WO2024061206A1 - 一种线性调频脉冲雷达的目标探测方法 - Google Patents

一种线性调频脉冲雷达的目标探测方法 Download PDF

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WO2024061206A1
WO2024061206A1 PCT/CN2023/119673 CN2023119673W WO2024061206A1 WO 2024061206 A1 WO2024061206 A1 WO 2024061206A1 CN 2023119673 W CN2023119673 W CN 2023119673W WO 2024061206 A1 WO2024061206 A1 WO 2024061206A1
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frequency
signal
target
difference
radar
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PCT/CN2023/119673
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English (en)
French (fr)
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严济鸿
翟鉴枢
倪伟涵
张欢
杨礼
董海洋
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电子科技大学长三角研究院(衢州)
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Publication of WO2024061206A1 publication Critical patent/WO2024061206A1/zh

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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
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • 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
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/50—Systems of measurement based on relative movement of target
    • G01S13/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
    • 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
    • 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
    • G01S7/415—Identification of targets based on measurements of movement associated with the target

Definitions

  • the present invention relates to the field of radar, in particular to linear frequency modulation radar, and specifically to a target detection method of linear frequency modulation pulse radar.
  • Linear frequency modulation radar can use the difference frequency between the echo signal and the transmitted signal to measure the target distance, but the difference frequency will also be affected by the speed of the moving target, so the range Doppler coupling phenomenon will occur.
  • the traditional method requires two-dimensional Fourier transform processing on the echo signal at this time.
  • the signal processing algorithm has a complex structure and high algorithm complexity.
  • the present invention aims to provide a target detection method of a linear frequency modulation pulse radar.
  • the present invention solves the problems of complex signal processing algorithm structure and high algorithm complexity in traditional methods, and simplifies the algorithm process.
  • the present invention mixes the LFM radar multiple-period received signals and the transmitted waveform, and then samples all the mixed signals and performs Fourier transform.
  • the radar system of the present invention after the target echo is mixed with the original linear frequency modulation continuous wave, it only needs to perform a one-dimensional fast Fourier transform (FFT) to measure the speed and distance information of the target.
  • FFT fast Fourier transform
  • the present invention provides a target detection method for linear frequency modulated pulse radar, which is characterized in that it includes:
  • the radar emission signal and the target echo signal are mixed, filtered, and sampled in sequence, and then a fast Fourier transform is performed to obtain the signal spectrum;
  • the estimated difference frequency of the target echo signal and the radar transmission signal is obtained;
  • Target distance information is calculated through the estimated difference frequency and the delayed difference frequency.
  • the present invention provides a target detection method of a linear frequency modulation pulse radar, comprising:
  • the frequency corresponding to the peak value in the signal spectrum and the harmonic frequency of its nearest transmitted signal pulse repetition frequency are used to obtain the Doppler frequency caused by the target movement and calculate the target speed;
  • the difference frequency caused by the target echo range delay is obtained through the difference frequency and the Doppler frequency, and the target distance information is calculated.
  • the radar transmission signal is a linear frequency modulated pulse signal generated by a signal generator.
  • obtaining the Doppler frequency through the signal spectrum and calculating the target speed includes:
  • the Doppler frequency caused by the target movement is obtained based on the frequency corresponding to the peak value in the signal spectrum and the harmonic frequency of the transmit signal pulse repetition frequency closest to the peak value.
  • the Doppler frequency is the frequency corresponding to the peak value and the frequency of the pulse.
  • the target distance information is calculated, including :
  • the difference frequency between the target echo signal and the estimated radar transmission signal is obtained through spectrum correction, and then the difference frequency caused by the echo distance delay is obtained through the Doppler frequency.
  • the difference frequency caused by the echo distance delay is the echo The difference between the estimated difference frequency of the signal and the transmitted signal and the Doppler frequency.
  • the invention provides a linear frequency modulation pulse radar target detection method, the specific steps are as follows:
  • Step 1 Use a linear frequency modulation pulse signal generator to generate a linear frequency modulation pulse signal with a bandwidth of B, a radio frequency frequency of f G , an FM slope of ⁇ , a pulse repetition frequency of f PRF , and a duty cycle of 50%;
  • Step 2 Receive the multi-period target echo signal through the receiving antenna, and compare the echo signal with step 1 The generated linear frequency modulation pulse signal is mixed;
  • Step 3 The mixed signal is passed through a low-pass filter to obtain a difference frequency signal, and the difference frequency signal is sampled by ADC to obtain a sampling signal, and the sampling frequency is fs;
  • Step 4 The digital signal processor performs FFT processing on the sampled signal to obtain the spectrum
  • Step 5 Extract the Doppler frequency and the difference frequency between the echo signal and the transmitted signal from the spectrum obtained in step 4, and select the frequency corresponding to the maximum value of the target echo signal after processing and the pulse repetition frequency closest to the frequency corresponding to the maximum value.
  • the difference in harmonic frequency is the Doppler frequency f d caused by the target's movement speed.
  • Step 6 Obtain the target speed v and target distance information R through f ⁇ and f d in step 5.
  • the present invention provides a target detection device for linear frequency modulation pulse radar, including:
  • Chirp signal generator for transmitting radar transmission signals to targets
  • Filter used to filter the signal after mixing the target emission signal and the echo signal
  • ADC used to sample the mixed and filtered signal
  • the fast Fourier module is used to perform a fast Fourier transform on the filtered signal to obtain the signal spectrum
  • the calculation module is used to obtain the target distance and speed from the spectrum, specifically including: obtaining the Doppler frequency caused by the target movement through the frequency corresponding to the peak value in the signal spectrum and the harmonic frequency of its nearest transmit signal pulse repetition frequency. , calculate the target speed; estimate the difference frequency of the radar transmission signal and the target echo signal; obtain the difference frequency caused by the target echo distance delay through the difference frequency and the Doppler frequency, and calculate the target distance. information.
  • an electronic device includes: a processor, and a memory communicatively connected to the processor;
  • the memory stores computer execution instructions
  • the processor executes computer execution instructions stored in the memory to implement the method according to any one of the first aspects.
  • a fifth aspect a computer program product, comprising a computer program, the computer program being processed When executed by a device or chip, the method as described in any one of the first aspects is implemented.
  • the present invention provides a computer-readable storage medium in which computer-executable instructions are stored, and when executed by a processor, the computer-executable instructions are used to implement any one of the first aspects. method described.
  • the invention completes the target speed and distance measurement by performing a Fourier transform on the echo, thereby improving the real-time performance of the algorithm and making the algorithm structure easy to implement.
  • FIG1 is a schematic diagram of a system principle of a linear frequency modulation pulse radar provided by an embodiment of the present invention.
  • Figure 2 is a schematic diagram of a method for obtaining Doppler frequency and target echo distance delay from the spectrum in an embodiment of the present invention.
  • Figure 3 is a spectrum diagram of the positive frequency part after echo signal processing in the embodiment of the present invention.
  • the chirp radar multi-period echo signal is first mixed with the transmitted signal, and then undergoes fast Fourier transformation, which will form a peak at its pulse repetition frequency and pulse repetition frequency harmonic position, and the Doppler caused by the moving target The effect will shift the peak position, and the shift amount is the Doppler frequency.
  • the resolution is the pulse signal repetition frequency, and the accuracy of obtaining the difference frequency is low.
  • algorithms such as spectrum correction need to be used to further estimate the difference frequency.
  • the present invention proposes an efficient LFM radar target detection method, that is, a linear frequency modulation pulse radar target detection method.
  • FIG. The schematic diagram of the linear frequency modulation pulse radar target detection system provided by the present invention is shown in FIG. As shown in 1.
  • Step 1 Use linear frequency modulation pulse signal generation to generate a linear frequency modulation pulse signal with a bandwidth of B, a radio frequency frequency of fG, an FM slope of ⁇ , a pulse repetition frequency of f PRF and a duty cycle of 50%.
  • Step 2 Receive the multi-period target echo signal through the receiving antenna, and mix the echo signal with the linear frequency modulation pulse signal in step 1.
  • Step 3 After mixing, the signal passes through a low-pass filter (LPF) to obtain a difference frequency signal.
  • the difference frequency signal is sampled by ADC to obtain a sampling signal.
  • the sampling frequency is f s .
  • Step 4 The above sampled signal is used as input to the subsequent digital signal processor. Perform FFT processing on the sampled signal to obtain the spectrum.
  • Step 5 The schematic diagram of the method of extracting the Doppler frequency and the difference frequency caused by the echo range delay from the spectrum obtained in step 4 is shown in Figure 2.
  • the solid line is the spectrum after processing the echo of a stationary target
  • the dotted line is the spectrum after processing the echo of a moving target at the same position. It can be seen that after processing, the echo of a stationary target will form a peak at the harmonic position of the pulse repetition frequency, and the closer the position is to the true difference frequency, the higher the peak value will be. However, after processing the echo of a moving target, the peak position will be affected by Doppler. The effect is offset.
  • the peak echo position of a target close to the radar shifts to the right of the harmonic position, while the peak echo position of a target far away from the radar shifts to the left side of the harmonic. Therefore, the difference between the frequency corresponding to the maximum value of the target echo signal after processing and the harmonic frequency of the nearest pulse repetition frequency is the Doppler frequency caused by the target's movement speed, which is represented as f d in the figure. Then, through the maximum value of the spectrum and its position, the position and amplitude of the two peaks on the left and right of the maximum value, and the spectrum correction algorithm, the frequency value f diff of the difference frequency signal processed by the linear frequency modulation pulse radar based on mixing is obtained.
  • the chirp signal provided is a chirp radar with a duty cycle of 50%.
  • the spectrum correction method used for the chirp pulse signal with a duty cycle of 50% is as follows: If the maximum value corresponds to The peak amplitude on the right side of the frequency is greater than the left side, the formula is:
  • f max is the frequency corresponding to the maximum value
  • f PRF is the pulse repetition frequency
  • X max is the maximum value of the spectrum amplitude
  • X left and X right are the corresponding position spectral line amplitudes after the two harmonic shifts to the left and right of the maximum value respectively.
  • Step 6 Obtain the target speed v and target distance information R through f ⁇ and f d in step 5.
  • the formula is as follows:
  • c is the speed of light
  • ⁇ is the frequency modulation slope
  • f G is the radio frequency carrier frequency
  • the echo signal is processed by the signal processing step of the present invention to obtain a spectrum as shown in FIG3 .
  • the target speed is obtained according to the Doppler frequency.
  • the difference frequency signal frequency f diff 13.3333MHz is obtained.
  • the method of the present invention can complete the measurement of the target speed and distance after a Fourier transform, and the result error is small, successfully reducing the complexity of the original algorithm, and the method of the present invention has a simple structure and is easy to implement.
  • the above example is for the speed and distance detection of a single target. If it is the speed and distance detection of multiple targets, similar processing can be done.

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  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

一种线性调频脉冲雷达的目标探测方法，包括获取雷达发射信号和目标回波信号；对雷达发射信号和目标回波信号混频、滤波、采样后进行一次快速傅里叶变换获得信号频谱；通过信号频谱中峰值所对应频率，以及与最近的发射信号脉冲重频的谐波频率获取目标运动引起的多普勒频率，计算目标速度；通过对雷达发射信号和目标回波信号进行差频估计；通过差频估计与多普勒频率获取目标回波距离延时引起的差频，计算得到目标距离信息。通过对回波进行一次傅里叶变换后完成目标速度距离测量，在提高算法实时性的同时使算法结构易于实现。

Description

一种线性调频脉冲雷达的目标探测方法
本发明要求于2022年09月19日提交中国专利局、申请号为202211136573.8、发明名称为“一种线性调频脉冲雷达的目标探测方法”的中国专利申请的优先权，其全部内容通过引用结合在本发明中。
技术领域
本发明涉及雷达领域，尤其涉及在线性调频雷达中，具体涉及一种线性调频脉冲雷达的目标探测方法。
背景技术
线性调频雷达可以使用回波信号与发射信号的差频进行目标距离量测，但差频同样会受运动目标速度影响，因此会出现距离多普勒耦合现象。
传统方法此时需对回波信号进行二维傅里叶变换处理，该信号处理算法结构复杂，算法复杂度高。
如何更快速、高效测量目标的速度和距离信息，值得研究。
发明内容
本发明目的在于提供一种线性调频脉冲雷达的目标探测方法。
本发明解决传统方法信号处理算法结构复杂，算法复杂度高的问题，简化算法过程，本发明将LFM雷达多个周期接收信号与发射波形进行混频，然后对所有混频后信号进行采样并进行傅里叶变换。
在本发明的雷达体制中，目标回波在经过与原线性调频连续波混频后，只需进行一次一维快速傅里叶变换(FFT)，便可测量目标的速度和距离信息。
本发明通过下述技术方案实现：
第一方面，本发明提供一种线性调频脉冲雷达的目标探测方法，其特征在于，包括：
获取雷达发射信号和目标回波信号；
对雷达发射信号和目标回波信号依次进行混频、滤波、采样后进行一次快速傅里叶变换获得信号频谱；
通过信号频谱获取多普勒频率，并计算目标速度；
通过对所述雷达发射信号和目标回波信号进行差频估计，得到所述目标回波信号与雷达发射信号的估计差频；
通过所述多普勒频率和所述估计差频获取目标回波距离延时引起的延时差频；
通过所述估计差频与所述延时差频，计算得到目标距离信息。
第二方面，本发明提供一种线性调频脉冲雷达的目标探测方法，包括：
获取雷达发射信号和目标回波信号；
对雷达发射信号和目标回波信号混频、滤波、采样后进行一次快速傅里叶变换获得信号频谱；
所述信号频谱中峰值所对应频率，以及与其最近的发射信号脉冲重复频率的谐波频率获取目标运动引起的多普勒频率，计算目标速度；
通过对所述雷达发射信号和目标回波信号进行差频估计。通过所述差频与所述多普勒频率获取目标回波距离延时引起的差频，计算得到目标距离信息。
优选的，其中，所述雷达发射信号为通过信号发生器产生的线性调频脉冲信号。
优选的，所述通过信号频谱获取多普勒频率，并计算目标速度，包括：
依据所述信号频谱中峰值对应的频率，以及与所述峰值最近的发射信号脉冲重频的谐波频率获取目标运动引起的多普勒频率，多普勒频率为所述峰值对应的频率与所述峰值对应的频率最近的谐波频率之差；依据多普勒频率，计算目标速度。
优选的，通过对所述雷达发射信号和目标回波信号进行差频估计，通过所述差频估计与多普勒频率获取目标回波距离延时引起的差频，计算得到目标距离信息，包括：
通过频谱校正获取目标回波信号与雷达发射信号估计的差频，再通过所述多普勒频率获取回波距离延时引起的差频，回波距离延时引起的差频为所述回波信号与发射信号估计的差频与所述多普勒频率之差。
优选的，本发明提供的一种线性调频脉冲雷达的目标探测方法，具体步骤如下：
步骤1：运用线性调频脉冲信号发生器产生带宽为B，射频频率fG，调频斜率为μ，脉冲重复频率为fPRF，占空比为50％的线性调频脉冲信号；
步骤2：通过接收天线，接收多周期目标回波信号，将回波信号与步骤1 产生的线性调频脉冲信号进行混频；
步骤3：混频后信号经过低通滤波器获得差频信号，差频信号经过ADC采样得到采样信号，采样频率为fs；
步骤4：数字信号处理器对采样信号进行FFT处理获得频谱；
步骤5：从步骤4得到的频谱中提取多普勒频率及回波信号和发射信号差频，选定目标回波信号经处理后最大值所对应频率与最大值所对应频率最近的脉冲重频的谐波频率的差值即为目标运动速度引起的多普勒频率fd，通过频谱最大值及位置、最大值左右两峰值位置及幅值、频谱校正算法，获得基于混频的线性调频脉冲雷达处理后的差频信号频值fdiff，线性调频脉冲雷达中，目标回波距离延时引起的差频fτ＝fdiff-fd；
步骤6：通过步骤5中的fτ及fd获得目标速度v与目标距离信息R。
第三方面，本发明提供一种线性调频脉冲雷达的目标探测装置，包括：
线性调频脉冲信号发生器，用于向目标发射雷达发射信号；
混频器，用于对目标发射信号和回波信号混频；
滤波器，用于对目标发射信号和回波信号混频后的信号进行滤波；
ADC，用于对混频、滤波后的信号进行采样；
快速傅里叶模块，用于对滤波后的信号进行一次快速傅里叶变换获得信号频谱；
计算模块用于从所述频谱获取目标距离及速度，具体包括：通过所述信号频谱中峰值所对应频率，以及与其最近的发射信号脉冲重频的谐波频率获取目标运动引起的多普勒频率，计算目标速度；通过对所述雷达发射信号和目标回波信号进行差频估计；通过所述差频与所述多普勒频率获取目标回波距离延时引起的差频，计算得到目标距离信息。
第四方面，一种电子设备，包括：处理器，以及与所述处理器通信连接的存储器；
所述存储器存储计算机执行指令；
所述处理器执行所述存储器存储的计算机执行指令，实现如第一方面中任一项所述的方法。
第五方面，一种计算机程序产品，包括计算机程序，该计算机程序被处理 器或芯片执行时实现如第一方面中任一项所述的方法。
第六方面，本发明提供一种计算机可读存储介质，所述计算机可读存储介质中存储有计算机执行指令，所述计算机执行指令被处理器执行时用于实现如第一方面任一项所述的方法。
本发明具有如下的优点和有益效果：
本发明通过对回波进行一次傅里叶变换后完成目标速度距离测量，在提高算法实时性的同时使算法结构易于实现。
附图说明
此处所说明的附图用来提供对本发明实施例的进一步理解，构成本发明的一部分，并不构成对本发明实施例的限定。在附图中：
图1为本发明实施例提供的一种线性调频脉冲雷达的系统原理示意图。
图2为本发明实施例中从所述频谱获取多普勒频率及目标回波距离延时方法示意图。
图3为本发明实施例中回波信号处理后正频率部分频谱图。
具体实施方式
在对本发明的任意实施例进行详细的描述之前，应该理解本发明的应用不局限于下面的说明或附图中所示的结构的细节。本发明可采用其它的实施例，并且可以以各种方式被实施或被执行。基于本发明中的实施例，本领域普通技术人员在没有做出创造性改进前提下所获得的所有其它实施例，均属于本发明保护的范围。
首先，线性调频雷达多周期回波信号首先与发射信号混频，然后进行快速傅里叶变换后，会在其脉冲重复频率及脉冲重频谐波位置形成峰值，而运动目标造成的多普勒效应会使峰值位置发生偏移，偏移量即为多普勒频率。在使用此频谱计算接收信号与发射信号差频时，分辨率为脉冲信号重复频率，获得差频频率精度较低。为提升精度，还需使用频谱校正等算法对差频频率进行进一步估计。
因此，本发明基于上述信号特性，提出一种高效LFM雷达目标探测方法，即一种线性调频脉冲雷达的目标探测方法。
本发明的提供的一种线性调频脉冲雷达目标探测的系统原理示意图如图 1所示。
本发明的具体实施步骤如下：
步骤1：运用线性调频脉冲信号发生产生带宽为B，射频频率fG，调频斜率为μ，脉冲重复频率为fPRF，占空比为50％的线性调频脉冲信号。
步骤2：通过接收天线，接收多周期目标回波信号，回波信号与步骤1的线性调频脉冲信号进行混频。
步骤3：混频后信号经过低通滤波器(LPF)获得差频信号，差频信号经过ADC采样得到采样信号，采样频率为fs。
步骤4：上述采样信号作为后续数字信号处理器输入。对采样信号进行FFT处理获得频谱。
步骤5：从步骤4得到的频谱中提取多普勒频率及回波距离延时引起的差频的方法的示意图如图2所示。图2中，实线为静止目标回波处理后频谱，虚线为同一位置运动目标回波处理后频谱。可以看到，静止目标的回波经处理后会在脉冲重复频率的谐波位置形成峰值，且越靠近真实差频的位置峰值越高，而运动目标回波处理后峰值位置会因多普勒效应发生偏移。具体表现为靠近雷达的目标回波峰值位置偏移至谐波位置右侧，而远离雷达的目标回波峰值位置偏移至谐波左侧。因此，目标回波信号经处理后最大值所对应频率与其最近的脉冲重频的谐波频率的差值即为目标运动速度引起的多普勒频率，图中表示为fd。然后，通过频谱最大值及其位置、最大值左右两峰值位置及幅值、频谱校正算法，获得基于混频的线性调频脉冲雷达处理后的差频信号频值fdiff。
在本发明实施例中，提供的线性调频脉冲信号为占空比为50％的线性调频脉冲雷达，对占空比为50％的线性调频脉冲信号采用的频谱校正方法如下：如果最大值所对应频率右侧峰值幅值大于左侧，公式为：
反之，公式为：
其中，fmax为最大值对应频率，fPRF为脉冲重复频率，Xmax为频谱幅值最大值，Xleft、Xright分别为最大值左右两个谐波偏移后对应位置谱线幅值。当线 性调频脉冲雷达占空比不为50％时，需要使用其他的频谱校正算法计算fdiff，与本发明计算逻辑类似，本发明不再赘述。其中，线性调频脉冲雷达中，fdiff＝fτ+fd，因此目标回波距离延时引起的差频fτ＝fdiff-fd。
步骤6：通过步骤5中的fτ及fd获得目标速度v与目标距离信息R，公式如下：

其中，c为光速，μ为调频斜率，fG为射频载波频率。
实施例：
设待测目标距离R＝1km，速度v＝50m/s，信噪比SNR＝-10dB使用传统线性调频信号雷达对该目标进行探测时，无法在一次FFT获得目标精确的速度与距离信息。而使用本发明的探测方法，便可降低算法复杂度，且硬件结构简单。
设置脉冲信号重复频率fPRF＝50kHz，产生线性调频信号的带宽B＝20MHz，射频频率fG＝10GHz，占空比为50％，脉冲时宽为10μs。调频斜率μ＝2BfPRF＝2×1012，回波信号采样频率fs＝40MHz，单次处理采集30周期回波数据。上述参数设置雷达中，回波信号经本发明信号处理步骤处理后获得频谱如图3所示，频谱最大值所对应频率为13353.3kHz，与最近谐波偏移量为3.3kHz，即多普勒频率fd＝3.3kHz，根据多普勒频率求得目标速度运用频谱校正及频谱最大值，最大值左右两峰值位置及幅值，获得差频信号频率fdiff＝13.3333MHz。根据fdiff及fd获得回波距离延时差频fτ＝fdiff-fd＝13.33MHz，进一步求得目标距离
从上述结果可以看出本发明的方法可以在一次傅里叶变换后完成对目标速度和距离的测量，且结果误差较小，成功降低原有算法复杂度，且本发明方法结构简单，易于实现。上述举例针对的是单目标的速度、距离检测，若为多目标的速度、距离检测，可做类似处理。
以上所述的具体实施方式，对本发明的目的、技术方案和有益效果进行了进一步详细说明，所应理解的是，以上所述仅为本发明的具体实施方式而已， 并不用于限定本发明的保护范围，凡在本发明的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (10)

  1. 一种线性调频脉冲雷达的目标探测方法，其特征在于，包括：
    获取雷达发射信号和目标回波信号；
    对雷达发射信号和目标回波信号依次进行混频、滤波、采样后进行一次快速傅里叶变换获得信号频谱；
    通过信号频谱获取多普勒频率，并计算目标速度；
    通过对所述雷达发射信号和目标回波信号进行差频估计，得到所述目标回波信号与雷达发射信号的估计差频；
    通过所述多普勒频率和所述估计差频获取目标回波距离延时引起的延时差频；
    通过所述估计差频与所述延时差频，计算得到目标距离信息。
  2. 一种线性调频脉冲雷达的目标探测方法，其特征在于，包括：
    获取雷达发射信号和目标回波信号；
    对雷达发射信号和目标回波信号混频、滤波、采样后进行一次快速傅里叶变换获得信号频谱；
    通过信号频谱获取多普勒频率，并计算目标速度；
    通过对所述雷达发射信号和目标回波信号进行差频估计，通过所述差频估计与多普勒频率获取目标回波距离延时引起的差频，计算得到目标距离信息。
  3. 根据权利要求2所述的方法，其特征在于，其中，所述雷达发射信号为通过信号发生器产生线性调频脉冲信号。
  4. 根据权利要求2所述的方法，其特征在于，所述通过信号频谱获取多普勒频率，并计算目标速度，包括：
    依据所述信号频谱中峰值对应的频率，以及与所述峰值最近的发射信号脉冲重频的谐波频率获取目标运动引起的多普勒频率，多普勒频率为所述峰值对应的频率与所述峰值对应的频率最近的谐波频率之差；依据多普勒频率，计算目标速度。
  5. 根据权利要求2所述的方法，其特征在于，通过对所述雷达发射信号和目标回波信号进行差频估计，通过所述差频估计与多普勒频率获取目标回波距离延时引起的差频，计算得到目标距离信息，包括：
    通过频谱校正获取目标回波信号与雷达发射信号估计的差频，再通过所述多普勒频率获取回波距离延时引起的差频，回波距离延时引起的差频为所述回波信号与发射信号估计的差频与所述多普勒频率之差。
  6. 根据权利要求2-5任一所述的方法，其特征在于，包括步骤如下：
    步骤1：运用线性调频脉冲信号发生产生带宽为B，射频频率fG，调频斜率为μ，脉冲重复频率为fPRF，占空比为50％的线性调频脉冲信号；
    步骤2：通过接收天线，接收多周期目标回波信号，回波信号与步骤1的线性调频脉冲信号进行混频；
    步骤3：混频后信号经过低通滤波器获得差频信号，差频信号经过ADC采样得到采样信号，采样频率为fs；
    步骤4：数字信号处理器对采样信号进行FFT处理获得频谱；
    步骤5：从步骤4得到的频谱中提取多普勒频率及回波信号和发射信号差频，选定目标回波信号经处理后最大值所对应频率与最大值所对应频率最近的脉冲重频的谐波频率的差值即为目标运动速度引起的多普勒频率fd，通过频谱最大值及位置、最大值左右两峰值位置及幅值、频谱校正算法，获得基于混频的线性调频脉冲雷达处理后的差频信号频值fdiff，线性调频脉冲雷达中，目标回波距离延时引起的差频fτ＝fdiff-fd；
    步骤6：通过步骤5中的fτ及fd获得目标速度v与目标距离信息R。
  7. 一种线性调频脉冲雷达的目标探测装置，其特征在于，包括：
    线性调频脉冲信号发生器，用于向目标发射雷达发射信号；
    混频器，用于对雷达发射信号和目标回波信号混频；
    滤波器，用于对雷达发射信号和目标回波信号混频后的信号进行滤波；
    ADC，用于对混频、滤波后的信号进行采样；
    快速傅里叶模块，用于对滤波后的信号进行一次快速傅里叶变换获得信号频谱；
    计算模块，用于从所述频谱获取目标距离及速度，具体包括:通过所述信号频谱中峰值所对应频率，以及与其最近的发射信号脉冲重频的谐波频率获取目标运动引起的多普勒频率，计算目标速度；通过对所述雷达发射信号和目标回波信号 进行差频估计；通过所述差频与所述多普勒频率获取目标回波距离延时引起的差频，计算得到目标距离信息。
  8. 一种计算机程序产品，其特征在于，包括计算机程序，该计算机程序被处理器或芯片执行时实现如权利要求2至5中任一项所述的方法。
  9. 一种计算机可读存储介质，其特征在于，包所述计算机可读存储介质中存储有计算
    机执行指令，所述计算机执行指令被处理器执行时用于实现如权利要求1至5中任一项所述的方法。
  10. 一种电子设备，其特征在于，包括：处理器，以及与所述处理器通信连接的存储器；所述存储器存储计算机执行指令；
    所述处理器执行所述存储器存储的计算机执行指令，实现如权利要求2至5中任一项所述的方法。
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