阅读说明：本技术 基于p/d波段雷达信号融合处理的高速目标检测方法 (High-speed target detection method based on P/D band radar signal fusion processing ) 是由 张仁李 张志嘉 盛卫星 马晓峰 韩玉兵 于 2019-11-08 设计创作，主要内容包括：本发明公开了一种基于P/D波段雷达信号融合处理的高速目标检测方法,包括以下步骤：选取P波段工作雷达的发射波形形式为伪随机二进制相移键控脉冲信号,D波段工作雷达的发射波形形式为线性调频连续波信号；确定P波段雷达的伪随机二进制相移键控脉冲发射波形参数和D波段雷达的线性调频连续波发射波形参数；对P波段和D波段对应的工作波形进行协同发射和接收；对P波段和D波段雷达的发射信号回波进行处理,将两种波形的信号处理结果进行融合处理,得到目标的距离和速度信息。本发明解决了高速运动目标在D波段雷达下易发生测速模糊的问题,提高了目标测距与测速的精度。(The invention discloses a high-speed target detection method based on P/D band radar signal fusion processing, which comprises the following steps: selecting a transmitting waveform form of a P-band working radar as a pseudo-random binary phase shift keying pulse signal, and selecting a transmitting waveform form of a D-band working radar as a linear frequency modulation continuous wave signal; determining a pseudorandom binary phase shift keying pulse transmission waveform parameter of a P-band radar and a linear frequency modulation continuous wave transmission waveform parameter of a D-band radar; carrying out cooperative transmission and reception on working waveforms corresponding to the P wave band and the D wave band; and processing echoes of transmitting signals of the P-band radar and the D-band radar, and fusing the signal processing results of the two waveforms to obtain distance and speed information of the target. The invention solves the problem that the high-speed moving target is easy to generate speed measurement blur under the D-band radar, and improves the precision of target distance measurement and speed measurement.)

1. A high-speed target detection method based on P/D band radar signal fusion processing is characterized by comprising the following steps:

step 1, selecting a transmitting waveform form of a P-band radar as a pseudo-random binary phase shift keying pulse signal, and selecting a transmitting waveform form of a D-band radar as a linear frequency modulation continuous wave waveform;

step 2, determining the transmitting waveform parameters of the P-band radar including code element width, pulse width and pulse repetition period according to the maximum distance measuring range, the maximum speed measuring range and the distance measuring precision; determining emission waveform parameters of the D-band radar, including sweep frequency bandwidth and sweep frequency period;

step 3, performing cooperative transmission and reception on working waveforms corresponding to the P-band radar and the D-band radar;

step 4, processing the BPSK transmitting signal echo of the P-band radar: the method comprises the steps that a digital signal is obtained after AD sampling and digital down-conversion are carried out on an echo of a transmitted signal, correlation processing is carried out on digital signal data obtained through sampling, a result is stored in a memory RAM, after N pulses are continuously transmitted to complete correlation processing, moving target detection processing is carried out on the same distance unit result in the N pulse correlation processing results to obtain a distance-Doppler two-dimensional plane, constant false alarm detection is carried out to obtain a target peak point, and distance and speed information of a target under a BPSK working waveform of a P waveband are obtained;

step 5, processing the LFMCW transmitting signal echo of the D-band radar: carrying out frequency mixing on a transmitting signal echo and a local oscillator signal to obtain a beat signal, carrying out windowing fast Fourier transform processing on beat signal data obtained by sampling to obtain a first-dimension FFT result, carrying out second-dimension FFT after one coherent accumulation time, namely N pulse repetition periods, forming a distance-Doppler two-dimensional plane after MTD is finished, carrying out CFAR detection processing on the MTD processing result to obtain the distance and Doppler information of a target point trace, and obtaining the distance and speed information of a target under a D waveband LFMCW working waveform;

and 6, fusing the processing results of the radar echo signals of the P wave band and the D wave band: matching the detection results of the P wave band and the D wave band in a distance dimension to obtain the distance and speed measurement results of the same target in two working modes; and for the same target, judging the fuzzy multiple of the target in the D wave band Doppler frequency measurement by using the P wave band speed measurement result, and performing fuzzy resolving treatment to obtain the target distance and speed information.

2. The high-speed target detection method based on P/D band radar signal fusion processing as claimed in claim 1, wherein step 2 determines BPSK emission waveform parameters of a P band radar, and determines BPSK emission waveform parameters according to a maximum ranging range, a maximum speed measurement range and ranging accuracy, wherein the BPSK emission waveform parameters include a symbol width, a pulse width and a pulse repetition period; determining LFMCW transmitted waveform parameters of a D-band radar, and determining the LFMCW transmitted waveform parameters according to the maximum ranging range and the ranging precision, wherein the LFMCW transmitted waveform parameters comprise a sweep frequency bandwidth and a sweep frequency period, and the method specifically comprises the following steps:

firstly, setting BPSK emission waveform parameters of a P-band radar as follows: pulse width t of waveform_h,PPulse repetition period T_r,PSymbol width τ_P；

The code element width is set to match with the antenna bandwidth, and the 3dB bandwidth corresponding to the transmitted signal is 1/tau_P；

Pulse repetition period T_r,PCorresponding to the maximum operating distance R of the radar_max：

Wherein c is the speed of light;

the bandwidth of the emission waveform is 1/tau_PThe corresponding radar range resolution is:

the maximum relative movement speed of the target is v_maxCorresponding to the longest accumulation time:

setting a coherent processing interval T_CPI,PThe maximum accumulation time cannot be exceeded, corresponding to a doppler resolution of:

corresponding velocity resolution:

wherein f is₀Is the carrier frequency;

the parameters of the emission waveform of the D-band radar LFMCW are set as follows: swept bandwidth of waveform B_DSweep period T of waveform_r,D；

In the sweep frequency section of LFMCW emission wave, the sweep frequency bandwidth is determined according to the ranging resolution and the ranging precision delta R required by the system, namely

Waveform sweep period T_r,DCorresponding to the maximum operating distance R of the radar_max：

3. The high-speed target detection method based on P/D band radar signal fusion processing as claimed in claim 1, wherein step 3 is to perform cooperative transmission and reception of working waveforms corresponding to the P-band and D-band radars: the two working waveforms are simultaneously transmitted within corresponding coherent accumulation time, the P-band radar receives a target echo after the transmission pulse is finished, and the D-band radar samples and processes the target beat echo in the effective receiving period of the LFMCW transmission signal frequency sweep period.

4. The method for detecting a high-speed target based on P/D band radar signal fusion processing according to claim 1, wherein the correlation processing is performed on the BPSK transmission signal echo of the P band radar in step 4, specifically as follows:

obtaining a digital baseband signal after AD sampling and digital down-conversion of the BPSK echo signal, wherein the digital baseband signal is an amplitude modulation signal of which the transmitting code word is delayed and modulated to Doppler frequency, the target echo signal is changed into a digital signal, then the digital baseband signal is sent to each range gate to be multiplied and accumulated with a reference code, and the maximum output is obtained on the range gate matched with the code word; the reference code on each range gate is obtained by delaying a code word by one code element time in sequence; each range gate differs in turn by one symbol time, so the range resolution is c τ_P2; thus, through one-time correlation accumulation processing, a group of data with the length of P is compressed into one data to complete one-time accumulation, so that the correlation accumulation is also called pulse compression;

then compressing the next group of data with the length of P, repeating the steps in sequence, and sending the related processing result to a memory RAM until all the data are processed;

finally, FFT is carried out on the data after pulse pressure according to a range gate to obtain a range-Doppler two-dimensional plane, and then CFAR processing is carried out to obtain range and speed information of the target under the BPSK waveform of the P wave band;

to correlationThe device outputs data Y under the same distance gate_r(1: N, m) is processed by N-point FFT to obtain corresponding Doppler dimensional data F_r(n, m), namely:

F_r(1:N,m)＝fft[Y_r(1:N,m)](8)

wherein F_r(n, m) represents the result of the nth doppler cell of the mth range cell after the echo is processed by the MTD.

5. The method for detecting a high-speed target based on the fusion processing of the signals of the P/D band radar according to claim 1, wherein the step 5 is to process the LFMCW transmission signal echo of the D band radar, and specifically comprises the following steps:

carrying out frequency mixing on LFMCW transmitting signal echoes and local oscillator signals to obtain beat signals, and carrying out AD sampling on the echo beat signals;

the maximum distance of the target is R_maxThe maximum corresponding echo delay is:

for τ after one sweep period_max～T_rSampling echo beat signals in the period, performing first-dimension FFT (fast Fourier transform) conversion, respectively storing the signals into corresponding memories RAM (random access memory) according to range gates, performing second-dimension FFT conversion on the data stored in each range gate after a coherent processing interval CPI (common instruction symbol), namely forming a range-Doppler two-dimensional plane after MTD (maximum transmission rate) processing, and performing CFAR (constant frequency Radar) detection processing on an MTD processing result to obtain the range and Doppler information of a target in a D-band LFMCW (linear frequency modulation and continuous phase modulation) working waveform;

the target beat frequency measured by the first dimension FFT processing is:

wherein R is the target distance, f_dIs the target doppler frequency.

The target fuzzy Doppler frequency measured by MTD processing is recorded as f_d,DThe target distance is obtained by substituting the formula:

wherein μ ═ B_D/T_r,DAnd mu is the chirp rate of the D-band LFMCW waveform.

6. The method for detecting a high-speed target based on the fusion processing of the radar signals in the P/D band according to claim 1, wherein the fusion processing of the processing results of the radar echo signals in the P band and the D band in step 6 is specifically as follows:

matching the detection results of the P wave band and the D wave band on a distance dimension to obtain distance and speed measurement results of the same target in two working modes;

using the P-band velocity measurement v for the same target_PJudging the Doppler frequency measurement fuzzy multiple N of the target under the D-band radar_DAs shown in the following formula:

wherein v is_max,DMaximum unambiguous detection speed, λ, of the LFMCW waveform in the D band_DIs the wavelength of the D band LFMCW waveform;

according to the obtained D-band Doppler frequency fuzzy multiple, carrying out deblurring processing to obtain the non-fuzzy Doppler frequency f of the target under the D-band_d：

f_d＝f_d,D+N_D/T_r,D(14)

Wherein T is_r,DThe sweep period of the LFMCW waveform of the D wave band is obtained, and the target accurate speed is obtained by the following steps:

the D wave band LFMCW target beat frequency f_BAnd a non-ambiguous Doppler frequency f_dIn combination, the precise distance to the target is obtained as:

wherein μ ═ B_D/T_r,DAnd mu is the chirp rate of the D-band LFMCW waveform.

Technical Field

The invention belongs to the technical field of radar information, and particularly relates to a high-speed target detection method based on P/D band radar signal fusion processing.

Background

The rapid development of stealth technology in recent years poses serious challenges to strategic and tactical defense systems, forcing people to consider how to destroy stealth weapons and study anti-stealth technology. The frequency band with the best effect of the stealth aircraft in active service is 1-40 GHz, and if the radar working frequency exceeds the range, the radar detection capability can be obviously improved, so that the stealth capability of the stealth aircraft is greatly reduced.

The P-band frequency range is 0.23-1 GHz, the D-band frequency range is 110-170 GHz, and the P-band frequency range and the D-band frequency range are both outside the stealth frequency band, so that the P-band radar and the D-band radar have excellent anti-stealth capability. The P-band uses Binary Phase Shift Keying (BPSK) working waveform, the D-band uses Linear Frequency Modulated Continuous Wave (LFMCW) working waveform, both have higher ranging accuracy, but in the aspect of speed measurement performance, the wavelength of a P-band radar transmission signal is large, so that the problem of poor speed measurement accuracy exists. The D-band LFMCW radar has high speed measurement accuracy, but the working waveform wavelength is small, so that the speed measurement fuzzy phenomenon caused by Doppler fuzzy is easily caused.

Disclosure of Invention

The invention aims to provide a high-speed target detection method based on P/D band radar signal fusion processing, so as to improve the target distance and speed measurement accuracy and achieve the anti-stealth effect.

The technical solution for realizing the purpose of the invention is as follows: a high-speed target detection method based on P/D band radar signal fusion processing comprises the following steps:

step 1, selecting a transmitting waveform form of a P-band radar as a pseudo-random binary phase shift keying pulse signal, and selecting a transmitting waveform form of a D-band radar as a linear frequency modulation continuous wave waveform;

step 2, determining the transmitting waveform parameters of the P-band radar including code element width, pulse width and pulse repetition period according to the maximum distance measuring range, the maximum speed measuring range and the distance measuring precision; determining emission waveform parameters of the D-band radar, including sweep frequency bandwidth and sweep frequency period;

step 3, performing cooperative transmission and reception on working waveforms corresponding to the P-band radar and the D-band radar;

step 4, processing the BPSK transmitting signal echo of the P-band radar: the method comprises the steps that a digital signal is obtained after AD sampling and digital down-conversion are carried out on an echo of a transmitted signal, correlation processing is carried out on digital signal data obtained through sampling, a result is stored in a memory RAM, after N pulses are continuously transmitted to complete correlation processing, moving target detection processing is carried out on the same distance unit result in the N pulse correlation processing results to obtain a distance-Doppler two-dimensional plane, constant false alarm detection is carried out to obtain a target peak point, and distance and speed information of a target under a BPSK working waveform of a P waveband are obtained;

step 5, processing the LFMCW transmitting signal echo of the D-band radar: carrying out frequency mixing on a transmitting signal echo and a local oscillator signal to obtain a beat signal, carrying out windowing fast Fourier transform processing on beat signal data obtained by sampling to obtain a first-dimension FFT result, carrying out second-dimension FFT after one coherent accumulation time, namely N pulse repetition periods, forming a distance-Doppler two-dimensional plane after MTD is finished, carrying out CFAR detection processing on the MTD processing result to obtain the distance and Doppler information of a target point trace, and obtaining the distance and speed information of a target under a D waveband LFMCW working waveform;

and 6, fusing the processing results of the radar echo signals of the P wave band and the D wave band: matching the detection results of the P wave band and the D wave band in a distance dimension to obtain the distance and speed measurement results of the same target in two working modes; and for the same target, judging the fuzzy multiple of the target in the D wave band Doppler frequency measurement by using the P wave band speed measurement result, and performing fuzzy resolving treatment to obtain the target distance and speed information.

Further, determining BPSK transmitting waveform parameters of the P-band radar in step 2, and determining the BPSK transmitting waveform parameters according to the maximum ranging range, the maximum speed measuring range and the ranging precision, wherein the BPSK transmitting waveform parameters comprise code element width, pulse width and pulse repetition period; determining LFMCW transmitted waveform parameters of a D-band radar, and determining the LFMCW transmitted waveform parameters according to the maximum ranging range and the ranging precision, wherein the LFMCW transmitted waveform parameters comprise a sweep frequency bandwidth and a sweep frequency period, and the method specifically comprises the following steps:

firstly, setting BPSK emission waveform parameters of a P-band radar as follows: pulse width t of waveform_h,PPulse repetition period T_r,PSymbol width τ_P；

The code element width is set to match with the antenna bandwidth, and the 3dB bandwidth corresponding to the transmitted signal is 1/tau_P；

Pulse repetition period T_r,PCorresponding to the maximum operating distance R of the radar_max：

Wherein c is the speed of light;

the bandwidth of the emission waveform is 1/tau_PThe corresponding radar range resolution is:

the maximum relative movement speed of the target is v_maxCorresponding to the longest accumulation time:

setting a coherent processing interval T_CPI,PThe maximum accumulation time cannot be exceeded, corresponding to a doppler resolution of:

corresponding velocity resolution:

wherein f is₀To be loadedA wave frequency;

the parameters of the emission waveform of the D-band radar LFMCW are set as follows: swept bandwidth of waveform B_DSweep period T of waveform_r,D；

In the sweep frequency section of LFMCW emission wave, the sweep frequency bandwidth is determined according to the ranging resolution and the ranging precision delta R required by the system, namely

Waveform sweep period T_r,DCorresponding to the maximum operating distance R of the radar_max：

Further, step 3 is to perform cooperative transmission and reception on the working waveforms corresponding to the P-band radar and the D-band radar: the two working waveforms are simultaneously transmitted within corresponding coherent accumulation time, the P-band radar receives a target echo after the transmission pulse is finished, and the D-band radar samples and processes the target beat echo in the effective receiving period of the LFMCW transmission signal frequency sweep period.

Further, the step 4 of performing correlation processing on the BPSK transmission signal echo of the P-band radar specifically includes:

obtaining a digital baseband signal after AD sampling and digital down-conversion of the BPSK echo signal, wherein the digital baseband signal is an amplitude modulation signal of which the transmitting code word is delayed and modulated to Doppler frequency, the target echo signal is changed into a digital signal, then the digital baseband signal is sent to each range gate to be multiplied and accumulated with a reference code, and the maximum output is obtained on the range gate matched with the code word; the reference code on each range gate is obtained by delaying a code word by one code element time in sequence; each range gate differs in turn by one symbol time, so the range resolution is c τ _P2; thus, through one-time correlation accumulation processing, a group of data with the length of P is compressed into one data to complete one-time accumulation, so that the correlation accumulation is also called pulse compression;

then compressing the next group of data with the length of P, repeating the steps in sequence, and sending the related processing result to a memory RAM until all the data are processed;

finally, FFT is carried out on the data after pulse pressure according to a range gate to obtain a range-Doppler two-dimensional plane, and then CFAR processing is carried out to obtain range and speed information of the target under the BPSK waveform of the P wave band;

outputting data Y under the same range gate to the correlator_r(1: N, m) is processed by N-point FFT to obtain corresponding Doppler dimensional data F_r(n, m), namely:

F_r(1:N,m)＝fft[Y_r(1:N,m)](8)

wherein F_r(n, m) represents the result of the nth doppler cell of the mth range cell after the echo is processed by the MTD.

Further, the processing of the LFMCW transmission signal echo of the D-band radar in step 5 is specifically as follows:

carrying out frequency mixing on LFMCW transmitting signal echoes and local oscillator signals to obtain beat signals, and carrying out AD sampling on the echo beat signals;

the maximum distance of the target is R_maxThe maximum corresponding echo delay is:

for τ after one sweep period_max～T_rSampling echo beat signals in the period, performing first-dimension FFT (fast Fourier transform) conversion, respectively storing the signals into corresponding memories RAM (random access memory) according to range gates, performing second-dimension FFT conversion on the data stored in each range gate after a coherent processing interval CPI (common instruction symbol), namely forming a range-Doppler two-dimensional plane after MTD (maximum transmission rate) processing, and performing CFAR (constant frequency Radar) detection processing on an MTD processing result to obtain the range and Doppler information of a target in a D-band LFMCW (linear frequency modulation and continuous phase modulation) working waveform;

the target beat frequency measured by the first dimension FFT processing is:

wherein R is the target distance, f_dIs the target doppler frequency.

The target fuzzy Doppler frequency measured by MTD processing is recorded as f_d,DThe target distance is obtained by substituting the formula:

wherein μ ═ B_D/T_r,DAnd mu is the chirp rate of the D-band LFMCW waveform.

Further, in step 6, the processing results of the radar echo signals in the P-band and the D-band are fused, specifically as follows:

matching the detection results of the P wave band and the D wave band on a distance dimension to obtain distance and speed measurement results of the same target in two working modes;

using the P-band velocity measurement v for the same target_PJudging the Doppler frequency measurement fuzzy multiple N of the target under the D-band radar_DAs shown in the following formula:

wherein v is_max,DMaximum unambiguous detection speed, λ, of the LFMCW waveform in the D band_DIs the wavelength of the D band LFMCW waveform;

according to the obtained D-band Doppler frequency fuzzy multiple, carrying out deblurring processing to obtain the non-fuzzy Doppler frequency f of the target under the D-band_d：

f_d＝f_d,D+N_D/T_r,D(14)

Wherein T is_r,DThe sweep period of the LFMCW waveform of the D wave band is obtained, and the target accurate speed is obtained by the following steps:

the D wave band LFMCW target beat frequency f_BAnd a non-ambiguous Doppler frequency f_dIn combination, the precise distance to the target is obtained as:

wherein μ ═ B_D/T_r,DAnd mu is the chirp rate of the D-band LFMCW waveform.

Compared with the prior art, the invention has the following remarkable advantages: (1) the radar working waveform is outside the working frequency band of the stealth coating, so that the aim of frequency domain anti-stealth can be fulfilled; (2) the problem that speed measurement ambiguity easily occurs to a high-speed target in a D-band LFMCW working mode is solved, and the phenomenon that the compression effect of a P-band phase coding signal on a radar receiver is reduced by Doppler frequency shift of a high-speed target echo is solved; (3) the target pairing mode is simple, the operation amount is low, the distance measurement and speed measurement accuracy is high, the principle is simple, good real-time performance can be achieved even if low-cost devices are used, and the performance and the cost are competitive.

Drawings

FIG. 1 is a flow chart of a high-speed target detection method based on P/D band radar signal fusion processing.

Fig. 2 is a schematic diagram of the cooperative transmission of P-band and D-band operating waveforms in accordance with the present invention.

FIG. 3 is a schematic diagram of the P-band echo signal correlation process of the present invention.

FIG. 4 is a flow chart of the P-band echo signal processing of the present invention.

Fig. 5 is a flow chart of the D-band LFMCW echo signal processing of the present invention.

FIG. 6 is a flow chart of the fusion process of the P-band and D-band radar signals of the present invention.

Fig. 7 is a detection precision comparison diagram of P-band signal processing, D-band signal processing, and P-band and D-band radar signal fusion processing according to the present invention, where fig. 7(a) is a distance measurement error comparison diagram, and fig. 7(b) is a speed measurement error comparison diagram.

Detailed Description

The invention provides a high-speed target detection method based on P/D band radar signal fusion processing, which mainly comprises three parts of P/D band waveform structure design, waveform parameter design and signal processing design, as shown in figure 1, the method comprises the following specific steps:

the method comprises the following steps: designing a P/D wave band emission waveform form: selecting a transmitting waveform form of a P-band radar as a pseudo random Phase Shift Keying (BPSK) pulse signal, and selecting a transmitting waveform form of a D-band radar as a Linear Frequency Modulated Continuous Wave (LFMCW) waveform;

step two: designing the transmitting waveform parameters of the P/D band radar: determining the transmitted waveform parameters of the P-band radar, and determining the waveform parameters according to the maximum ranging range, the maximum speed measuring range and the ranging precision, wherein the waveform parameters comprise code element width, pulse width and pulse repetition period; determining transmitted waveform parameters of a D-band radar, and determining the waveform parameters according to the maximum ranging range and the ranging precision, wherein the waveform parameters comprise sweep frequency bandwidth and sweep frequency period; the parameter setting of the transmitted waveform of the P/D band radar ensures that the range ambiguity does not occur in the maximum range, so as to facilitate the target matching in the fusion processing process.

Firstly, setting BPSK emission waveform parameters of a P-band radar as follows: pulse width t of waveform_h,PPulse repetition period T_r,PSymbol width τ_P；

The code element width is set to match with the antenna bandwidth, and the 3dB bandwidth corresponding to the transmitted signal is 1/tau_P；

Pulse repetition period T_r,PCorresponding to the maximum operating distance R of the radar_max：

Wherein c is the speed of light;

the bandwidth of the emission waveform is 1/tau_PThe corresponding radar range resolution is:

the maximum relative movement speed of the target is v_maxCorresponding to the longest accumulation time:

setting a coherent processing interval T_CPI,PThe maximum accumulation time cannot be exceeded, corresponding to a doppler resolution of:

corresponding velocity resolution:

where c is the speed of light, f₀Is the carrier frequency;

the parameters of the emission waveform of the D-band radar LFMCW are set as follows: swept bandwidth of waveform B_DSweep period T of waveform_r,D；

In the sweep frequency section of LFMCW emission wave, the sweep frequency bandwidth is determined according to the ranging resolution and the ranging precision delta R required by the system, namely

Wherein c is the speed of light;

waveform sweep period T_r,DCorresponding to the maximum operating distance R of the radar_max：

Wherein c is the speed of light;

the working waveforms corresponding to the P-band radar and the D-band radar are transmitted and received cooperatively, as shown in fig. 2, the two working waveforms are transmitted simultaneously within corresponding coherent accumulation time, the P-band radar receives a target echo after the transmission pulse is finished, and the D-band radar performs sampling and processing of a target beat echo in the effective receiving period of the LFMCW transmission signal frequency sweep period.

Step three: designing a P/D waveband signal processing mode: as shown in fig. 3 and 4, the BPSK transmit signal echo of the P-band radar is correlated: the BPSK echo signals are subjected to AD sampling and digital down-conversion to obtain digital baseband signals, the digital baseband signals are amplitude modulation signals of transmitting code words on Doppler frequency through delay modulation, target echo signals are changed into digital signals, then the digital baseband signals are sent into each range gate to be multiplied and accumulated with reference codes, and the maximum output can be obtained on the range gates matched with the code words. The reference code at each range gate is obtained by transmitting a code word with a delay of one symbol time in turn. Each range gate differs in turn by one symbol time, so the range resolution is c τ_P/2. Thus, a group of data with the length of P can be compressed into one data through one correlation accumulation process, and one accumulation is completed, so that the correlation accumulation is also called as pulse compression. And then compressing the next group of data with the length of P, repeating the steps in sequence, and sending the related processing result to a memory RAM until all the data are processed. And finally, performing FFT on the data after pulse pressure according to a range gate to obtain a range-Doppler two-dimensional plane, and then performing Constant False Alarm Rate (CFAR) detection to obtain range and speed information of the target under the BPSK waveform of the P waveband.

Outputting data Y under the same range gate to the correlator_r(1: N, m) is processed by N-point FFT to obtain corresponding Doppler dimensional data F_r(n, m), namely:

F_r(1:N,m)＝fft[Y_r(1:N,m)](8)

wherein F_r(n, m) represents the result of the nth doppler cell of the mth range cell after the echo is processed by Moving Target Detection (MTD).

The LFMCW transmitting signal echo of the D-band radar is processed, as shown in fig. 5:

and performing frequency mixing on the LFMCW transmitting signal echo and the local oscillator signal to obtain a beat signal, and performing AD sampling on the echo beat signal.

The maximum distance of the target is R_maxThe maximum corresponding echo delay is:

to make the echo beat signal continuous during the sampling period, for a sweep period, τ_max～T_rAnd sampling echo beat signals in the period, performing first-dimension FFT (fast Fourier transform) conversion, respectively storing the signals into corresponding memories RAM (random access memory) according to range gates, performing second-dimension FFT conversion on the data stored in each range gate after a coherent processing interval CPI (common reference symbol), namely forming a range-Doppler two-dimensional plane after MTD (maximum transmission rate) processing, and performing CFAR (constant false alarm rate) detection processing on an MTD processing result to obtain the range and Doppler information of a target in a D-band LFMCW (linear frequency modulation and continuous phase modulation) working waveform.

The target beat frequency measured by the first dimension FFT processing is:

wherein R is the target distance, f_dIs the target doppler frequency.

The target fuzzy Doppler frequency measured by MTD processing is recorded as f_d,DThe target distance is obtained by substituting the formula:

wherein μ ═ B_D/T_r,DAnd mu is the chirp rate of the D-band LFMCW waveform.

As shown in fig. 6, the fusion processing of the processing results of the echo signals of the P-band radar and the D-band radar is specifically as follows:

step 1: matching the detection results of the P wave band and the D wave band on a distance dimension to obtain distance and speed measurement results of the same target in two working modes;

step 2: for the same object, the P-band is usedVelocity measurement v_PJudging the Doppler frequency measurement fuzzy multiple N in the D wave band_DAs shown in the following formula:

wherein v is_max,DMaximum unambiguous detection speed, λ, of the LFMCW waveform in the D band_DIs the wavelength of the D band LFMCW waveform;

and 3, step 3: according to the obtained D-band Doppler frequency fuzzy multiple, carrying out deblurring processing to obtain D-band non-fuzzy Doppler frequency f_d：

f_d＝f_d,D+N_D/T_r,D(14)

Wherein T is_r,DThe sweep period of the LFMCW waveform of the D wave band is obtained, and the target accurate speed is obtained by the following steps:

wherein λ_DThe wavelength of the working waveform of the D-band radar LFMCW.

And 4, step 4: combining the beat frequency of the D-band LFMCW target with the unambiguous Doppler frequency to obtain the accurate distance of the target:

wherein μ ═ B_D/T_r,DAnd mu is the chirp rate of the D-band LFMCW waveform.

The present invention will be described in detail with reference to examples.