweep variation to obtain baseband analog signal through frequency mixing.

[0043] In the embodiments of the present invention, the number of radio frequency signal receiving channels selected is 4, the minimum local oscillator frequency of all radio frequency signal receiving channels is 300MHz, the maximum local oscillator frequency of all radio frequency signal receiving channels is 6GHz, and a 2s radar pulse radio frequency signal is received.

[0044] The first step is to generate the local oscillator frequency sequence matrix for all RF signal receiving channels as follows:

[0045]

[0046] Where X0 represents the local oscillator frequency sequence matrix, f1 represents the minimum local oscillator frequency among all RF signal receiving channels, f2 represents the maximum local oscillator frequency among all RF signal receiving channels, and n represents the total number of RF signal receiving channels. si M represents the sampling frequency of the analog-to-digital converter in the i-th radio frequency signal receiving channel. i m represents the total number of digital signal receiving channels for the i-th radio frequency signal receiving channel. i This represents the ratio of the local oscillator frequency tuning range to the local oscillator frequency variation of the i-th radio frequency signal receiving channel, where i is an integer randomly selected between [0, n].

[0047] Step 2: Multiply the local oscillator frequency sequence matrix X0 by the radar pulse radio frequency signal received by all radio frequency signal receiving channels for τ seconds to obtain the baseband analog signal of each radio frequency signal receiving channel; where τ represents a real value selected in the range [0,1] to meet the real-time processing requirements of the radio frequency receiving channel.

[0048] Step 2: Generate the baseband sampling signal sequence.

[0049] In the embodiments of the present invention, the sampling frequency of the analog-to-digital converter of each radio frequency signal receiving channel is 245.76MHz. The baseband analog signal received by each radio frequency signal receiving channel is continuously sampled to obtain the baseband sampling signal sequence of each radio frequency signal receiving channel.

[0050] The baseband sampling sequence is obtained by the following formula:

[0051] X i =[X i (0),X i (1 / f si ),…,X i ((L-1) / f si )]

[0052] Among them, X i X represents the baseband sampled signal sequence after the baseband analog signal received by the i-th RF signal receiving channel is sampled at equal intervals. i (0) represents the sampled value of the baseband analog signal received by the i-th RF signal receiving channel at time 0, X i (1 / f si ) represents the radar pulse signal received by the i-th radio frequency signal receiving channel at the 1 / f-th moment. si The sampled value at time τ, where L represents the length of the sampling sequence, L = round(τ·f s ), round(·) represents the rounding operation, X i ((L-1) / fs ) represents the radar pulse signal received by the i-th radio frequency signal receiving channel at the (L-1) / f-th digit. s The sampled value at time.

[0053] Step 3: Register the baseband sampled signal sequence to obtain a frequency-domain separated low-rate sampled signal sequence.

[0054] Step 1: In this embodiment of the invention, each RF signal receiving channel has 4 registers. In each register of all registers of each RF signal receiving channel, the baseband sampling signal sequence of that RF signal receiving channel is stored. Each baseband sampling signal sequence is delayed for 4 clock cycles to obtain 4 baseband sampling signal delay sequences with a time interval of 8 clock cycles. The baseband sampling signal delay sequences are then sampled at low speed to obtain 4 low-rate sampling signal sequences corresponding to each baseband sampling signal delay sequence.

[0055] Step 2: Perform an N-point inverse Fourier transform on each low-rate sampled signal sequence to obtain S frequency-domain separated low-rate pulse signal sequences, where the values ​​of N and S are equal to those of M.

[0056] The N-point inverse Fourier transform of each low-rate sampled signal sequence is obtained by the following formula:

[0057]

[0058] Where, x v (n) represents the nth element in the data sequence after the inverse Fourier transform of the v-th low-rate sampled signal sequence, N represents the number of points in the inverse Fourier transform, ∑ represents the summation operation, k represents the index of the element in the data sequence, X v (Z) represents the value of the Z-th sequence in the v-th low-rate sampled signal sequence, W N This represents the twitch factor of the inverse Fourier transform. e (·) represents an exponential operation with the natural constant e as the base, j represents the imaginary unit symbol, and π represents pi.

[0059] Step 4: Obtain the time-frequency domain parameters of the radar pulse signal.

[0060] Step 1: Determine whether the value of each sequence point in each low-rate pulse signal sequence is greater than or equal to the detection threshold of the radio frequency signal receiving channel. If yes, set the value of the low-rate pulse signal sequence at that sequence point to "1"; otherwise, set the value of the low-rate pulse signal sequence at that sequence point to "0". This yields d detection signal sequences, where the value of d is equal to M.

[0061] The detection threshold of the radio frequency signal receiving channel is obtained by the following formula:

[0062]

[0063] Where, r w σ represents the detection threshold of the w-th RF signal receiving channel. w 2 Let T represent the noise variance of the w-th RF signal receiving channel, ln() denotes the logarithmic operation with the natural constant e as the base, and T w f represents the false alarm time of the w-th RF signal receiving channel. w This represents the sampling frequency value of the analog-to-digital converter in the w-th radio frequency signal receiving channel.

[0064] Step 2: Using a level transition extraction algorithm, extract the sequence number corresponding to the 0-1 transition point and the sequence number corresponding to the 1-0 transition point for each detection signal sequence. Multiply the minimum value among all extracted sequence numbers corresponding to 0-1 transition points by the clock period to obtain the arrival time estimation parameter of the radar pulse signal. Multiply the maximum value among all sequence numbers corresponding to 1-0 transition points by the clock period to obtain the end time estimation parameter of the radar pulse signal. Use the difference between the end time estimation parameter and the arrival time estimation parameter as the pulse width estimation parameter of the radar pulse signal.

[0065] Step 3: Perform Fourier transform on each low-rate sampled signal sequence to obtain U-channel spectrum sequences; multiply the spectrum sequence number corresponding to the maximum spectral amplitude in each spectrum sequence by the frequency resolution to obtain the carrier frequency estimation parameters of the radar pulse signal, where the value of U is equal to that of M.

[0066] The frequency resolution is obtained by the following formula:

[0067]

[0068] Where Δf represents the frequency resolution, f h This indicates the sampling frequency value of the analog-to-digital converter in the radio frequency signal receiving channel.

[0069] The effects of the present invention will be further explained below with reference to simulation experiments.

[0070] 1. Simulation experimental conditions:

[0071] The hardware platform for the simulation experiment of this invention is as follows: the computer processor is an Intel i7 11700F CPU with a main frequency of 2.5GHz, the memory is 16GB, and the radio frequency transceiver board is model HJX-ADRV9009-X1.

[0072] The software platform for the simulation experiment of this invention is: Windows 10 operating system and Vivado 2018.a.

[0073] The simulation parameters of the radar pulse signals used in the simulation experiment of this invention are as follows: the carrier frequency of the pulse signal of radar 1 is 75MHz, the pulse repetition period is 16.27μs, the pulse width is 4.07μs, and the signal-to-noise ratio is 20dB; the carrier frequency of the pulse signal of radar 2 is 1.04GHz, the pulse repetition period is 16.27μs, the pulse width is 8.14μs, and the signal-to-noise ratio is 20dB; the carrier frequency of the pulse signal of radar 3 is 6.0GHz, the pulse repetition period is 16.27μs, the pulse width is 12.21μs, and the signal-to-noise ratio is 20dB; the simulation scenario is that the radar pulse signals of radar 1, radar 2, and radar 3 arrive simultaneously.

[0074] 2. Simulation content and result analysis:

[0075] The simulation experiment of this invention uses the present invention and an existing technology (a digital broadband high-precision frequency measurement method and system based on two-level FFT) to conduct 50 experiments respectively, and obtains the estimated values ​​of the time and frequency domain parameters of the radar pulse signal in the 50 experiments.

[0076] One existing technology used in the simulation experiment is the digital broadband high-precision parameter measurement method based on two-level FFT proposed by Yu Yang et al. in their published patent "A digital broadband high-precision frequency measurement method and system based on two-level FFT" (application date: 2018.04.16, application number: 201810337654.1, application publication number: CN 108490255 A).

[0077] The measurement results of the two methods are evaluated using average measurement accuracy. The average measurement accuracy of the radar pulse signal parameters is calculated using the following formula, and all results are plotted in Tables 1 and 2.

[0078]

[0079] Table 1. Comparison of average measurement accuracy of the parameters of the present invention in simulation experiments (unit: percentage)

[0080]

[0081] Table 2. Comparison of Average Measurement Accuracy of Existing Technical Methods (Unit: Percentage)

[0082]

[0083] As can be seen from Tables 1 and 2, the present invention can measure various parameters of simultaneously arriving signals with carrier frequencies ranging from 75MHz to 6GHz. Existing methods cannot measure radar pulse signals with a carrier frequency of 6GHz, indicating that the method of the present invention can measure radar pulse signals with a wider frequency band than existing methods.

[0084] As can be seen from Tables 1 and 2, the average measurement accuracy of all parameters of simultaneously arriving signals obtained by the present invention is above 99%, which is higher than the average measurement accuracy of all parameters of simultaneously arriving signals obtained by existing methods. This indicates that the present method has higher measurement accuracy for simultaneously arriving signals.

[0085] The simulation experiments above show that, under the same conditions of received radar pulse signals, the method of the present invention can obtain baseband analog signals by sweeping the frequency of multi-channel local oscillators, thus covering a wider range of radar pulse signal frequency bands. The method of the present invention obtains low-rate sampled signal sequences with frequency domain separation by using a registered delay baseband sampled signal sequence. The average measurement accuracy of the time-frequency domain parameters of the radar pulse signals arriving simultaneously is higher than that of the radar pulse signals arriving simultaneously by existing methods. It is a radar pulse parameter measurement method with higher accuracy for measuring the parameters of simultaneously arriving signals.

Claims

1. A method for measuring radar pulse signal parameters based on multiple channels, characterized in that, The baseband analog signal is obtained by frequency mixing using a local oscillator sweep frequency variation method. The baseband sampled signal sequence is then subjected to a register delay to obtain a frequency-domain separated low-rate sampled signal sequence. The steps of this measurement method include the following: Step 1: Obtain the baseband analog signal by frequency mixing using a local oscillator sweep frequency variation method: Step 1.1, the RF signal receiving module generates the local oscillator frequency sequence matrix for all RF signal receiving channels as follows: ； in, Represents the local oscillator frequency sequence matrix. This represents the minimum local oscillator frequency among all radio frequency signal receiving channels. This represents the maximum local oscillator frequency among all RF signal receiving channels, where n represents the total number of RF signal receiving channels. This represents the sampling frequency of the analog-to-digital converter in the i-th radio frequency signal receiving channel. This represents the total number of digital signal receiving channels for the i-th radio frequency signal receiving channel. This represents the ratio of the local oscillator frequency tuning range to the local oscillator frequency variation of the i-th radio frequency signal receiving channel, where i is an integer randomly selected between [0, n]. Step 1.2, the RF signal receiving module receives the local oscillator frequency sequence matrix. Received by all radio frequency signal receiving channels Multiplying the radar pulse radio frequency signals by seconds yields the baseband analog signals for each receiving channel of all radio frequency signals; where, This represents a real value selected within the range [0,1] to meet the real-time processing requirements of the RF receiving channel; Step 2, generate the baseband sampling signal sequence: The signal sampling module continuously samples the baseband analog signal received by each radio frequency signal receiving channel at the sampling frequency of the analog-to-digital converter of each channel, thereby obtaining the baseband sampled signal sequence for each radio frequency signal receiving channel. Step 3: Apply a register delay to the baseband sampled signal sequence to obtain a frequency-domain separated low-rate sampled signal sequence. Step 3.1: The multi-channel register delay module stores the baseband sampling signal sequence of each RF signal receiving channel in each register of all registers of each RF signal receiving channel, and delays each baseband sampling signal sequence for a duration of k clock cycles to obtain... A baseband sampled signal delay sequence, with For each time interval, the baseband sampled signal delay sequence is sampled at a low speed to obtain the corresponding baseband sampled signal delay sequence. A low-rate sampled signal sequence, where M represents the total number of registers in each RF signal receiving channel. This represents a positive integer selected from the range [0, M]. This represents a positive integer selected from the range [0, M]. This represents the sampling frequency value of the analog-to-digital converter for each radio frequency signal receiving channel; Step 3.2: The multi-channel register delay module performs an N-point inverse Fourier transform on each low-rate sampled signal sequence to obtain S frequency-domain separated low-rate pulse signal sequences, where the values ​​of N and S are equal to those of M. Step 4: Obtain the time-frequency domain parameters of the radar pulse signal; Step 4.1: The time-frequency domain parameter measurement module determines whether the value of each sequence point in each low-rate pulse signal sequence is greater than or equal to the detection threshold of the RF signal receiving channel. If yes, the value of the low-rate pulse signal sequence at that sequence point is set to 1; otherwise, the value of the low-rate pulse signal sequence at that sequence point is set to 0. A sequence of detection signals, wherein... The value of is equal to that of M; Step 4.2: The time-frequency domain parameter measurement module uses a level transition extraction algorithm to extract the sequence number corresponding to the 0-1 transition point and the sequence number corresponding to the 1-0 transition point for each detected signal sequence. The minimum value among all extracted sequence numbers corresponding to 0-1 transition points is multiplied by the clock period to obtain the arrival time estimation parameter of the radar pulse signal. The maximum value among all sequence numbers corresponding to 1-0 transition points is multiplied by the clock period to obtain the end time estimation parameter of the radar pulse signal. The difference between the end time estimation parameter and the arrival time estimation parameter is used as the pulse width estimation parameter of the radar pulse signal. Step 4.3: The time-frequency domain parameter measurement module performs a Fourier transform on each low-rate sampled signal sequence to obtain U-channel spectrum sequences; the spectrum sequence number corresponding to the maximum spectral amplitude in each spectrum sequence is multiplied by the frequency resolution to obtain the carrier frequency estimation parameters of the radar pulse signal, where the value of U is equal to that of M.

2. The method for measuring radar pulse signal parameters based on multiple channels according to claim 1, characterized in that, The N-point inverse Fourier transform of each low-rate sampled signal sequence described in step 3.2 is obtained by the following formula: ； in, This represents the nth element in the data sequence after the inverse Fourier transform of the v-th low-rate sampled signal sequence. This indicates the number of points to be used in the inverse Fourier transform. This represents the summation operation. Indicates the index of an element in a data sequence. This represents the value of the Z-th sequence in the v-th low-rate sampled signal sequence. This represents the twitch factor of the inverse Fourier transform. , Represented by natural constant Index-based operations. The symbol representing the imaginary unit. It represents pi (π).

3. The method for measuring radar pulse signal parameters based on multiple channels according to claim 1, characterized in that, The detection threshold of the radio frequency signal receiving channel in step 4.1 is obtained by the following formula: ； in, Indicates the first The detection threshold for each radio frequency signal receiving channel. Indicates the first The noise variance of each radio frequency signal receiving channel Represented by natural constant Logarithmic operations with base 0. Indicates the first False alarm time of each radio frequency signal receiving channel Indicates the first The sampling frequency value of the analog-to-digital converter device of each radio frequency signal receiving channel.

4. The method for measuring radar pulse signal parameters based on multiple channels according to claim 1, characterized in that, The frequency resolution mentioned in step 4.3 is obtained by the following formula: ； in, Indicates frequency resolution. This indicates the sampling frequency value of the analog-to-digital converter in the radio frequency signal receiving channel.

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