CN111198355B - PCR echo signal processing system and method based on FPGA - Google Patents
PCR echo signal processing system and method based on FPGA Download PDFInfo
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- CN111198355B CN111198355B CN202010040051.2A CN202010040051A CN111198355B CN 111198355 B CN111198355 B CN 111198355B CN 202010040051 A CN202010040051 A CN 202010040051A CN 111198355 B CN111198355 B CN 111198355B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/28—Details of pulse systems
- G01S7/285—Receivers
- G01S7/292—Extracting wanted echo-signals
- G01S7/2923—Extracting wanted echo-signals based on data belonging to a number of consecutive radar periods
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/28—Details of pulse systems
- G01S7/285—Receivers
- G01S7/32—Shaping echo pulse signals; Deriving non-pulse signals from echo pulse signals
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
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Abstract
The invention discloses a PCR echo signal processing system and method based on FPGA, and the system comprises a data acquisition module, a pulse compression module, a moving target filtering module, a moving target detection module and a constant false alarm module. The method comprises the following steps: receiving a radar echo signal; (2) preprocessing the echo signal; (3) performing pulse compression on the preprocessed echo signals; (4) generating a Doppler frequency spectrum sequence; (5) calculating the speed of the moving target; (6) filtering out static targets; and (7) calculating the position of the moving target. The system of the invention has the advantages of easy development and normal work under the condition of high sampling rate; the method has the advantage of measuring the speed and the position of the moving target in the echo signals with different lengths.
Description
Technical Field
The invention belongs to the technical Field of Radar communication, and further relates to a Pulse Compression Radar (PCR) echo signal processing system and method based on a Field Programmable Gate Array (FPGA). The method can be used for extracting the position information and the speed information of the target in the echo signal received by the pulse compression radar PCR.
Background
The extraction of target position information and speed information in a pulse compression radar echo signal generally adopts a solution scheme that an FPGA chip with high real-time performance and high stability is used as a reference, and the FPGA is developed by using a Hardware Description Language (HDL), but the development mode has the defects of difficult modification and poor flexibility. Along with the rapid development of computer technology, computers are widely applied in the technical field of radar digital signal processing, and the use of computers for radar signal processing has the advantages of high development speed, high flexibility, convenience in modification and the like, but the radar signal processing generally has high data volume and complex algorithm complexity, so that the cost of a radar signal processing system can be increased, and the real-time performance of the radar signal processing system can be reduced. The System Generator is used for System modeling and algorithm realization, and partial research results are already available.
A patent document applied by Nanjing university of science and engineering, "a Python-based radar signal processing system and method" (application date: 2018.12.24, application number: 201811583862.6, application publication number: CN 109633567A) discloses a Python-based pulse compression radar echo signal processing system and method. The system comprises a data acquisition module, a modulation signal generation module, a synchronous control module, a USB communication module, a signal processing module and a control display module. The data acquisition module is used for acquiring echo signals of the pulse compression radar and performing analog-to-digital conversion; the modulation signal generation module is used for generating a sawtooth signal and further modulating a transmitting signal; the synchronous control module is used for generating a pulse signal synchronous with the sawtooth signal and controlling N acquisition channels in the data acquisition module to synchronously acquire echo signals; the USB communication module transmits the data acquired by the data acquisition module to the signal processing module; the signal processing module is used for carrying out signal processing on the pulse compression radar echo signal, acquiring position information and speed information of a target and transmitting the position information and the speed information to the control display module; and the control display module is used for controlling the pulse compression radar echo signal processing system to be turned on and turned off, displaying target information and carrying out user identity authentication. The system has the following disadvantages: the USB communication module and the signal processing module need to have the capability of high-speed data transmission, which increases the cost of the system.
The implementation steps of the method disclosed in the patent literature applied by Nanjing university of science and engineering are as follows: firstly, a data acquisition module is controlled by a synchronous control module and a control display module to acquire pulse compression radar echo signals and convert analog signals into digital signals; secondly, transmitting and caching the digital signals obtained in the first step through a USB communication module, and transmitting the signals to a signal processing module when cached data reaches a set value; thirdly, the signal processing module carries out filtering, data rearrangement, clutter suppression, moving target detection, constant false alarm, target condensation and angle measurement on the received signals to obtain distance and speed information of the targets; and fourthly, transmitting the distance and speed information obtained in the third step to a control display module for displaying, and finishing the processing of the pulse compression radar echo signal. The method has the following defects: when the sampling frequency of the data acquisition module is too high, the USB communication module and the signal processing module cannot work normally due to too large data volume, and the position and the speed of a target cannot be accurately measured from a pulse compression radar echo signal.
Xuyin hui et al proposed an FPGA-based digital signal processing system and method in its published article "multi-channel pulse compression programming based on FPGA" (Computer Engineering and Applications 2011 341-345). The system comprises a data acquisition module, a digital down-conversion module, a pulse compression module, a type conversion module and a target information calculation module. The data acquisition module acquires radar echo signals through the data acquisition board card; the digital down-conversion module is used for performing digital down-conversion operation on the radar echo signal; the pulse compression module is used for performing fixed-point pulse compression processing on the data after the down-conversion; the type conversion module is used for converting the data after pulse compression into single-precision floating point numbers; and the target information calculation module is used for calculating the position information of the target. The system has the defects that the pulse compression module can only process data with fixed point number for pulse compression processing, and when the data point number changes, the pulse compression processing can not be realized.
The implementation steps of the method disclosed in the published article by pauli showy et al are as follows: firstly, radar echo signals are collected through a data collection module; secondly, performing digital down-conversion operation on the acquired radar echo signals to obtain zero intermediate frequency complex signals; thirdly, performing fixed-point pulse compression processing on the data after the digital down-conversion; fourthly, converting the pulse compressed signal into a single-precision floating point number; fifthly, the converted signals are used for calculating the speed information and the position information of the target through a target calculating module. The method has the defects that the position of the moving target cannot be kept constant when being calculated, and the deviation of a detection result and the real position of the target can be caused.
Disclosure of the invention
The invention aims to provide a pulse compression radar PCR echo signal processing system and method based on a field programmable gate array FPGA (field programmable gate array), aiming at overcoming the problems that the position and the speed of a target cannot be accurately measured due to overhigh signal sampling rate, the traditional FPGA development mode has difficulty in modification, poor flexibility and the like.
The specific idea for realizing the purpose of the invention is as follows: the length of the sampling data has a linear relation with the sampling rate, when the sampling rate is higher, the number of the sampling data points is increased, and the data sampled at the high sampling rate is subjected to down-sampling, so that the length of the data can be effectively shortened; the graphic development mode of the FPGA has the characteristics of convenience in modification and high flexibility, and the system is developed by adopting the graphic development mode, so that the problems of difficulty in modification and lack of flexibility of the traditional development mode can be solved.
The pulse compression radar PCR echo signal processing system comprises a data acquisition module, a pulse compression module, a moving target filtering module, a moving target detection module, a constant false alarm module and a signal preprocessing module, wherein all the modules are developed in a graphical mode; wherein:
the data acquisition module is used for taking a pulse compression signal transmitted by the pulse compression radar for the first time as a reference signal, recording the time for finishing transmitting the reference signal as the pulse width of the reference signal, and taking the sampling frequency f as the echo signal of the pulse compression radar received in real time after the pulse compression radar transmits the pulse compression signal for the first time as the sampling frequency f s1 Sampling to obtain echo signals, wherein f s1 ＞500MHz；
The signal preprocessing module comprises: the device comprises a digital down-conversion module, a down-sampling module, an echo signal supplementing module, a Hamming window generating module, a Hamming window signal supplementing module, a reference signal preprocessing module and a Hamming window module; the digital down-conversion module is used for performing digital down-conversion processing on the echo signal to obtain a zero-intermediate-frequency complex signal; carrying out zero intermediate frequency complex signal
Multiple down-sampling to obtain a length of
Wherein denotes a multiplication operation, f s2 Indicating the frequency of sampling the zero intermediate frequency complex signal, and L indicating the length of the echo signal; echo signal supplementing module for supplementing tail of down-sampling echo signal
Zero-counting to obtain a preprocessed echo signal, wherein ceil represents an upward rounding operation, log 2 Denotes base 2 logarithmic operation, L 1 Representing the length of the down-sampled echo signal; a Hamming window generation module for generating a window having a width of
Wherein τ represents a pulse width of the reference signal; hamming window signal supplementing module for supplementing the end of Hamming window signal
Zero, obtaining a Hamming window signal of the complementary length, wherein L w Representing the length of a hamming window signal; a reference signal preprocessing module, configured to process the reference signal by using the same processing method as that used for processing the echo signal in this step, so as to obtain a reference signal with a length that is completely compensated; a Hamming window module for multiplying the length-padded reference signal by the length-padded Hamming window signal,obtaining a preprocessed reference signal;
the pulse compression module includes: the device comprises an echo signal Fourier transform module, a reference signal Fourier transform module, a conjugate multiplication module and an inverse Fourier transform module; the echo signal Fourier transform module is used for performing Fourier transform on the preprocessed echo signal to obtain a frequency domain echo signal; the reference signal Fourier transform module is used for carrying out Fourier transform on the preprocessed reference signal to obtain a frequency domain reference signal; the conjugate multiplication module is used for performing conjugate processing on the frequency domain reference signal to obtain a conjugate frequency domain reference signal; multiplying the frequency domain echo signal by the conjugate frequency domain reference signal to obtain a pulse compression frequency domain signal; the inverse Fourier transform module is used for performing inverse Fourier transform on the pulse compression frequency domain signal to obtain a pulse compression time domain signal;
the moving target filtering module is used for subtracting the pulse compression time domain signal between the previous adjacent transmissions from the pulse compression time domain signal between the current adjacent transmissions of the pulse compression radar to obtain a filtering signal for filtering the static target;
the moving target detection module comprises: the device comprises a pulse storage module, a pulse transformation module, a parallel Fourier transformation module and a speed calculation module; the pulse storage module is used for sequentially splicing pulse compression time domain signals continuously transmitted by the pulse compression radar for N times to obtain a signal sequence, wherein the value of N is a positive integer greater than 4; a pulse conversion module for sequentially converting the signal sequence into NxL 2 Matrix X of 1 Wherein L is 2 Representing the length of the pulse compressed time domain signal; a parallel Fourier transform module for transforming the matrix X 1 Each column of (A) is Fourier transformed to obtain a matrix X 2 (ii) a Will matrix X 2 All elements in the matrix are subjected to modulus processing to obtain a matrix X 3 (ii) a Will matrix X 3 All elements in each row are added to form a Doppler frequency spectrum sequence; the velocity calculation module is used for finding out the element maximum value in the Doppler frequency spectrum sequence and taking the Doppler frequency value corresponding to the maximum value as the velocity of the moving target;
and the constant false alarm module is used for carrying out constant false alarm detection on the filtering signal to obtain the position of the moving target.
The invention relates to a pulse compression radar PCR echo signal processing method based on a field programmable gate array FPGA, which comprises the following specific steps:
step 1, receiving a pulse compression radar PCR echo signal in real time:
the data acquisition module takes a pulse compression signal transmitted by the pulse compression radar for the first time as a reference signal, the time for completing the transmission of the reference signal is recorded as the pulse width of the reference signal, and a pulse compression radar echo signal received in real time after the pulse compression radar transmits the pulse compression signal for the first time takes the sampling frequency as f s1 Sampling to obtain echo signals, wherein f s1 ＞500MHz；
Step 2, preprocessing the echo signal and the reference signal:
a digital down-conversion module in the signal preprocessing module performs digital down-conversion processing on the echo signal to obtain a zero-intermediate-frequency complex signal;
the down-sampling module in the signal preprocessing module carries out zero intermediate frequency complex signal
Multiple down-sampling to obtain the length of
Wherein denotes a multiplication operation, f s2 Indicating the frequency of sampling the zero intermediate frequency complex signal, and L indicating the length of the echo signal;
echo signal supplementing module in signal preprocessing module supplements echo signal at tail end of down-sampling echo signal
Zero, obtaining a preprocessed echo signal, wherein ceil represents an upward rounding operation, log 2 Denotes base 2 logarithmic operation, L 1 Representing the length of the down-sampled echo signal;
signal pre-processingThe Hamming window generation module in the physics module generates a window having a width of
Wherein τ represents a pulse width of the reference signal;
hamming window signal supplementing module in signal preprocessing module supplements at the tail of Hamming window signal
Zero, obtaining a hamming window signal of a complete length, wherein L w Representing the length of a hamming window signal;
a reference signal preprocessing module in the signal preprocessing module processes the reference signal by adopting the same processing method for the echo signal as the method for processing the echo signal in the step to obtain a reference signal with a complete length; a Hamming window module in the signal preprocessing module multiplies the length-compensated reference signal by the length-compensated Hamming window signal to obtain a preprocessed reference signal;
step 3, performing pulse compression on the preprocessed echo signals:
an echo signal Fourier transform module in the pulse compression module performs Fourier transform on the preprocessed echo signal to obtain a frequency domain echo signal;
a reference signal Fourier transform module in the pulse compression module performs Fourier transform on the preprocessed reference signal to obtain a frequency domain reference signal;
a conjugate multiplication module in the pulse compression module carries out conjugate processing on the frequency domain reference signal to obtain a conjugate frequency domain reference signal; multiplying the frequency domain echo signal by the conjugate frequency domain reference signal to obtain a pulse compression frequency domain signal;
an inverse Fourier transform module in the pulse compression module performs inverse Fourier transform on the pulse compression frequency domain signal to obtain a pulse compression time domain signal;
step 4, generating a Doppler frequency spectrum sequence:
a pulse storage module in the moving target detection module sequentially splices pulse compression time domain signals continuously transmitted by a pulse compression radar for N times to obtain a signal sequence, wherein the value of N is a positive integer greater than 4;
the pulse storage module in the moving target detection module converts the signal sequence in sequence according to the line to obtain NxL 2 Matrix X of 1 Wherein L is 2 Representing the length of the pulse compressed time domain signal;
a parallel Fourier transform module in the moving target detection module converts the matrix X 1 Each column of (A) is Fourier transformed to obtain a matrix X 2 (ii) a Will matrix X 2 All elements in the matrix are subjected to modulus processing to obtain a matrix X 3 (ii) a Will matrix X 3 All elements in each row are added to form a Doppler frequency spectrum sequence;
step 5, a velocity calculation module in the moving target detection module finds out the element maximum value in the Doppler frequency spectrum sequence, and the Doppler frequency value corresponding to the maximum value is taken as the velocity of the moving target;
step 6, performing moving target filtering on the pulse compression time domain signal:
the moving target filtering module subtracts the pulse compression time domain signal between the previous adjacent transmissions from the pulse compression time domain signal between the current adjacent transmissions of the pulse compression radar to obtain a filtering signal for filtering the static target;
and 7, carrying out constant false alarm detection on the filtered signal by the constant false alarm module to obtain the position of the moving target.
Compared with the prior art, the invention has the following advantages:
firstly, the pulse compression radar echo signal processing system is developed in a graphical development mode, so that the problems of difficulty in modification and lack of flexibility of the development mode in the prior art are solved, and the pulse compression radar echo signal processing system has the advantage of easiness in development.
Secondly, because the signal preprocessing module in the pulse compression radar echo signal processing system can perform down-sampling processing on the echo signal acquired by the data acquisition module and the reference signal, the problem that the USB communication module and the signal processing module cannot normally work due to too large data volume when the sampling frequency of the data acquisition module is too high in the existing system is solved, and the pulse compression radar echo signal processing system has the advantage of normally working under the condition of high sampling rate.
Thirdly, because the echo signal after down sampling is subjected to signal completion processing in the echo signal processing method of the pulse compression radar, the problem that only echo signals with fixed lengths can be processed in the prior art is solved, and the method has the advantage that the speed and the position of a moving target in the echo signals can be measured under the condition that the lengths of the echo signals are different.
Description of the drawings:
FIG. 1 is a block diagram of the system of the present invention;
FIG. 2 is a flow chart of the method of the present invention.
The specific implementation mode is as follows:
the invention is further described below with reference to the accompanying drawings.
The structure of the system of the present invention will be further described with reference to fig. 1.
The System comprises a data acquisition module, a signal preprocessing module, a pulse compression module, a moving target filtering module, a moving target detection module and a constant false alarm module, wherein all the modules are developed by adopting a System Generator-based graphical development mode, the modules are connected in a bus mode, the output end of the data acquisition module is connected with the input end of the signal preprocessing module, the output end of the signal preprocessing module is connected with the input end of the pulse compression module, the output end of the pulse compression module is respectively connected with the input ends of the moving target filtering module and the moving target detection module, and the output end of the moving target filtering module is connected with the input end of the constant false alarm module.
The data acquisition module is used for taking a pulse compression signal transmitted by the pulse compression radar for the first time as a reference signal, recording the time for completing the transmission of the reference signal as the pulse width of the reference signal, and taking the sampling frequency f as the echo signal of the pulse compression radar received in real time after the pulse compression radar transmits the pulse compression signal for the first time as the sampling frequency s1 Sampling to obtain echo signal, wherein f s1 ＞500MHz。
The signal preprocessing module comprises: number ofThe device comprises a down-conversion module, a down-sampling module, an echo signal supplementing module, a Hamming window generating module, a Hamming window signal supplementing module, a reference signal preprocessing module and a Hamming window module; the digital down-conversion module is used for performing digital down-conversion processing on the echo signal to obtain a zero intermediate frequency complex signal; carrying out zero intermediate frequency complex signal
Multiple down-sampling to obtain a length of
Wherein denotes a multiplication operation, f s2 Indicating the frequency of sampling the zero intermediate frequency complex signal, and L indicating the length of the echo signal; echo signal supplementing module supplements at tail of down-sampling echo signal
Zero, obtaining a preprocessed echo signal, wherein ceil represents an upward rounding operation, log 2 Denotes base 2 logarithmic operation, L 1 Representing the length of the down-sampled echo signal; a Hamming window generation module for generating a window having a width of
Wherein τ represents a pulse width of the reference signal; hamming window signal supplementing module for supplementing the end of Hamming window signal
Zero, obtaining a Hamming window signal of the complementary length, wherein L w Representing the length of a hamming window signal; a reference signal preprocessing module, configured to process the reference signal by using the same processing method as that used for processing the echo signal in this step, so as to obtain a reference signal with a length equal to the length of the echo signal; and the Hamming window module is used for multiplying the reference signal with the filling length by the Hamming window signal with the filling length to obtain the preprocessed reference signal.
The pulse compression module includes: the device comprises an echo signal Fourier transform module, a reference signal Fourier transform module, a conjugate multiplication module and an inverse Fourier transform module; the echo signal Fourier transform module is used for performing Fourier transform on the preprocessed echo signal to obtain a frequency domain echo signal; the reference signal Fourier transform module is used for carrying out Fourier transform on the preprocessed reference signal to obtain a frequency domain reference signal; the conjugate multiplication module is used for performing conjugate processing on the frequency domain reference signal to obtain a conjugate frequency domain reference signal; multiplying the frequency domain echo signal by the conjugate frequency domain reference signal to obtain a pulse compression frequency domain signal; and the inverse Fourier transform module is used for performing inverse Fourier transform on the pulse compression frequency domain signal to obtain a pulse compression time domain signal.
And the moving target filtering module is used for subtracting the pulse compression time domain signal between the previous adjacent transmissions from the pulse compression time domain signal between the current adjacent transmissions of the pulse compression radar to obtain a filtering signal for filtering the static target.
The moving target detection module comprises: the device comprises a pulse storage module, a pulse transformation module, a parallel Fourier transformation module and a speed calculation module; the pulse storage module is used for sequentially splicing pulse compression time domain signals continuously transmitted by the pulse compression radar for N times to obtain a signal sequence, wherein the value of N is a positive integer greater than 4; a pulse conversion module for converting the signal sequence into NxL signal sequence in sequence 2 Matrix X of 1 Wherein L is 2 Representing the length of the pulse compressed time domain signal; a parallel Fourier transform module for transforming the matrix X 1 Performing Fourier transform on each column of the matrix to obtain a matrix X 2 (ii) a Will matrix X 2 All elements in the matrix are subjected to modulus processing to obtain a matrix X 3 (ii) a Will matrix X 3 All elements in each row are added to form a Doppler frequency spectrum sequence; and the velocity calculation module is used for finding out the maximum value of the element in the Doppler frequency spectrum sequence and taking the Doppler frequency value corresponding to the maximum value as the velocity of the moving target.
And the constant false alarm module is used for carrying out constant false alarm detection on the filtering signal to obtain the position of the moving target.
The method of the invention is further described with reference to figure 2.
Step 1, receiving a pulse compression radar PCR echo signal in real time:
the data acquisition module takes a pulse compression signal transmitted by the pulse compression radar for the first time as a reference signal, the time for finishing transmitting the reference signal is recorded as the pulse width of the reference signal, and a pulse compression radar echo signal received in real time after the pulse compression radar transmits the pulse compression signal for the first time is taken as the sampling frequency f s1 Sampling to obtain echo signal, wherein f s1 ＞500MHz。
Step 2, preprocessing the echo signal and the reference signal:
and a digital down-conversion module in the signal preprocessing module performs digital down-conversion processing on the echo signal to obtain a zero intermediate frequency complex signal.
The down-sampling module in the signal preprocessing module carries out zero intermediate frequency complex signal
Multiple down-sampling to obtain a length of
Wherein denotes a multiplication operation, f s2 Indicating the frequency at which the zero intermediate frequency complex signal is sampled and L the length of the echo signal. The zero intermediate frequency complex signal is carried out
The down-sampling process is implemented according to the following formula:
wherein y (n) represents the nth element in the echo signal after down sampling, and the value range of n is 0 to L 1 1, x (m) denotes the m-th element in the complex signal at zero intermediate frequency, ceil denotes the ceiling operation.
Echo signal supplementing module in signal preprocessing module supplements echo signal at tail end of down-sampling echo signal
Zero, obtaining a preprocessed echo signal, wherein log 2 Denotes base 2 logarithmic operation, L 1 Representing the length of the down-sampled echo signal.
The Hamming window generation module in the signal preprocessing module generates a signal with a width of
Wherein τ represents the pulse width of the reference signal.
Hamming window signal supplementing module in signal preprocessing module supplements at tail of Hamming window signal
Zero, obtaining a Hamming window signal of the complementary length, wherein L w Representing the length of the hamming window signal.
The reference signal preprocessing module in the signal preprocessing module processes the reference signal by the same processing method as the echo signal processing method described above in this step, so as to obtain a reference signal with a length that is supplemented.
And a Hamming window module in the signal preprocessing module multiplies the length-compensated reference signal by the length-compensated Hamming window signal to obtain a preprocessed reference signal.
Step 3, performing pulse compression on the preprocessed echo signals:
and an echo signal Fourier transform module in the pulse compression module performs Fourier transform on the preprocessed echo signal to obtain a frequency domain echo signal.
And a reference signal Fourier transform module in the pulse compression module performs Fourier transform on the preprocessed reference signal to obtain a frequency domain reference signal.
A conjugate multiplication module in the pulse compression module carries out conjugate processing on the frequency domain reference signal to obtain a conjugate frequency domain reference signal; multiplying the frequency domain echo signal by the conjugate frequency domain reference signal to obtain a pulse compression frequency domain signal;
and an inverse Fourier transform module in the pulse compression module performs inverse Fourier transform on the pulse compression frequency domain signal to obtain a pulse compression time domain signal.
Step 4, generating a Doppler frequency spectrum sequence:
and a pulse storage module in the moving target detection module sequentially splices pulse compression time domain signals continuously transmitted by the pulse compression radar for N times to obtain a signal sequence, wherein the value of N is a positive integer greater than 4.
The pulse storage module in the moving target detection module converts the signal sequence in sequence according to the line to obtain NxL 2 Matrix X of 1 Wherein L is 2 Representing the length of the pulse compressed time domain signal.
The parallel Fourier transform module in the moving target detection module converts the matrix X 1 Each column of (A) is Fourier transformed to obtain a matrix X 2 (ii) a Will matrix X 2 All elements in the matrix are subjected to modulus processing to obtain a matrix X 3 (ii) a Will matrix X 3 All elements in each row are added to form a Doppler spectrum sequence.
And 5, a speed calculation module in the moving target detection module finds out the element maximum value in the Doppler frequency spectrum sequence, and the Doppler frequency value corresponding to the maximum value is used as the speed of the moving target.
Step 6, performing moving target filtering on the pulse compression time domain signal:
and the moving target filtering module subtracts the pulse compression time domain signal between the previous adjacent transmissions from the pulse compression time domain signal between the current adjacent transmissions of the pulse compression radar to obtain a filtering signal for filtering the static target.
And 7, carrying out constant false alarm detection on the filtered signal by the constant false alarm module to obtain the position of the moving target.
Claims (3)
1. The utility model provides a pulse compression radar PCR echo signal processing system based on field programmable gate array FPGA, includes data acquisition module, pulse compression module, moves target filter module, moves target detection module, permanent false alarm module, its characterized in that: the system also comprises a signal preprocessing module, wherein all modules are developed in a graphical mode; wherein:
the data acquisition module is used for taking a pulse compression signal transmitted by the pulse compression radar for the first time as a reference signal, recording the time for finishing transmitting the reference signal as the pulse width of the reference signal, and taking the sampling frequency f as the echo signal of the pulse compression radar received in real time after the pulse compression radar transmits the pulse compression signal for the first time as the sampling frequency f s1 Sampling to obtain echo signal, wherein f s1 ＞500MHz；
The signal preprocessing module comprises: the device comprises a digital down-conversion module, a down-sampling module, an echo signal supplementing module, a Hamming window generating module, a Hamming window signal supplementing module, a reference signal preprocessing module and a Hamming window module; the digital down-conversion module is used for performing digital down-conversion processing on the echo signal to obtain a zero-intermediate-frequency complex signal; carrying out zero intermediate frequency complex signal
Multiple down-sampling to obtain the length of
Wherein denotes a multiplication operation, f s2 Indicating the frequency of sampling the zero intermediate frequency complex signal, and L indicating the length of the echo signal; echo signal supplementing module for supplementing tail of down-sampling echo signal
Zero-counting to obtain a preprocessed echo signal, wherein ceil represents an upward rounding operation, log 2 Denotes base 2 logarithmic operation, L 1 Representing the length of the down-sampled echo signal; a Hamming window generation module for generating a window having a width of
Wherein τ represents a pulse width of the reference signal; a Hamming window signal complementing module for complementing the tail of the Hamming window signal
Zero, obtaining a hamming window signal of a complete length, wherein L w Representing the length of a hamming window signal; a reference signal preprocessing module, configured to process the reference signal by using the same processing method as that used for processing the echo signal in this step, so as to obtain a reference signal with a length equal to the length of the echo signal;
the Hamming window module is used for multiplying the reference signal with the length compensated by the Hamming window signal to obtain a preprocessed reference signal;
the pulse compression module includes: the device comprises an echo signal Fourier transform module, a reference signal Fourier transform module, a conjugate multiplication module and an inverse Fourier transform module; the echo signal Fourier transform module is used for performing Fourier transform on the preprocessed echo signal to obtain a frequency domain echo signal; the reference signal Fourier transform module is used for carrying out Fourier transform on the preprocessed reference signal to obtain a frequency domain reference signal; the conjugate multiplication module is used for performing conjugate processing on the frequency domain reference signal to obtain a conjugate frequency domain reference signal; multiplying the frequency domain echo signal by the conjugate frequency domain reference signal to obtain a pulse compression frequency domain signal; the inverse Fourier transform module is used for performing inverse Fourier transform on the pulse compression frequency domain signal to obtain a pulse compression time domain signal;
the moving target filtering module is used for subtracting the pulse compression time domain signal between the previous adjacent transmissions from the pulse compression time domain signal between the current adjacent transmissions of the pulse compression radar to obtain a filtering signal for filtering the static target;
the moving target detection module comprises: the device comprises a pulse storage module, a pulse transformation module, a parallel Fourier transformation module and a speed calculation module; the pulse storage module is used for sequentially splicing pulse compression time domain signals continuously transmitted by the pulse compression radar for N times to obtain a signal sequence, wherein N isIs a positive integer greater than 4; a pulse conversion module for sequentially converting the signal sequence into NxL 2 Matrix X of 1 Wherein L is 2 Representing the length of the pulse compressed time domain signal; a parallel Fourier transform module for transforming the matrix X 1 Each column of (A) is Fourier transformed to obtain a matrix X 2 (ii) a Will matrix X 2 All elements in the matrix are subjected to modulus processing to obtain a matrix X 3 (ii) a Will matrix X 3 All elements in each row are added to form a Doppler frequency spectrum sequence; the velocity calculation module is used for finding out the element maximum value in the Doppler frequency spectrum sequence and taking the Doppler frequency value corresponding to the maximum value as the velocity of the moving target;
and the constant false alarm module is used for carrying out constant false alarm detection on the filtering signal to obtain the position of the moving target.
2. The pulse compression radar PCR echo signal processing system based on the field programmable gate array FPGA according to claim 1, wherein the echo signal is down-sampled and the down-sampled echo signal is filled up, and the method comprises the following steps:
step 1, receiving a pulse compression radar PCR echo signal in real time:
the data acquisition module takes a pulse compression signal transmitted by the pulse compression radar for the first time as a reference signal, the time for completing the transmission of the reference signal is recorded as the pulse width of the reference signal, and a pulse compression radar echo signal received in real time after the pulse compression radar transmits the pulse compression signal for the first time takes the sampling frequency as f s1 Sampling to obtain echo signals, wherein f s1 ＞500MHz；
Step 2, preprocessing the echo signal and the reference signal:
a digital down-conversion module in the signal preprocessing module performs digital down-conversion processing on the echo signal to obtain a zero intermediate frequency complex signal;
the down-sampling module in the signal preprocessing module carries out zero intermediate frequency complex signal
Multiple down-sampling to obtain the length of
Wherein denotes a multiplication operation, f s2 Indicating the frequency of sampling the zero intermediate frequency complex signal, and L indicating the length of the echo signal;
echo signal supplementing module in signal preprocessing module supplements echo signal at tail end of down-sampling echo signal
Zero, obtaining a preprocessed echo signal, wherein ceil represents an upward rounding operation, log 2 Denotes base 2 logarithmic operation, L 1 Representing the length of the down-sampled echo signal;
the Hamming window generation module in the signal preprocessing module generates a signal with a width of
Wherein τ represents a pulse width of the reference signal;
hamming window signal supplementing module in signal preprocessing module supplements at tail of Hamming window signal
Zero, obtaining a hamming window signal of a complete length, wherein L w Representing the length of the hamming window signal;
a reference signal preprocessing module in the signal preprocessing module processes the reference signal by adopting the same processing method as the method for processing the echo signal in the step to obtain a reference signal with the length being supplemented;
a Hamming window module in the signal preprocessing module multiplies the length-compensated reference signal by the length-compensated Hamming window signal to obtain a preprocessed reference signal;
step 3, performing pulse compression on the preprocessed echo signals:
an echo signal Fourier transform module in the pulse compression module performs Fourier transform on the preprocessed echo signal to obtain a frequency domain echo signal;
a reference signal Fourier transform module in the pulse compression module performs Fourier transform on the preprocessed reference signal to obtain a frequency domain reference signal;
a conjugate multiplication module in the pulse compression module carries out conjugate processing on the frequency domain reference signal to obtain a conjugate frequency domain reference signal; multiplying the frequency domain echo signal by the conjugate frequency domain reference signal to obtain a pulse compression frequency domain signal;
an inverse Fourier transform module in the pulse compression module performs inverse Fourier transform on the pulse compression frequency domain signal to obtain a pulse compression time domain signal;
step 4, generating a Doppler frequency spectrum sequence:
a pulse storage module in the moving target detection module sequentially splices pulse compression time domain signals continuously transmitted by a pulse compression radar for N times to obtain a signal sequence, wherein the value of N is a positive integer greater than 4;
the pulse storage module in the moving target detection module converts the signal sequence in sequence according to the line to obtain NxL 2 Matrix X of 1 Wherein, L 2 Representing the length of the pulse compressed time domain signal;
the parallel Fourier transform module in the moving target detection module converts the matrix X 1 Each column of (A) is Fourier transformed to obtain a matrix X 2 (ii) a Will matrix X 2 All elements in the matrix are subjected to modulus processing to obtain a matrix X 3 (ii) a Will matrix X 3 All elements in each row are added to form a Doppler frequency spectrum sequence;
step 5, a speed calculation module in the moving target detection module finds out the element maximum value in the Doppler frequency spectrum sequence, and the Doppler frequency value corresponding to the maximum value is taken as the speed of the moving target;
step 6, performing moving target filtering on the pulse compression time domain signal:
the moving target filtering module subtracts the pulse compression time domain signal between the previous adjacent transmissions from the pulse compression time domain signal between the current adjacent transmissions of the pulse compression radar to obtain a filtering signal for filtering the static target;
and 7, performing constant false alarm detection on the filtered signal by the constant false alarm module to obtain the position of the moving target.
3. The method for processing the PCR echo signal of the pulse compression radar based on the FPGA of the field programmable gate array according to claim 2, wherein the step 2 is performed by the zero intermediate frequency complex signal
The multiple down-sampling process is implemented according to the following formula:
wherein y (n) represents the nth element in the echo signal after down sampling, and the value range of n is 0 to L 1 -1, x (m) represents the m-th element in the complex signal at zero intermediate frequency.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1531968A (en) * | 1977-03-31 | 1978-11-15 | Raytheon Co | Pulse compression radar and method of operating such rada |
| CN1567271A (en) * | 2003-06-19 | 2005-01-19 | 欧阳捷 | Conversion and acquisition method and apparatus of MPEG code with highspeed network interface |
| CA2540936A1 (en) * | 2005-03-24 | 2006-09-24 | Hamid Shokrollah Timorabadi | A method and system for wide-range synchronization to alternating current power signals |
| CN109375206A (en) * | 2018-09-19 | 2019-02-22 | 北京遥感设备研究所 | A kind of moving target speed-measuring method based on speed search |
-
2020
- 2020-01-15 CN CN202010040051.2A patent/CN111198355B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1531968A (en) * | 1977-03-31 | 1978-11-15 | Raytheon Co | Pulse compression radar and method of operating such rada |
| CN1567271A (en) * | 2003-06-19 | 2005-01-19 | 欧阳捷 | Conversion and acquisition method and apparatus of MPEG code with highspeed network interface |
| CA2540936A1 (en) * | 2005-03-24 | 2006-09-24 | Hamid Shokrollah Timorabadi | A method and system for wide-range synchronization to alternating current power signals |
| CN109375206A (en) * | 2018-09-19 | 2019-02-22 | 北京遥感设备研究所 | A kind of moving target speed-measuring method based on speed search |
Non-Patent Citations (3)
| Title |
|---|
| 无源雷达多普勒谱分析实现动目标检测的方法;赵耀东等;《雷达学报》;20130615(第02期);全文 * |
| 无线电引信频域恒虚警率目标检测算法;石润龙等;《探测与控制学报》;20100226(第01期);全文 * |
| 脉冲多普勒雷达回波信号数据压缩处理方法;谢少波;《上海航天》;20050825(第04期);全文 * |
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