阅读说明：本技术 雷达运动目标检测方法、装置及存储介质 (Radar moving target detection method and device and storage medium ) 是由 黄磊 袁伟健 赵博 谢晓宇 黄聪 包为民 于 2020-07-08 设计创作，主要内容包括：本发明公开了一种雷达运动目标检测方法,包括：对LFMCW雷达回波信号进行去斜脉冲压缩处理,以获得回波差拍信号,对回波差拍信号依次进行MTI动目标显示处理、MTD动目标检测处理以及恒虚警率检测处理,以确定目标谱线；对所述目标谱线进行峰值搜索,以确定目标谱线中的运动目标对应的正扫频阶段的第一距离和第一速度,以及负扫频阶段的第二距离和第二速度；基于所述第一距离、第一速度、第二距离和第二速度,确定运动目标的目标距离以及目标速度。本发明还公开了一种雷达运动目标检测装置及存储介质。本发明通过对称正负线性调频连续波体制,利用对称性实现距离和速度解耦合,提高运动目标的距离检测准确率。(The invention discloses a radar moving target detection method, which comprises the following steps: performing deskew pulse compression processing on echo signals of an LFMCW radar to obtain echo beat signals, and sequentially performing MTI moving target display processing, MTD moving target detection processing and constant false alarm rate detection processing on the echo beat signals to determine target spectral lines; performing peak value search on the target spectral line to determine a first distance and a first speed of a positive frequency sweeping stage and a second distance and a second speed of a negative frequency sweeping stage corresponding to a moving target in the target spectral line; and determining the target distance and the target speed of the moving target based on the first distance, the first speed, the second distance and the second speed. The invention also discloses a radar moving target detection device and a storage medium. According to the invention, through a symmetrical positive and negative linear frequency modulation continuous wave system, distance and speed decoupling is realized by using symmetry, and the distance detection accuracy of a moving target is improved.)

1. A radar moving target detection method is characterized by comprising the following steps:

performing deskew pulse compression processing on LFMCW radar echo signals to obtain echo beat signals, wherein the LFMCW radar echo signals comprise echo signals in a positive frequency sweep stage and echo signals in a negative frequency sweep stage;

sequentially carrying out MTI moving target display processing, MTD moving target detection processing and constant false alarm rate detection processing on the echo beat signal to determine a target spectral line;

performing peak value search on the target spectral line to determine a first distance and a first speed of a positive frequency sweeping stage and a second distance and a second speed of a negative frequency sweeping stage corresponding to a moving target in the target spectral line;

and determining the target distance and the target speed of the moving target based on the first distance, the first speed, the second distance and the second speed.

2. The radar moving target detection method of claim 1 wherein performing a peak search on the target spectral lines to determine a first distance and a first velocity for a positive sweep phase and a second distance and a second velocity for a negative sweep phase for the moving target in the target spectral lines comprises:

performing peak value search on the target spectral line to determine a first distance coordinate and a first speed coordinate of a positive frequency sweeping stage and a second distance coordinate and a second speed coordinate of a negative frequency sweeping stage corresponding to the moving target;

determining and obtaining range resolution based on the effective bandwidth of the LFMCW radar transmission signal, and determining speed resolution based on the effective time width of the LFMCW radar transmission signal;

determining a first distance based on the first distance coordinate and a distance resolution, determining a second distance based on the second distance coordinate and a distance resolution, determining a first speed based on the first speed coordinate and a speed resolution, and determining a second speed based on the second speed coordinate and a speed resolution.

3. The radar moving target detection method of claim 1 wherein said step of determining a target distance and a target velocity for a moving target based on said first distance, first velocity, second distance, and second velocity comprises:

determining a first echo center frequency in a positive frequency sweeping stage based on the first distance and the first speed, and determining a second echo center frequency in a negative frequency sweeping stage based on the second distance and the second speed;

and determining a target distance and a target speed based on the first echo center frequency and the second echo center frequency.

4. The radar moving target detection method of claim 3 wherein said step of determining a target distance and a target velocity based on said first echo center frequency and said second echo center frequency comprises:

determining a beat frequency value and a Doppler frequency based on the first echo center frequency and the second echo center frequency;

determining the target distance based on the beat frequency value, and determining the target velocity based on the Doppler frequency.

5. The radar moving target detection method of claim 1, wherein the step of sequentially performing MTI moving target display processing, MTD moving target detection processing, and constant false alarm rate detection processing on the echo beat signal to determine a target spectral line comprises:

carrying out Fourier transformation on the echo beat signal, and carrying out MTI moving target display processing on the echo beat signal after Fourier transformation to obtain an echo beat signal after MTI processing;

performing MTD moving target detection processing on the echo beat signals after MTI processing, and performing filtering processing on the echo beat signals after MTD processing through a narrow-band Doppler filtering group to obtain channel data of a plurality of speed channels;

and carrying out constant false alarm rate detection processing on each channel data to determine the target spectral line.

6. The radar moving object detection method of claim 5 wherein said step of performing constant false alarm rate detection processing on each channel data to determine said target spectral line comprises:

performing Fourier transform on each channel data to obtain a range-Doppler matrix corresponding to each channel data;

and carrying out two-dimensional unit average constant false alarm rate detection on each range-Doppler matrix to determine the target spectral line.

7. The radar moving target detection method of claim 6 wherein said step of performing two-dimensional unit-averaged constant false alarm rate detection on each range-doppler matrix to determine said target spectral line comprises:

determining the mean value of all units in the training unit corresponding to each Doppler matrix, and determining the detection threshold value corresponding to each Doppler matrix based on each mean value;

and determining the target spectral line based on the detection unit corresponding to each Doppler matrix and the detection threshold.

8. The radar moving target detection method of any one of claims 1 to 7, wherein after the step of determining a target distance and a target velocity of the moving target based on the first distance, the first velocity, the second distance, and the second velocity, further comprising:

and displaying the target distance and the target speed.

9. A radar moving object detecting apparatus, characterized by comprising: memory, a processor and a radar moving object detection program stored on the memory and executable on the processor, the radar moving object detection program, when executed by the processor, implementing the steps of the radar moving object detection method according to any one of claims 1 to 8.

10. A storage medium having stored thereon a radar moving object detection program which, when executed by a processor, implements the steps of the radar moving object detection method according to any one of claims 1 to 8.

Technical Field

The invention relates to the technical field of signal processing, in particular to a radar moving target detection method, a radar moving target detection device and a storage medium.

Background

Compared with the traditional pulse radar, the LFMCW (Linear Frequency Modulated continuous wave) radar has lower transmitting power, and can obtain large signal energy through large time width, thereby achieving a long detection distance. The LFMCW chirp continuous wave radar has the advantages of large bandwidth, large noise coefficient of a system, stronger capability of capturing weak signals and easiness in realizing higher range resolution. Since the LFMCW radar transmits a signal with a much larger time width than the time delay of an echo signal and allows a transmitter and a receiver to work simultaneously, the signal can be transmitted and the echo signal can be received at any time, and a ranging blind area does not exist. However, the chirp signal used by the LFMCW radar belongs to a large time-bandwidth product signal, which causes a distance-velocity coupling phenomenon in an echo signal, so that the resolution of a detection system is reduced, an error between a measured distance and an actual distance of a moving target is large, and the accuracy of detecting the distance of the moving target is low.

The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.

Disclosure of Invention

The invention mainly aims to provide a radar moving target detection method, a radar moving target detection device and a storage medium, and aims to solve the technical problem that the distance detection accuracy rate of the existing radar moving target detection method is low.

In order to achieve the above object, the present invention provides a radar moving target detection method, which includes the following steps:

performing deskew pulse compression processing on LFMCW radar echo signals to obtain echo beat signals, wherein the LFMCW radar echo signals comprise echo signals in a positive frequency sweep stage and echo signals in a negative frequency sweep stage;

sequentially carrying out MTI moving target display processing, MTD moving target detection processing and constant false alarm rate detection processing on the echo beat signal to determine a target spectral line;

performing peak value search on the target spectral line to determine a first distance and a first speed of a positive frequency sweeping stage and a second distance and a second speed of a negative frequency sweeping stage corresponding to a moving target in the target spectral line;

and determining the target distance and the target speed of the moving target based on the first distance, the first speed, the second distance and the second speed.

In an embodiment, the step of performing a peak search on the target spectral line to determine a first distance and a first speed of a positive sweep stage and a second distance and a second speed of a negative sweep stage corresponding to the moving target in the target spectral line includes:

performing peak value search on the target spectral line to determine a first distance coordinate and a first speed coordinate of a positive frequency sweeping stage, and a second distance coordinate and a second speed coordinate of a negative frequency sweeping stage corresponding to the moving target;

determining and obtaining range resolution based on the effective bandwidth of the LFMCW radar transmission signal, and determining speed resolution based on the effective time width of the LFMCW radar transmission signal;

determining a first distance based on the first distance coordinate and a distance resolution, determining a second distance based on the second distance coordinate and a distance resolution, determining a first speed based on the first speed coordinate and a speed resolution, and determining a second speed based on the second speed coordinate and a speed resolution.

In one embodiment, the step of determining the target distance and the target speed of the moving target based on the first distance, the first speed, the second distance and the second speed comprises:

determining a first echo center frequency in a positive frequency sweeping stage based on the first distance and the first speed, and determining a second echo center frequency in a negative frequency sweeping stage based on the second distance and the second speed;

and determining a target distance and a target speed based on the first echo center frequency and the second echo center frequency.

In one embodiment, the step of determining the target distance and the target velocity based on the first echo center frequency and the second echo center frequency comprises:

determining a beat frequency value and a Doppler frequency based on the first echo center frequency and the second echo center frequency;

determining the target distance based on the beat frequency value, and determining the target velocity based on the Doppler frequency.

In an embodiment, the step of sequentially performing MTI moving target display processing, MTD moving target detection processing, and constant false alarm rate detection processing on the echo beat signal to determine a target spectral line includes:

carrying out Fourier transformation on the echo beat signal, and carrying out MTI moving target display processing on the echo beat signal after Fourier transformation to obtain an echo beat signal after MTI processing;

performing MTD moving target detection processing on the echo beat signals after MTI processing, and performing filtering processing on the echo beat signals after MTD processing through a narrow-band Doppler filtering group to obtain channel data of a plurality of speed channels;

and carrying out constant false alarm rate detection processing on each channel data to determine the target spectral line.

In an embodiment, the step of performing constant false alarm rate detection processing on each channel data to determine the target spectral line includes:

fourier transform is carried out on each channel data to obtain a distance Doppler matrix corresponding to each channel data;

and carrying out two-dimensional unit average constant false alarm rate detection on each range-Doppler matrix to determine the target spectral line.

In an embodiment, the step of performing two-dimensional cell average constant false alarm rate detection on each range-doppler matrix to determine the target spectral line includes:

determining the mean value of all units in the training unit corresponding to each Doppler matrix, and determining the detection threshold value corresponding to each Doppler matrix based on each mean value;

and determining the target spectral line based on the detection unit corresponding to each Doppler matrix and the detection threshold.

In an embodiment, after the step of determining the target distance and the target speed of the moving target based on the first distance, the first speed, the second distance, and the second speed, the method further includes:

and displaying the target distance and the target speed.

In addition, to achieve the above object, the present invention also provides a radar moving target detecting device, including: the radar moving object detection method comprises a memory, a processor and a radar moving object detection program which is stored on the memory and can run on the processor, wherein the steps of the radar moving object detection method are realized when the radar moving object detection program is executed by the processor.

In addition, to achieve the above object, the present invention further provides a storage medium having a radar moving object detecting program stored thereon, wherein the radar moving object detecting program, when executed by a processor, implements the steps of the foregoing radar moving object detecting method.

The invention determines an echo beat signal based on an LFMCW radar echo signal, performs MTI moving target display processing on the echo beat signal to obtain a processed echo beat signal, then sequentially performs MTD moving target detection processing and constant false alarm rate detection processing on the echo beat signal to determine a target spectral line, then performs peak search on the target spectral line to determine a first distance and a first speed of a positive frequency sweep stage and a second distance and a second speed of a negative frequency sweep stage corresponding to a moving target in the target spectral line, then determines a target distance and a target speed of the moving target based on the first distance, the first speed, the second distance and the second speed, and decouples the distance and the speed by using symmetry through a symmetrical positive and negative linear frequency modulation continuous wave system to improve the distance detection accuracy of the moving target, meanwhile, the waveform of the broadband linear frequency modulation continuous wave is adopted to solve the contradiction problem of large detection distance and distance resolution, and according to the characteristics of the linear frequency modulation continuous wave, the moving target is separated from the fixed target by adopting a frequency spectrum cancellation technology of subtracting the frequency spectrum of the beat signal in the previous period from the frequency spectrum of the beat signal in the next period.

Drawings

FIG. 1 is a schematic structural diagram of a radar moving target detection device in a hardware operating environment according to an embodiment of the present invention;

FIG. 2 is a schematic flow chart of a radar moving object detection method according to a first embodiment of the present invention;

FIG. 3 is a schematic diagram of moving target display processing of echo signals during a swept frequency phase according to the present invention;

FIG. 4 is a schematic flow chart illustrating MTD processing of an echo beat signal according to the present invention;

FIG. 5 is a schematic diagram of the target distance-velocity after positive sweep phase dynamic MTD processing according to the present invention;

FIG. 6 is a schematic structural diagram of the two-dimensional unit average constant false alarm rate detection process of the present invention;

fig. 7 is a schematic diagram of the distance-velocity of the target after the constant false alarm rate detection process of the present invention.

The implementation, functional features and advantages of the objects of the present invention will be further described with reference to the accompanying drawings.

Detailed Description

It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in fig. 1, fig. 1 is a schematic structural diagram of a radar moving object detection apparatus in a hardware operating environment according to an embodiment of the present invention.

The radar Moving target detection device of the embodiment of the invention can be a PC, and can also be a mobile terminal device with a display function, such as a smart phone, a tablet computer, an electronic book reader, an MP3(Moving Picture Experts Group Audio Layer III, dynamic video Experts compression standard Audio Layer 3) player, an MP4(Moving Picture Experts Group Audio Layer IV, dynamic video Experts compression standard Audio Layer 4) player, a portable computer and the like.

As shown in fig. 1, the radar moving-object detecting apparatus may include: a processor 1001, such as a CPU, a network interface 1004, a user interface 1003, a memory 1005, a communication bus 1002. Wherein a communication bus 1002 is used to enable connective communication between these components. The user interface 1003 may include a Display screen (Display), an input unit such as a Keyboard (Keyboard), and the optional user interface 1003 may also include a standard wired interface, a wireless interface. The network interface 1004 may optionally include a standard wired interface, a wireless interface (e.g., WI-FI interface). The memory 1005 may be a high-speed RAM memory or a non-volatile memory (e.g., a magnetic disk memory). The memory 1005 may alternatively be a storage device separate from the processor 1001.

Optionally, the radar moving object detecting device may further include a camera, a Radio Frequency (RF) circuit, a sensor, an audio circuit, a WiFi module, and the like. Such as light sensors, motion sensors, and other sensors. Specifically, the light sensor may include an ambient light sensor that may adjust the brightness of the display screen according to the brightness of ambient light, and a proximity sensor that may turn off the display screen and/or the backlight when the mobile terminal moves to the ear. As one of the motion sensors, the gravity acceleration sensor can detect the magnitude of acceleration in each direction (generally, three axes), detect the magnitude and direction of gravity when the mobile terminal is stationary, and can be used for applications of recognizing the posture of the mobile terminal (such as horizontal and vertical screen switching, related games, magnetometer posture calibration), vibration recognition related functions (such as pedometer and tapping), and the like; of course, the radar moving object detection device may also be configured with other sensors such as a gyroscope, a barometer, a hygrometer, a thermometer, and an infrared sensor, which are not described herein again.

It will be appreciated by those skilled in the art that the terminal structure shown in fig. 1 does not constitute a limitation of the radar motion target detection means, and may comprise more or less components than those shown, or some components may be combined, or a different arrangement of components.

As shown in fig. 1, a memory 1005, which is one type of computer storage medium, may include an operating system, a network communication module, a user interface module, and a radar moving object detection program therein.

In the radar moving object detection apparatus shown in fig. 1, the network interface 1004 is mainly used for connecting to a background server and performing data communication with the background server; the user interface 1003 is mainly used for connecting a client (user side) and performing data communication with the client; and processor 1001 may be used to invoke a radar moving object detection program stored in memory 1005.

In this embodiment, the radar moving object detecting apparatus includes: a memory 1005, a processor 1001, and a radar moving object detection program stored on the memory 1005 and operable on the processor 1001, wherein when the processor 1001 calls the radar moving object detection program stored in the memory 1005, the following operations are performed:

performing deskew pulse compression processing on LFMCW radar echo signals to obtain echo beat signals, wherein the LFMCW radar echo signals comprise echo signals in a positive frequency sweep stage and echo signals in a negative frequency sweep stage;

sequentially carrying out MTI moving target display processing, MTD moving target detection processing and constant false alarm rate detection processing on the echo beat signal to determine a target spectral line;

performing peak value search on the target spectral line to determine a first distance and a first speed of a positive frequency sweeping stage and a second distance and a second speed of a negative frequency sweeping stage corresponding to a moving target in the target spectral line;

and determining the target distance and the target speed of the moving target based on the first distance, the first speed, the second distance and the second speed.

Further, the processor 1001 may call the radar motion target detection program stored in the memory 1005, and further perform the following operations:

performing peak value search on the target spectral line to determine a first distance coordinate and a first speed coordinate of a positive frequency sweeping stage, and a second distance coordinate and a second speed coordinate of a negative frequency sweeping stage corresponding to the moving target;

determining and obtaining range resolution based on the effective bandwidth of the LFMCW radar transmission signal, and determining speed resolution based on the effective time width of the LFMCW radar transmission signal;

determining a first distance based on the first distance coordinate and a distance resolution, determining a second distance based on the second distance coordinate and a distance resolution, determining a first speed based on the first speed coordinate and a speed resolution, and determining a second speed based on the second speed coordinate and a speed resolution.

Further, the processor 1001 may call the radar motion target detection program stored in the memory 1005, and further perform the following operations:

determining a first echo center frequency in a positive frequency sweeping stage based on the first distance and the first speed, and determining a second echo center frequency in a negative frequency sweeping stage based on the second distance and the second speed;

and determining a target distance and a target speed based on the first echo center frequency and the second echo center frequency.

Further, the processor 1001 may call the radar motion target detection program stored in the memory 1005, and further perform the following operations:

determining a beat frequency value and a Doppler frequency based on the first echo center frequency and the second echo center frequency;

determining the target distance based on the beat frequency value, and determining the target velocity based on the Doppler frequency.

Further, the processor 1001 may call the radar motion target detection program stored in the memory 1005, and further perform the following operations:

carrying out Fourier transformation on the echo beat signal, and carrying out MTI moving target display processing on the echo beat signal after Fourier transformation to obtain an echo beat signal after MTI processing;

performing MTD moving target detection processing on the echo beat signals after MTI processing, and performing filtering processing on the echo beat signals after MTD processing through a narrow-band Doppler filtering group to obtain channel data of a plurality of speed channels;

and carrying out constant false alarm rate detection processing on each channel data to determine the target spectral line.

Further, the processor 1001 may call the radar motion target detection program stored in the memory 1005, and further perform the following operations:

fourier transform is carried out on each channel data to obtain a distance Doppler matrix corresponding to each channel data;

and carrying out two-dimensional unit average constant false alarm rate detection on each range-Doppler matrix to determine the target spectral line.

Further, the processor 1001 may call the radar motion target detection program stored in the memory 1005, and further perform the following operations:

determining the mean value of all units in the training unit corresponding to each Doppler matrix, and determining the detection threshold value corresponding to each Doppler matrix based on each mean value;

and determining the target spectral line based on the detection unit corresponding to each Doppler matrix and the detection threshold.

Further, the processor 1001 may call the radar motion target detection program stored in the memory 1005, and further perform the following operations:

and displaying the target distance and the target speed.

The invention also provides a radar moving target detection method, and referring to fig. 2, fig. 2 is a schematic flow chart of a first embodiment of the radar moving target detection method of the invention.

It should be noted that, the formula of the positive frequency sweep stage of the LFMCW radar transmission signal is:

correspondingly, the formula of the LFMCW radar echo signal positive frequency sweeping stage is as follows:

then, the formula of the echo beat signal in the positive frequency sweeping phase is:

the formula of the beat complex signal of the echo beat signal in the positive frequency sweeping stage is as follows:

performing Fourier transform (FFT) on the beat complex signal processed by the rectangular window function to obtain a frequency domain formula of the echo beat signal in the positive frequency sweep stage, wherein the frequency domain formula is as follows:

further, the conversion relationship of frequency and distance: f is 2 mu R/c;

the conversion relationship between frequency and speed is: f. of_d＝2υ/λ；

The distance resolution is: Δ R ═ c/2B;

the velocity resolution is: Δ upsilon ═ λ/2T;

the center frequency of the echo in the positive sweep frequency stage is as follows: f. of_b,up≈2μR₀/c+2υf₀/c；

Similarly, the echo center frequency in the negative frequency sweeping stage is as follows: f. of_b,down≈2μR₀/c-2υf₀/c；

According to the distance deviation of the measurement target in the positive frequency sweeping stage and the negative frequency sweeping stageThe symmetry of the shift quantity can obtain a beat frequency value corresponding to the actual distance of the target, wherein the beat frequency value is as follows: f. of_b＝(f_b,up+f_b,down)/2；

The Doppler frequency is: f. of_d＝(f_b,up-f_b,down)/2；

Further, it is possible to prevent the occurrence of,

obtaining the movement speed of the target: θ λ (f)_b,up-f_b,down)/4。

Wherein, the direction far from the radar is set as the positive direction, A₀Representing the amplitude of the signal, phi_0，upRepresenting an initial phase; f. of₀Is the carrier frequency center frequency, T is the effective bandwidth of the transmitted signal, μ is the chirp rate, B represents the effective time width of the transmitted signal, where μ is B/T; kr is related to the reflection intensity and propagation attenuation of the target;

an additional phase shift induced for target reflections; r₀Is the target distance; and the echo time delay tau (t) is 2(R + upsilont t)/c, and upsilon is the radial speed of the target to be measured.

In this embodiment, the radar moving target detection method includes:

step S101, performing deskew pulse compression processing on an LFMCW radar echo signal to obtain an echo beat signal, wherein the LFMCW radar echo signal comprises an echo signal in a positive frequency sweeping stage and an echo signal in a negative frequency sweeping stage;

in this embodiment, an echo signal received by the LFMCW radar is obtained first, and the echo signal of the LFMCW radar is determined according to the echo signal, where the echo signal of the LFMCW radar includes an echo signal in a positive frequency sweep stage (a positive linear frequency modulation frequency sweep band or an up frequency sweep band) and an echo signal in a negative frequency sweep stage (a negative linear frequency modulation frequency sweep band, a down frequency sweep band) and an up frequency sweep stage.

Next, performing deskew pulse compression processing on the LFMCW radar echo signal to obtain an echo beat signal, and specifically, performing deskew pulse compression processing on the echo signal in the positive frequency sweep stage and the echo signal in the negative frequency sweep stage respectively to obtain the echo beat signal in the positive frequency sweep stage and the echo beat signal in the negative frequency sweep stage.

Step S102, MTI moving target display processing, MTD moving target detection processing and constant false alarm rate detection processing are sequentially carried out on the echo beat signal to determine a target spectral line;

in this embodiment, after the echo beat signal is obtained, MTI moving target display processing, MTD moving target detection processing, and constant false alarm rate detection processing are sequentially performed on the echo beat signal to determine a target spectral line. Specifically, MTI moving target display processing is performed on the echo beat signals to obtain processed echo beat signals, MTD moving target detection processing is performed on the processed echo beat signals to obtain channel data of a plurality of speed channels, and then constant false alarm rate detection processing is performed on each channel data to determine target spectral lines corresponding to each channel data.

Step S103, performing peak value search on the target spectral line to determine a first distance and a first speed of a positive frequency sweep stage and a second distance and a second speed of a negative frequency sweep stage corresponding to a moving target in the target spectral line;

in this embodiment, after a target spectral line is obtained, a peak search is performed on the target spectral line, so as to determine, according to a result of the peak search, a first distance and a first speed of a positive frequency sweep stage corresponding to a moving target, and a second distance and a second speed of a negative frequency sweep stage, specifically, the peak search is performed on the spectral line of the positive frequency sweep stage in the target spectral line, so as to determine a first speed coordinate and a first distance coordinate corresponding to the moving target, and the first distance and the first speed are determined according to the first speed coordinate and the first distance coordinate, and similarly, the second distance and the second speed are determined according to the spectral line of the negative frequency sweep stage in the target spectral line.

And step S104, determining the target distance and the target speed of the moving target based on the first distance, the first speed, the second distance and the second speed.

In this embodiment, after obtaining the first distance, the first speed, the second distance, and the second speed, the target distance and the target speed of the moving target are determined based on the first distance, the first speed, the second distance, and the second speed, specifically, the first echo center frequency in the positive sweep stage is calculated based on the first distance and the first speed, the second echo center frequency in the negative sweep stage is calculated based on the second distance and the second speed, and the target distance and the target speed are determined based on the first echo center frequency and the second echo center frequency.

Further, in an embodiment, after step S104, the radar moving target detection method further includes:

and displaying the target distance and the target speed.

In this embodiment, the target distance and the target speed of each moving target may be displayed on the display interface, for example, the target distance of each moving target is displayed in one display area, and the target speed of the moving target is displayed in another display area.

It should be noted that the code corresponding to the processing flow of this embodiment may be burned into the TMS 320C 6748 signal processor, which is a high-performance 32-bit DSP processor proposed by Texas Instruments (TI) corporation, and the floating-point operation is performed with the dominant frequency of 456 MHz. The TMS 320C 6748 processor contains 2 CPUs of 150MHz, the size of a built-in memory is 448k, and EMAC, MMC/SD, video I/O, LCD Ctr, USB, UPP, SATA, I2C, SPI, UART (SCI) and the like are mainly and externally arranged. So as to realize the display of the target distance and the target speed of the moving target through the LCD screen of the DSP signal processing system.

The radar moving target detection method provided by this embodiment obtains a processed echo beat signal by performing deskew pulse compression processing on an LFMCW radar echo signal, then sequentially performing MTI moving target display processing, MTD moving target detection processing, and constant false alarm rate detection processing on the echo beat signal to determine a target spectral line, then performing peak search on the target spectral line to determine a first distance and a first speed of a positive frequency sweep stage and a second distance and a second speed of a negative frequency sweep stage corresponding to a moving target in the target spectral line, then determining a target distance and a target speed of the moving target based on the first distance, the first speed, the second distance, and the second speed, and decoupling the distance and the speed by using symmetry through a symmetrical positive and negative linear frequency modulation continuous wave system to improve the distance detection accuracy of the moving target, meanwhile, the waveform of the broadband linear frequency modulation continuous wave is adopted to solve the problem of contradiction between large detection distance and distance resolution, and according to the characteristics of the linear frequency modulation continuous wave, the moving target and the fixed target are separated by adopting a frequency spectrum cancellation technology of subtracting the frequency spectrum of the beat signal in the previous period from the frequency spectrum of the beat signal in the next period.

Based on the first embodiment, a second embodiment of the radar moving target detection method of the present invention is proposed, in this embodiment, step S103 includes:

step S201, performing peak value search on the target spectral line to determine a first distance coordinate and a first speed coordinate of a positive frequency sweeping stage and a second distance coordinate and a second speed coordinate of a negative frequency sweeping stage corresponding to the moving target;

step S202, determining and obtaining range resolution based on effective bandwidth of LFMCW radar emission signals, and determining speed resolution based on effective time width of the LFMCW radar emission signals;

step S203, determining a first distance based on the first distance coordinate and the distance resolution, determining a second distance based on the second distance coordinate and the distance resolution, determining a first speed based on the first speed coordinate and the speed resolution, and determining a second speed based on the second speed coordinate and the speed resolution.

In this embodiment, peak search is performed on each target spectral line to determine a first distance coordinate and a first speed coordinate of a positive frequency sweep stage, and a second distance coordinate and a second speed coordinate of a negative frequency sweep stage, which correspond to the moving target. Specifically, peak searching is carried out on a spectral line in a positive frequency sweeping stage in a target spectral line, the position of a first peak in the spectral line is determined, namely a distance axis coordinate and a speed axis coordinate corresponding to the first peak in the spectral line are obtained, and then the first distance coordinate and the first speed coordinate of the positive frequency sweeping stage corresponding to a moving target are obtained; meanwhile, peak value searching is carried out on the spectral line of the negative frequency sweeping stage in the target spectral line, the position of the second peak value in the spectral line is determined, namely the distance axis coordinate and the speed axis coordinate corresponding to the second peak value in the spectral line are obtained, and further the second distance coordinate and the second speed coordinate of the negative frequency sweeping stage corresponding to the moving target are obtained.

Determining and obtaining range resolution based on the effective bandwidth of the LFMCW radar transmitting signal, and determining speed resolution based on the effective time width of the LFMCW radar transmitting signal; specifically, the distance resolution and the speed resolution are calculated based on the speed of light c, the wavelength λ of the transmission signal, the effective bandwidth T of the transmission signal, and the effective time width B of the transmission signal.

Then, a first distance is determined based on the first distance coordinate and the distance resolution, a second distance is determined based on the second distance coordinate and the distance resolution, a first speed is determined based on the first speed coordinate and the speed resolution, and a second speed is determined based on the second speed coordinate and the speed resolution. Specifically, the first distance is a first distance coordinate distance resolution, the second distance is a second distance coordinate distance resolution, the first velocity is a first velocity coordinate velocity resolution, and the second velocity is a second velocity coordinate velocity resolution.

In the radar moving target detection method provided by this embodiment, a peak value search is performed on the target spectral line to determine a first distance coordinate and a first speed coordinate of a positive frequency sweep stage and a second distance coordinate and a second speed coordinate of a negative frequency sweep stage, which correspond to a moving target; determining and obtaining range resolution based on the effective bandwidth of the LFMCW radar transmission signal, and determining speed resolution based on the effective time width of the LFMCW radar transmission signal; and then determining a first distance based on the first distance coordinate and the distance resolution, determining a second distance based on the second distance coordinate and the distance resolution, determining a first speed based on the first speed coordinate and the speed resolution, and determining a second speed based on the second speed coordinate and the speed resolution, so that the first distance and the first speed of a positive frequency sweeping stage and the second distance and the second speed of a negative frequency sweeping stage corresponding to the moving target can be accurately obtained, and the distance detection accuracy of the moving target is further improved.

Based on the first embodiment, a third embodiment of the radar moving target detection method of the present invention is proposed, in this embodiment, step S104 includes:

step S201, determining a first echo center frequency in a positive frequency sweep stage based on the first distance and the first speed, and determining a second echo center frequency in a negative frequency sweep stage based on the second distance and the second speed;

step S302, determining a target distance and a target speed based on the first echo center frequency and the second echo center frequency.

In this embodiment, after the first distance, the first speed, the second distance, and the second speed are obtained, the first echo center frequency in the positive frequency sweep stage and the second echo center frequency in the negative frequency sweep stage are calculated according to the formula of the echo center frequency in the positive frequency sweep stage and the formula of the echo center frequency in the negative frequency sweep stage, and then the target distance and the target speed are determined based on the first echo center frequency and the second echo center frequency, so that the target distance and the target speed are accurately obtained according to the echo center frequency.

Wherein the first echo center frequency f_b,upThe formula of (1) is: f. of_b,up≈2μR₀₁/c+2υ₁f₀/c，R₀₁Is a first distance, upsilon₁Is the first speed. Center frequency f of second echo_b,downThe formula of (1) is: f. of_b,down≈2μR₀₂/c-2υ₂f₀/c，R₀₂Is a first distance, upsilon₂Is the first speed.

Further, in an embodiment, step S302 includes:

step S303, determining a beat frequency value and a doppler frequency based on the first echo center frequency and the second echo center frequency;

step S304, determining the target distance based on the beat frequency value, and determining the target speed based on the Doppler frequency.

Specifically, the formula of the beat frequency value is: f. of_b＝(f_b,up+f_b,down) The formula of the doppler frequency is: f. of_d＝(f_b,up-f_b,down)/2。

The target distance is then determined from the beat frequency value, and the target velocity is determined based on the doppler frequency.

In the radar moving target detection method provided in this embodiment, the first echo center frequency in the positive frequency sweep stage is determined based on the first distance and the first speed, the second echo center frequency in the negative frequency sweep stage is determined based on the second distance and the second speed, and then the target distance and the target speed are determined based on the first echo center frequency and the second echo center frequency, so that the target distance and the target speed of the moving target are accurately obtained according to the echo center frequency, and the distance detection accuracy of the moving target is further improved.

Based on the first embodiment, a fourth embodiment of the radar moving target detection method of the present invention is proposed, in this embodiment, step S102 includes:

step S401, Fourier transformation is carried out on the echo beat signal, MTI moving target display processing is carried out on the echo beat signal after Fourier transformation, and the echo beat signal after MTI processing is obtained;

step S402, MTD moving target detection processing is carried out on the echo beat signals after MTI processing, and filtering processing is carried out on the echo beat signals after MTD processing through a narrow-band Doppler filtering group to obtain channel data of a plurality of speed channels;

step S403, performing constant false alarm rate detection processing on each channel data to determine a target spectral line corresponding to each channel data.

In this embodiment, after the echo beat signal is obtained, fourier transform is performed on the echo beat signal, MTI moving target display processing is performed on the echo beat signal after fourier transform to obtain an echo beat signal after MTI processing, the echo beat signal in the positive sweep stage is obtained by subtracting the signal spectrum in the previous cycle from the signal spectrum in the next cycle from the echo signal in the positive sweep stage after fourier transform, and the echo beat signal in the negative sweep stage is obtained by subtracting the signal spectrum in the previous cycle from the signal spectrum in the next cycle from the echo signal in the negative sweep stage after fourier transform, for example,

ΔS_up,k(f)＝S_up,k(f)-S_up,k-1(f)；

wherein S is_up,k(f) The signal spectrum of the kth period in the echo signal of the positive frequency sweeping stage after Fourier transform; s_up,k-1(f) The signal spectrum of the k-1 cycle in the echo signal of the positive frequency sweeping stage after Fourier transformation. And, if it is a stationary target, Δ S_up,k(f) 0; if it is a moving object, Δ S_up,k(f)≠0。

Referring to FIG. 3, FIG. 3 is a schematic diagram illustrating moving target display processing of an echo signal during a normal frequency sweeping phase according to the present invention; the distances of the three moving targets are respectively 50m, 120m and 150m, the corresponding speeds are 5m/s, 3m/s and-4 m/s (the direction far away from the radar is the positive direction), the distance of the fixed target is 80m, and the corresponding speed is 0 m/s. The uppermost range spectrogram and the middle range spectrogram in fig. 3 are range spectrums of echo signals of two adjacent cycles, and the lowermost range spectrogram in fig. 3 is a range spectrum of a post-MTI echo beat signal. As can be seen from the lowermost range spectrogram in fig. 3, the frequency spectrums of the echo beat signals of the fixed targets of the post-MTI range millimeter wave radar 80m have been cancelled, and the frequency spectrums of the three moving targets remain.

Then, MTD moving target detection processing is carried out on the echo beat signal after MTI processing, filtering processing is carried out on the echo beat signal after MTD processing through a narrow-band Doppler filtering group to obtain channel data of a plurality of speed channels, referring to FIG. 4, MTD processing is carried out on the echo signal in a positive frequency sweeping stage after MTI processing and the echo signal in a negative frequency sweeping stage after MTI processing respectively to carry out FFT processing on the frequency spectrums of the echo beat signal of frequency sweeping in all periods in the same distance unit, then frequency spectrums corresponding to different speeds in the positive frequency sweeping stage and the negative frequency sweeping stage are obtained through distance storage of MTD and fixed target cancellation, then the frequency spectrums corresponding to different speeds in the positive frequency sweeping stage are input into a filter group to obtain frequency sweeping channel data of a plurality of speed channels corresponding to the positive frequency sweeping stage, and inputting the frequency spectrums corresponding to different speeds in the negative frequency sweeping stage into a filter bank to obtain channel data of a plurality of speed channels corresponding to the negative frequency sweeping stage so as to realize the separation of moving targets at different speeds. Referring to fig. 5, fig. 5 is a schematic diagram of the target distance-velocity after the positive sweep phase dynamic MTD processing according to the present invention.

And then, performing constant false alarm rate detection processing on each channel data to determine a target spectral line corresponding to each channel data.

In the radar moving target detection method provided by this embodiment, fourier transform is performed on an echo beat signal, and MTI moving target display processing is performed on the echo beat signal after fourier transform, so as to obtain an echo beat signal after MTI processing; and then, MTD moving target detection processing is carried out on the echo beat signals after MTI processing, MTD moving target detection processing is carried out on the echo beat signals after MTD processing, filtering processing is carried out on the processed echo beat signals through a narrow-band Doppler filtering group to obtain channel data of a plurality of speed channels, constant false alarm rate detection processing is carried out on each channel data to determine target spectral lines corresponding to each channel data, moving targets with different speeds can be classified through the narrow-band Doppler filtering group, background clutter is eliminated through constant false alarm detection, and the distance detection accuracy of the moving targets is further improved.

A fifth embodiment of the radar moving object detecting method of the present invention is proposed based on the fourth embodiment, and in this embodiment,

step S401, Fourier transform is carried out on each channel data to obtain a range Doppler matrix corresponding to each channel data;

step S402, two-dimensional unit average constant false alarm rate detection is carried out on each range-Doppler matrix to determine a target spectral line corresponding to each channel data.

In this embodiment, when obtaining each channel data, fourier transform is performed on each channel data, specifically, fourier transform is performed on each channel data in Doppler dimension, so as to obtain a range-Doppler matrix corresponding to each channel data.

And then, carrying out two-dimensional unit average constant false alarm rate detection on each distance Doppler matrix to determine a target spectral line corresponding to each channel data, and further accurately obtaining the target spectral line.

Further, step S402 includes:

step S403, determining the mean values of all units in the training unit corresponding to each Doppler matrix, and determining the detection threshold value corresponding to each Doppler matrix based on each mean value;

step S404, determining a target spectral line corresponding to each channel data based on the detection unit corresponding to each doppler matrix and the detection threshold.

In this embodiment, first, a detection Threshold corresponding to each doppler matrix is calculated, referring to fig. 6, the average constant false alarm rate detection of the two-dimensional unit in fig. 6 includes a detection unit, a protection unit, and a training unit, all units in the training unit are summed and averaged to obtain an average value, and the average value is multiplied by a Threshold factor to obtain a detection Threshold, so as to obtain a detection Threshold corresponding to each doppler matrix;

then, determining a target spectral line corresponding to each channel data based on the detection unit and the detection Threshold corresponding to each doppler matrix, specifically, comparing the detection value of the detection unit corresponding to each doppler matrix with the detection Threshold, if the detection value is greater than Threshold, judging that a moving target appears, using the spectral line corresponding to the doppler matrix as a target spectral line, and outputting the amplitude and the serial number of the spectral line; if the detection value is less than or equal to Threshold, setting the amplitude of the spectral line corresponding to the Doppler matrix to zero and outputting the zero amplitude and the serial number of the spectral line.

Referring to fig. 7, it is clear from comparing fig. 7 with fig. 5 that the influence of background noise and interference variation is obviously eliminated after the two-dimensional constant false alarm rate detection processing.

In the radar moving target detection method provided by this embodiment, fourier transform is performed on each channel data to obtain a range-doppler matrix corresponding to each channel data; and then, carrying out two-dimensional unit average constant false alarm rate detection on each distance Doppler matrix to determine a target spectral line corresponding to each channel data, thereby realizing elimination of background clutter through the two-dimensional unit average constant false alarm rate detection and further improving the distance detection accuracy of the moving target.

In addition, an embodiment of the present invention further provides a storage medium, where a radar moving object detection program is stored on the storage medium, and when executed by a processor, the radar moving object detection program implements the following operations:

performing deskew pulse compression processing on LFMCW radar echo signals to obtain echo beat signals, wherein the LFMCW radar echo signals comprise echo signals in a positive frequency sweep stage and echo signals in a negative frequency sweep stage;

sequentially carrying out MTI moving target display processing, MTD moving target detection processing and constant false alarm rate detection processing on the echo beat signal to determine a target spectral line;

performing peak value search on the target spectral line to determine a first distance and a first speed of a positive frequency sweeping stage and a second distance and a second speed of a negative frequency sweeping stage corresponding to a moving target in the target spectral line;

and determining the target distance and the target speed of the moving target based on the first distance, the first speed, the second distance and the second speed.

Further, the radar moving object detection program when executed by the processor further implements the following operations:

performing peak value search on the target spectral line to determine a first distance coordinate and a first speed coordinate of a positive frequency sweeping stage, and a second distance coordinate and a second speed coordinate of a negative frequency sweeping stage corresponding to the moving target;

determining and obtaining range resolution based on the effective bandwidth of the LFMCW radar transmission signal, and determining speed resolution based on the effective time width of the LFMCW radar transmission signal;

determining a first distance based on the first distance coordinate and a distance resolution, determining a second distance based on the second distance coordinate and a distance resolution, determining a first speed based on the first speed coordinate and a speed resolution, and determining a second speed based on the second speed coordinate and a speed resolution.

Further, the radar moving object detection program when executed by the processor further implements the following operations:

determining a first echo center frequency in a positive frequency sweeping stage based on the first distance and the first speed, and determining a second echo center frequency in a negative frequency sweeping stage based on the second distance and the second speed;

and determining a target distance and a target speed based on the first echo center frequency and the second echo center frequency.

Further, the radar moving object detection program when executed by the processor further implements the following operations:

determining a beat frequency value and a Doppler frequency based on the first echo center frequency and the second echo center frequency;

determining the target distance based on the beat frequency value, and determining the target velocity based on the Doppler frequency.

Further, the radar moving object detection program when executed by the processor further implements the following operations:

carrying out Fourier transformation on the echo beat signal, and carrying out MTI moving target display processing on the echo beat signal after Fourier transformation to obtain an echo beat signal after MTI processing;

performing MTD moving target detection processing on the echo beat signals after MTI processing, and performing filtering processing on the echo beat signals after MTD processing through a narrow-band Doppler filtering group to obtain channel data of a plurality of speed channels;

and carrying out constant false alarm rate detection processing on each channel data to determine the target spectral line.

Further, the radar moving object detection program when executed by the processor further implements the following operations:

fourier transform is carried out on each channel data to obtain a distance Doppler matrix corresponding to each channel data;

and carrying out two-dimensional unit average constant false alarm rate detection on each range-Doppler matrix to determine the target spectral line.

Further, the radar moving object detection program when executed by the processor further implements the following operations:

determining the mean value of all units in the training unit corresponding to each Doppler matrix, and determining the detection threshold value corresponding to each Doppler matrix based on each mean value;

and determining the target spectral line based on the detection unit corresponding to each Doppler matrix and the detection threshold.

Further, the radar moving object detection program when executed by the processor further implements the following operations:

and displaying the target distance and the target speed.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or system that comprises the element.

The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.

Through the above description of the embodiments, those skilled in the art will clearly understand that the method of the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but in many cases, the former is a better embodiment. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium (e.g., ROM/RAM, magnetic disk, optical disk) as described above and includes instructions for enabling a terminal device (e.g., a mobile phone, a computer, a server, an air conditioner, or a network device) to execute the method according to the embodiments of the present invention.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the present specification and drawings, or used directly or indirectly in other related fields, are included in the scope of the present invention.