CN108776330B - High-precision calibration method and device for multiple receiving channels of FMCW radar - Google Patents

Abstract

The present application discloses a high-precision calibration method and device for FMCW radar with multiple receiving channels. The method provided by the present application calculates the amplitude compensation factor, the complex carrier factor and the phase compensation factor. Perform amplitude calibration, range gate calibration and phase calibration on the signal of the calibration channel respectively to ensure the consistency of multiple channels, which is beneficial to improve the target detection capability and angle measurement capability of the radar, and solves the existing lack of a multi-channel radar. The technical problem of the method of high-precision calibration of the receiving channel to improve the target detection ability and angle measurement accuracy.

Description

A high-precision calibration method and device for FMCW radar multiple receiving channels

technical field

The present application relates to the technical field of radar, and in particular, to a high-precision calibration method and device for FMCW radar with multiple reception channels.

Background technique

Frequency Modulated Continuous Wave (FMCW, Frequency Modulated Wave) is a high-precision radar ranging technology. Its basic principle is that the transmitted wave is a high-frequency continuous wave. The frequency of transmission is the same as the law of triangular wave. The time difference of the echo signal can be used to calculate the target distance. Because FMCW technology has the advantages of no distance blind spot, high resolution and low transmission power, it is widely used in industrial measurement and control, security, missile guidance, weather detection, wall detection, mine detection systems, collision avoidance systems and other related fields.

之后，很容易就得到目标的方位角θ，如图5至图7所示，从目标反射的平面波到天线入口处的波程差为ΔR，两个天线之间的距离为d，因此可以得出ΔR＝d·sinθ，结合相位差与波程差的关系

可以得出目标的方位角

虽然以上获得目标方位角的过程并不复杂，但是以上目标方位角的计算结果准确的前提是两个接收通道对接收信号的延迟是一致的，并且相位差的计算一般是通过信号的正交分解后计算求得的，这也需要两个通道的接收增益要完全一致，但是，由于器件的离散性和PCB制板误差，对于模拟电路组成的接收链路而言，两个接收通道的群延迟和增益都完全一致是不可能实现的，而如果接收通道的一致性不能达到要求，会导致依赖多通道接收来实现的高级信号处理算法的性能下降甚至失效，因此，需要提供一种高精度的校准方法对模拟通道进行校准，提高目标检出能力和测角精度。With the increasing requirements for signal processing of multi-receiving channel diversity or target angle measurement, the importance of calibration of multiple receiving channels has become more and more prominent. For multi-channel radar angle measurement, as shown in Figures 5 to 7, The target is located at the angle θ of the normal direction of the radar antenna. Assume that there are two receiver channels, receiving channel A and receiving channel B. The characteristics of these two receiving channels are exactly the same. From the antenna entrance to the receiver output, the signal The delay is exactly the same, and the gain of the signal is exactly the same, then, the phase difference measured by the two receiving channels

After that, the azimuth angle θ of the target can be easily obtained. As shown in Figure 5 to Figure 7, the wave path difference from the plane wave reflected from the target to the entrance of the antenna is ΔR, and the distance between the two antennas is d, so it can be obtained Out ΔR=d·sinθ, combined with the relationship between the phase difference and the wave path difference

The azimuth of the target can be obtained

Although the above process of obtaining the target azimuth is not complicated, the premise of the accurate calculation of the above target azimuth is that the delay of the two receiving channels to the received signal is consistent, and the phase difference The calculation is generally obtained by the orthogonal decomposition of the signal, which also requires the receiving gain of the two channels to be exactly the same. However, due to the discreteness of the device and the error of the PCB board, for the receiving chain composed of analog circuits In other words, it is impossible to achieve exactly the same group delay and gain of the two receiving channels, and if the consistency of the receiving channels cannot meet the requirements, the performance of advanced signal processing algorithms that rely on multi-channel receiving will be degraded or even invalid. Therefore, it is necessary to provide a high-precision calibration method to calibrate the analog channel, so as to improve the target detection ability and the angle measurement accuracy.

SUMMARY OF THE INVENTION

The embodiments of the present application provide a high-precision calibration method and device for FMCW radar multiple receiving channels, which solves the lack of a method for high-precision calibration of radar multiple receiving channels and improves target detection capability and angle measurement accuracy. technical issues.

In view of this, a first aspect of the present application provides a high-precision calibration method for FMCW radar multiple receiving channels, the method comprising:

101. Obtain the first echo signal of the standard receiving channel and the second echo signal of the calibration receiving channel when the radar wave reflector and the plane where the receiving antenna is located are separated by a first preset distance;

是FMCW信号的斜率；102. Obtain a first gain of the first echo signal and a second gain of the second echo signal, use the quotient of the second gain and the first gain as an amplitude compensation factor, and obtain the first gain. The first phase error φ ₁ of the first echo signal and the second echo signal, and the complex carrier factor e ^-j2πτkt is preset, where τ is the time delay of the calibration receiving channel relative to the target echo of the standard receiving channel,

is the slope of the FMCW signal;

103. Obtain the third echo signal of the standard receiving channel and the fourth echo signal of the calibration receiving channel when the radar wave reflector is at a second preset distance from the plane, wherein the first echo signal is 2. The preset distance is not equal to the first preset distance;

T为雷达探测目标回波的双程路径时延及在标准接收通道上的延迟总和，T₁为第一预置距离时的雷达波反射器回波的双程路径时延及在标准接收通道上的延迟总和，T₂为第二预置距离时的雷达波反射器回波的双程路径时延及在标准接收通道上的延迟总和；104. Obtain the second phase error φ ₂ between the third echo signal and the fourth echo signal, and calculate the phase compensation factor according to the first phase error φ ₁ and the second phase error φ ₂ The formula calculates the phase compensation factor, and the calculation formula of the phase compensation factor is

T is the two-way path delay of the radar detection target echo and the sum of the delays on the standard receiving channel, T ₁ is the two-way path delay of the radar wave reflector echo at the first preset distance and the delay on the standard receiving channel. T ₂ is the two-way path delay of the radar wave reflector echo at the second preset distance and the delay sum of the standard receiving channel;

105. Multiply the amplitude compensation factor by the standard signal amplitude of the standard receiving channel to calibrate the signal amplitude of the calibration channel, and multiply the complex carrier factor by the time-domain signal of the calibration channel to the calibration channel signal. The distance gate is calibrated, and the phase of the calibration channel signal is calibrated by taking the difference between the phase of the standard channel signal and the phase compensation factor as the phase of the calibration channel signal.

Preferably, after step 104 and before step 105, it further includes:

106. Store the amplitude compensation factor, the complex carrier factor, and the phase compensation factor.

Preferably, step 102 specifically includes:

是FMCW信号的斜率。Obtain the first gain of the first echo signal and the second gain of the second echo signal, use the quotient of the second gain and the first gain as an amplitude compensation factor, Fourier transform is performed on the wave signal and the second echo signal to obtain a first Fourier transform signal and a second Fourier transform signal respectively, and the first Fourier transform signal and the second Fourier transform signal are obtained. The phase difference of the Lie transform signal is taken as the first phase error φ ₁ , and the complex carrier factor e ^-j2πτkt is preset, where τ is the time delay of the calibration receiving channel relative to the target echo of the standard receiving channel,

is the slope of the FMCW signal.

Preferably, step 104 specifically includes:

T为雷达探测目标回波的双程路径时延及在标准接收通道上的延迟总和，T₁为第一预置距离时的雷达波反射器回波的双程路径时延及在标准接收通道上的延迟总和，T₂为第二预置距离时的雷达波反射器回波的双程路径时延及在标准接收通道上的延迟总和。Fourier transform is performed on the third echo signal and the fourth echo signal to obtain a third Fourier transform signal and a fourth Fourier transform respectively, and the third Fourier transform signal and the fourth Fourier transform are obtained. The phase difference of the fourth Fourier transform signal is used as the second phase error φ ₂ , and the phase compensation factor is calculated by the phase compensation factor calculation formula according to the first phase error φ ₁ and the second phase error φ ₂ , the calculation formula of the phase compensation factor is

T is the two-way path delay of the radar detection target echo and the sum of the delays on the standard receiving channel, T ₁ is the two-way path delay of the radar wave reflector echo at the first preset distance and the delay on the standard receiving channel. T ₂ is the sum of the two-way path delay of the radar wave reflector echo at the second preset distance and the delay sum of the standard receiving channel.

A second aspect of the present application provides a high-precision calibration device for FMCW radar with multiple reception channels, the device comprising:

a first acquisition module, configured to acquire the first echo signal of the standard receiving channel and the second echo signal of the calibration receiving channel when the radar wave reflector is at a first preset distance from the plane where the receiving antenna is located;

是FMCW信号的斜率；A second obtaining module, configured to obtain a first gain of the first echo signal and a second gain of the second echo signal, and use the quotient of the second gain and the first gain as an amplitude compensation factor , obtain the first phase error φ ₁ of the first echo signal and the second echo signal, and preset the complex carrier factor e ^-j2πτkt , where τ is the target echo of the calibration receiving channel relative to the standard receiving channel time delay,

is the slope of the FMCW signal;

a third acquisition module, configured to acquire the third echo signal of the standard receiving channel and the fourth echo signal of the calibration receiving channel when the radar wave reflector is at a second preset distance from the plane, Wherein, the second preset distance is not equal to the first preset distance;

a fourth obtaining module, configured to obtain a second phase error φ ₂ between the third echo signal and the fourth echo signal, and according to the first phase error φ ₁ and the second phase error φ ₂ , The phase compensation factor is calculated by the phase compensation factor calculation formula, and the phase compensation factor calculation formula is: T is the two-way path delay of the radar detection target echo and the sum of the delays on the standard receiving channel, T ₁ is the two-way path delay of the radar wave reflector echo at the first preset distance and the delay on the standard receiving channel. T ₂ is the two-way path delay of the radar wave reflector echo at the second preset distance and the delay sum of the standard receiving channel;

A calibration module, configured to multiply the amplitude compensation factor by the standard signal amplitude of the standard receiving channel to calibrate the signal amplitude of the calibration channel, and multiply the complex carrier factor by the time domain signal of the calibration channel to calibrate the calibration channel The distance gate of the channel signal is calibrated, and the phase of the calibration channel signal is calibrated by taking the difference between the phase of the standard channel signal and the phase compensation factor as the phase of the calibration channel signal.

Preferably, the device further comprises:

A storage module, configured to store the amplitude compensation factor, the complex carrier factor and the phase compensation factor.

Preferably, the second acquisition module is specifically used for:

是FMCW信号的斜率。Obtain the first gain of the first echo signal and the second gain of the second echo signal, use the quotient of the second gain and the first gain as an amplitude compensation factor, Fourier transform is performed on the wave signal and the second echo signal to obtain a first Fourier transform signal and a second Fourier transform signal respectively, and the first Fourier transform signal and the second Fourier transform signal are obtained. The phase difference of the Lie transform signal is taken as the first phase error φ ₁ , and the complex carrier factor e ^-j2πτkt is preset, where τ is the time delay of the calibration receiving channel relative to the target echo of the standard receiving channel,

is the slope of the FMCW signal.

Preferably, the fourth acquisition module is specifically used for:

T为雷达探测目标回波的双程路径时延及在标准接收通道上的延迟总和，T₁为第一预置距离时的雷达波反射器回波的双程路径时延及在标准接收通道上的延迟总和，T₂为第二预置距离时的雷达波反射器回波的双程路径时延及在标准接收通道上的延迟总和。Fourier transform is performed on the third echo signal and the fourth echo signal to obtain a third Fourier transform signal and a fourth Fourier transform respectively, and the third Fourier transform signal and the fourth Fourier transform are obtained. The phase difference of the fourth Fourier transform signal is used as the second phase error φ ₂ , and the phase compensation factor is calculated by the phase compensation factor calculation formula according to the first phase error φ ₁ and the second phase error φ ₂ , the calculation formula of the phase compensation factor is

T is the two-way path delay of the radar detection target echo and the sum of the delays on the standard receiving channel, T ₁ is the two-way path delay of the radar wave reflector echo at the first preset distance and the delay on the standard receiving channel. T ₂ is the sum of the two-way path delay of the radar wave reflector echo at the second preset distance and the delay sum of the standard receiving channel.

A third aspect of the present application provides a computer-readable storage medium, where the computer-readable storage medium is used to store program codes, and the program codes are used to execute any of the above-mentioned high-precision calibration methods for FMCW radar multiple reception channels.

A fourth aspect of the present application provides a computer program product including instructions, which, when run on a computer, enables the computer to execute any of the above-mentioned high-precision calibration methods for multiple receiving channels of an FMCW radar.

As can be seen from the above technical solutions, the present application has the following advantages:

The application provides a high-precision calibration method for FMCW radar with multiple receiving channels. When the radar wave reflector is at a first preset distance from the plane where the receiving antenna is located, the first echo signal of the standard receiving channel and the calibration receiving channel are obtained. The second echo signal of the phase error, and preset the complex carrier factor, and then obtain the third echo signal of the standard receiving channel and the fourth echo signal of the calibration receiving channel when the radar wave reflector and the plane where the receiving antenna is located are separated by the second preset distance, Calculate the second phase error according to the third echo signal and the fourth echo signal, then calculate the phase compensation factor according to the first phase error and the second phase error through the phase compensation factor calculation formula, and multiply the amplitude compensation factor by the standard receiving channel The standard signal amplitude of the calibration channel is calibrated to ensure the consistency of the gain; the complex carrier factor is multiplied by the time domain signal of the calibration channel to calibrate the distance gate of the calibration channel signal, because the frequency domain frequency shift of the signal can be equal to The effect is the time-domain carrier shift, so multiply the time-domain signal of the calibration channel by the complex carrier factor, and then convert the time-domain signal into a frequency-domain signal, which can compensate for the distance gate error between the standard receiving channel and the calibration receiving channel; The difference between the phase of the standard channel signal and the phase compensation factor is used as the phase of the calibration channel signal to calibrate the phase of the calibration channel signal, thereby ensuring the phase consistency. The method provided by the present application, by calculating the amplitude compensation factor, the complex carrier factor and the phase compensation factor, and respectively performing the amplitude calibration, the distance gate calibration and the phase calibration on the signal of the calibration channel through the amplitude compensation factor, the complex carrier factor and the phase compensation factor, ensuring that The multi-channel consistency is beneficial to improve the radar's target detection ability and angle measurement ability, and solves the lack of a method for high-precision calibration of radar multi-receiving channels to improve target detection ability and angle measurement accuracy. technical issues.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present application more clearly, the following briefly introduces the drawings that are used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

1 is a schematic flowchart of an embodiment of a high-precision calibration method for FMCW radar multiple receiving channels provided by the application;

2 is a schematic flowchart of another embodiment of a high-precision calibration method for FMCW radar multiple receiving channels provided by the application;

3 is a schematic structural diagram of a high-precision calibration device for FMCW radar with multiple reception channels provided by the present application;

4 is a schematic diagram of multi-channel calibration of a high-precision calibration method for FMCW radar multiple receiving channels provided by the application;

Figure 5 is a schematic block diagram of the FMCW radar circuit;

FIG. 6 is a schematic diagram of the transmitted signal and the echo signal of the FMCW radar ranging principle;

FIG. 7 is a schematic diagram of the principle of angle measurement of two receiving channels.

Detailed ways

In order to make those skilled in the art better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only It is a part of the embodiments of this application, but not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art under the premise of lack of creative work fall within the protection scope of this application.

This application designs a high-precision calibration method and device for FMCW radar with multiple receiving channels. By calculating the amplitude compensation factor, the complex carrier factor and the phase compensation factor, the amplitude compensation factor, the complex carrier factor and the phase compensation factor are respectively used to calibrate the calibration channel. Signal amplitude calibration, range gate calibration and phase calibration ensure the multi-channel calibration accuracy, which is beneficial to improve the radar's target detection ability and angle measurement ability, and solves the existing lack of a high-precision radar multi-receiving channel. Technical issues of calibration, methods to improve target detection ability and goniometric accuracy.

For ease of understanding, please refer to FIG. 1 and FIG. 4 , an embodiment of a high-precision calibration method for FMCW radar multiple receiving channels provided by the present application includes:

Step 101: Acquire the first echo signal of the standard receiving channel and the second echo signal of the calibration receiving channel when the radar wave reflector is at a first preset distance from the plane where the receiving antenna is located.

接收通道A的增益为

接收通道B的增益为

则接收通道A接收到的第一回波信号和接收通道B接收到的第二回波信号经过下变频后的基带信号分别为

和

其中，τ是校准接收通道相对标准接收通道的目标回波的时延，是FMCW信号的斜率，T为雷达探测目标回波的双程路径时延及在标准接收通道上的延迟总和。It should be noted that for a system with N (N≥2) receiving channels, one channel needs to be selected as the standard receiving channel, and the responses of the other N-1 receiving channels and the standard receiving channel need to be calibrated to achieve the response of all receiving channels. For the same purpose, without loss of generality, in the embodiment of the present application, two receiving channels are taken as an example, as shown in FIG. The radar detector is placed in the normal direction of the radar antenna, and the center of the radar wave reflector is aligned with the center of the receiving antenna, the distance between the radar wave reflector and the receiving antenna satisfies the far-field condition, and the transmitted signal of the target is

The gain of receive channel A is

The gain of receive channel B is

Then the baseband signals of the first echo signal received by receiving channel A and the second echo signal received by receiving channel B after down-conversion are respectively:

and

where τ is the time delay of the calibration receiving channel relative to the target echo of the standard receiving channel, is the slope of the FMCW signal, T is the two-way path delay of the radar detection target echo and the sum of the delay on the standard receiving channel.

是FMCW信号的斜率。Step 102: Obtain the first gain of the first echo signal and the second gain of the second echo signal, use the quotient of the second gain and the second gain as an amplitude compensation factor, and obtain the first echo signal and the second echo The first phase error of the signal is φ ₁ , and the complex carrier factor e ^-j2πτkt is preset, where τ is the time delay of the calibration receiving channel relative to the target echo of the standard receiving channel,

is the slope of the FMCW signal.

是FMCW信号的斜率。It should be noted that after obtaining the first echo signal and the second echo signal, the first gain of the first echo signal and the second gain of the second echo signal can be obtained directly. , taking the quotient of the second gain of the second echo signal and the first gain of the first echo signal as the amplitude compensation factor, and calculating the difference between the phase of the first echo signal and the phase of the second echo signal, the first a phase error φ ₁ , and at the same time, preset the complex carrier factor e ^-j2πτkt used to calibrate the two-channel distance gate, where τ is the time delay of the calibration receiving channel relative to the target echo of the standard receiving channel,

is the slope of the FMCW signal.

Step 103: Obtain the third echo signal of the standard receiving channel and the fourth echo signal of the calibration receiving channel when the radar wave reflector is at a second preset distance from the plane, wherein the second preset distance is not equal to the first preset distance. set distance.

可以看出，方位角的计算仅与多通道的相位差

和距离d有关，即，在通道间距离d固定的情况下，方位角与相位差是一一对应的，通过相位差可以确定目标的方位，而实际上这种方位角测定方式是不准确的，因为目标与接收通道的距离也会影响到接收信号的相位，因此，要实现多通道接收信号相位的精确校准，还需要将目标距离考虑进去，因此，本申请实施例还增加了获取雷达波反射器与平面相距第二预置距离时，标准接收通道的第三回波信号和校准接收通道的第四回波信号，其中，第二预置距离不等于第一预置距离，本申请实施例中的第一预置距离和第二预置距离可以根据实际应用进行设置，在此不进行具体限定。It should be noted that the first phase error φ ₁ obtained in step 102 is related to the initial frequency f _min of FMCW, and is also related to the signal slope k of FMCW, the two-way path delay of the radar detection target echo, and the receiver channel A. The total delay T is related to the time delay τ of the target echo of receiving channel B relative to receiving channel A. τ is caused by the hardware inconsistency of the receiving antenna and receiving channel, such as the difference in PCB wiring or the internal process of components, etc. The path delays caused by the reasons are different. For a manufactured circuit product, the delay τ on each channel is fixed (the error caused by temperature is not considered, and the error caused by temperature is relatively small and can be ignored). Wait for the measuring instrument to measure. According to the existing multi-channel angle measurement principle, as shown in Figure 5 to Figure 7, the azimuth angle is calculated as

It can be seen that the calculation of the azimuth angle is only related to the phase difference of the multi-channel

It is related to the distance d, that is, when the distance d between the channels is fixed, the azimuth angle and the phase difference are in a one-to-one correspondence, and the azimuth of the target can be determined by the phase difference, but in fact, this azimuth angle determination method is inaccurate , because the distance between the target and the receiving channel will also affect the phase of the received signal. Therefore, to achieve accurate calibration of the phase of the multi-channel received signal, the target distance needs to be taken into account. Therefore, the embodiment of the present application also increases the acquisition of radar waves. When the reflector is separated from the plane by a second preset distance, the third echo signal of the standard receiving channel and the fourth echo signal of the calibration receiving channel, wherein the second preset distance is not equal to the first preset distance, this application implements The first preset distance and the second preset distance in the example can be set according to actual applications, which are not specifically limited here.

T为雷达探测目标回波的双程路径时延及在标准接收通道上的延迟总和，T₁为第一预置距离时的雷达波反射器回波的双程路径时延及在标准接收通道上的延迟总和，T₂为第二预置距离时的雷达波反射器回波的双程路径时延及在标准接收通道上的延迟总和。Step 104: Obtain the second phase error φ ₂ between the third echo signal and the fourth echo signal, and calculate the phase compensation factor by using the phase compensation factor calculation formula according to the first phase error φ ₁ and the second phase error φ ₂ , The formula for calculating the phase compensation factor is

T is the two-way path delay of the radar detection target echo and the sum of the delays on the standard receiving channel, T ₁ is the two-way path delay of the radar wave reflector echo at the first preset distance and the delay on the standard receiving channel. T ₂ is the sum of the two-way path delay of the radar wave reflector echo at the second preset distance and the delay sum of the standard receiving channel.

T为雷达探测目标回波的双程路径时延及在标准接收通道上的延迟总和，T₁为第一预置距离时的雷达波反射器回波的双程路径时延及在标准接收通道上的延迟总和，T₂为第二预置距离时的雷达波反射器回波的双程路径时延及在标准接收通道上的延迟总和。根据相位补偿因子计算公式可以计算相位补偿因子，显而易见地，相位补偿因子仅与第一相位误差、第二相位误差和雷达探测目标回波的双程路径时延及在标准接收通道上的延迟总和有关，与接收通道B相对接收通道A的目标回波的时延τ无关。It should be noted that, in the embodiment of the present application, after the third echo signal and the fourth echo signal are obtained, in the same way, the third echo signal and the fourth echo signal may be subjected to the same procedure as the first echo signal and the fourth echo signal. The same signal processing of the second echo signal is used to obtain the second phase error φ ₂ between the third echo signal and the fourth echo signal. By calculating the first phase error φ ₁ and the second phase error φ ₂ The calculation formulas are combined, and the calculation formula of the phase compensation factor can be obtained.

T is the two-way path delay of the radar detection target echo and the sum of the delays on the standard receiving channel, T ₁ is the two-way path delay of the radar wave reflector echo at the first preset distance and the delay on the standard receiving channel. T ₂ is the sum of the two-way path delay of the radar wave reflector echo at the second preset distance and the delay sum of the standard receiving channel. The phase compensation factor can be calculated according to the calculation formula of the phase compensation factor. Obviously, the phase compensation factor is only related to the sum of the first phase error, the second phase error, the two-way path delay of the radar detection target echo and the delay on the standard receiving channel It is related and has nothing to do with the time delay τ of receiving channel B relative to the target echo of receiving channel A.

Step 105: Multiply the amplitude compensation factor by the standard signal amplitude of the standard receiving channel to calibrate the amplitude of the calibration channel signal, multiply the complex carrier factor by the time domain signal of the calibration channel to calibrate the distance gate of the calibration channel signal, and convert the standard channel signal The difference between the phase of and the phase compensation factor is used as the phase of the calibration channel signal to calibrate the phase of the calibration channel signal.

It should be noted that, in the embodiment of the present application, the signal amplitude of the calibration channel is calibrated by multiplying the amplitude compensation factor by the standard signal amplitude of the standard receiving channel, which can ensure the consistency of the gain; the complex carrier factor is multiplied by the time domain of the calibration channel. The signal calibrates the distance gate of the calibration channel signal. Since the frequency domain frequency shift of the signal can be equivalent to the time domain carrier shift, the time domain signal of the calibration channel is multiplied by the complex carrier factor, and then the time domain signal is transformed into the frequency domain. signal, can compensate for the distance gate error between the standard receiving channel and the calibration receiving channel; use the difference between the phase of the standard channel signal and the phase compensation factor as the phase of the calibration channel signal to calibrate the phase of the calibration channel signal, ensuring the phase difference consistency.

The embodiment of the present application provides a high-precision calibration method for FMCW radar with multiple receiving channels. When the radar wave reflector and the plane where the receiving antenna is located are separated by a first preset distance, the first echo signal of the standard receiving channel and the calibration method are obtained. Receive the second echo signal of the channel, according to the first echo signal and the second echo signal, take the quotient of the second gain and the first gain as the amplitude compensation factor, and calculate the low value of the first echo signal and the second echo signal First phase error, and preset the complex carrier factor, and then obtain the third echo signal of the standard receiving channel and the fourth echo of the calibration receiving channel when the radar wave reflector and the plane where the receiving antenna is located are separated by the second preset distance signal, calculate the second phase error according to the third echo signal and the fourth echo signal, and then calculate the phase compensation factor according to the first phase error and the second phase error through the phase compensation factor calculation formula, and multiply the amplitude compensation factor by the standard The standard signal amplitude of the receiving channel is used to calibrate the signal amplitude of the calibration channel, which can ensure the consistency of the gain; the range gate of the calibration channel signal is calibrated by multiplying the complex carrier factor by the time domain signal of the calibration channel. It can be equivalent to time-domain carrier transfer, so multiply the time-domain signal of the calibration channel by the complex carrier factor, and then convert the time-domain signal into a frequency-domain signal, which can compensate for the distance gate error between the standard receiving channel and the calibration receiving channel. ; Use the difference between the phase of the standard channel signal and the phase compensation factor as the phase of the calibration channel signal to calibrate the phase of the calibration channel signal to ensure the consistency of the phase. The method provided by the present application, by calculating the amplitude compensation factor, the complex carrier factor and the phase compensation factor, and respectively performing the amplitude calibration, the distance gate calibration and the phase calibration on the signal of the calibration channel through the amplitude compensation factor, the complex carrier factor and the phase compensation factor, ensuring that The multi-channel consistency is beneficial to improve the radar's target detection ability and angle measurement ability, and solves the lack of a method for high-precision calibration of radar multi-receiving channels to improve target detection ability and angle measurement accuracy. technical issues.

For ease of understanding, please refer to FIG. 2 and FIG. 4 , another embodiment of a high-precision calibration method for FMCW radar multiple receiving channels provided by the present application includes:

Step 201: Acquire the first echo signal of the standard receiving channel and the second echo signal of the calibration receiving channel when the radar wave reflector is at a first preset distance from the plane where the receiving antenna is located.

It should be noted that step 201 is the same as step 101, and details are not described herein again.

是FMCW信号的斜率。Step 202: Obtain the first gain of the first echo signal and the second gain of the second echo signal, use the quotient of the second gain and the first gain as an amplitude compensation factor, and perform a comparison between the first echo signal and the second echo. Fourier transform is performed on the signal to obtain the first Fourier transform signal and the second Fourier transform signal respectively, and the phase difference between the first Fourier transform signal and the second Fourier transform signal is taken as the first phase error φ ₁ , and preset the complex carrier factor e ^-j2πτkt , where τ is the time delay of the calibration receiving channel relative to the target echo of the standard receiving channel,

is the slope of the FMCW signal.

和

之后，分别对第一回波信号和第二回波信号进行傅里叶变换，得到第一傅里叶变换信号

和第二傅里叶变换信号显而易见地，接收通道B的目标信号比接收通道A的目标信号延迟了τk，接收通道B的增益是接收通道A的

倍，接收通道B的相位比接收通道A多旋转了弧度。对于两个接收通道接收到的信号进行傅里叶变换后产生的延迟τk，可以在傅里叶变换前对时域信号进行反向的复调制，即可去除频域的频移，将复调制的复载波因子设为e^-j2πτkt，那么，对接收通道B的第二回波信号乘以复载波因子e^-j2πτkt，即

进行傅里叶变换之后，可得

而对于冲击响应函数，只有在f＝Tk时才有有效值，其他位置处均为0，即两个接收通道的信号的距离门在同一个位置，因此，距离偏移得到了补偿。It should be noted that when the pulse radar is tracking air targets, it will set a range gate for a specific time period, and only the radar echoes received within this time period will be analyzed and processed, earlier or later than this The radar echo of the time period is ignored. It can be seen from the first echo signal and the second echo signal that compared with the receiving channel A, the receiving channel B has an increased delay τ, and the delay τ will cause the same test target to appear after being processed by the two receiving channels. On different range gates, and the phases are not the same, it is easy to cause inconsistent detection of the target distance between the receiving channels, and the effect of diversity reception cannot be achieved, and the azimuth angle of the target cannot be obtained through the phase information of the target signals of the two channels. In this embodiment of the present application, when the first echo signal is obtained

and

After that, Fourier transform is performed on the first echo signal and the second echo signal respectively to obtain the first Fourier transform signal

and the second Fourier transform signal Obviously, the target signal of receiving channel B is delayed by τk compared to the target signal of receiving channel A, and the gain of receiving channel B is that of receiving channel A.

times, the phase of receiving channel B is rotated more than that of receiving channel A radian. For the delay τk generated by the Fourier transform of the signals received by the two receiving channels, the complex modulation of the time domain signal can be performed inversely before the Fourier transform to remove the frequency shift in the frequency domain and convert the complex modulation The complex carrier factor of is set to e ^-j2πτkt , then, multiply the second echo signal of the receiving channel B by the complex carrier factor e ^-j2πτkt , namely

After Fourier transform, we can get

For the impulse response function, only when f=Tk has an effective value, and other positions are 0, that is, the distance gates of the signals of the two receiving channels are in the same position, so the distance offset is compensated.

Step 203: Obtain the third echo signal of the standard receiving channel and the fourth echo signal of the calibration receiving channel when the radar wave reflector is separated from the plane by a second preset distance, wherein the second preset distance is not equal to the first preset distance. set distance.

It should be noted that step 203 is the same as step 103, and details are not repeated here.

T为雷达探测目标回波的双程路径时延及在标准接收通道上的延迟总和，T₁为第一预置距离时的雷达波反射器回波的双程路径时延及在标准接收通道上的延迟总和，T₂为第二预置距离时的雷达波反射器回波的双程路径时延及在标准接收通道上的延迟总和。Step 204: Fourier transform is performed on the third echo signal and the fourth echo signal to obtain the third Fourier transform signal and the fourth Fourier transform respectively, and the third Fourier transform signal and the fourth Fourier transform are obtained. The phase difference of the Lie transform signal is taken as the second phase error φ ₂ . According to the first phase error φ ₁ and the second phase error φ ₂ , the phase compensation factor is calculated by the calculation formula of the phase compensation factor. The calculation formula of the phase compensation factor is:

T is the two-way path delay of the radar detection target echo and the sum of the delays on the standard receiving channel, T ₁ is the two-way path delay of the radar wave reflector echo at the first preset distance and the delay on the standard receiving channel. T ₂ is the sum of the two-way path delay of the radar wave reflector echo at the second preset distance and the delay sum of the standard receiving channel.

弧度，那么第一相位误差可以定义为φ₁＝2πτf_min-πkτ²-2πkT₁τ，可以得知，第一相位误差包括了固定常数部分2πτf_min-πkτ²和目标距离相关量-2πkT₁τ。再将雷达波反射器置于离接收天线平面的法线方向上不同与第一预置距离的第二预置距离处，同理可以得到第二预置距离处对应的两个接收通道的回波信号的第二相位误差φ₂＝2πτf_min-πkτ²-2πkT₂τ，联立第一相位误差和第二相位误差公式可以得到

因此可以推出相位补偿因子

目标距离的检测都是模值累积检测，所以相位误差不会导致累积性能下降，只要在同一个距离门上就能目标累积，因此，在求出目标距离的基础上，进行目标方位检测的时候，只需要对检出的目标点进行相位误差校准，而校准后得到的数据就可以用来精准对目标方位进行检测。It should be noted that, according to the description of step 202, the phase of receiving channel B is rotated more than that of receiving channel A.

radians, then the first phase error can be defined as φ ₁ =2πτf _min -πkτ ² -2πkT ₁ τ, it can be known that the first phase error includes the fixed constant part 2πτf _min -πkτ ² and the target distance correlation quantity -2πkT ₁ τ . The radar wave reflector is then placed at a second preset distance that is different from the first preset distance in the normal direction of the receiving antenna plane. Similarly, the echoes of the two receiving channels corresponding to the second preset distance can be obtained. The second phase error of the wave signal φ ₂ =2πτf _min -πkτ ² -2πkT ₂ τ, the formula of the first phase error and the second phase error can be obtained simultaneously

Therefore, the phase compensation factor can be deduced

The detection of the target distance is the cumulative detection of the modulo value, so the phase error will not lead to the degradation of the cumulative performance, and the target can be accumulated as long as it is on the same range gate. Therefore, on the basis of finding the target distance, when the target azimuth detection is performed , it is only necessary to perform phase error calibration on the detected target points, and the data obtained after calibration can be used to accurately detect the target azimuth.

Step 205: Store the amplitude compensation factor, the complex carrier factor and the phase compensation factor.

It should be noted that, in the embodiment of the present application, after obtaining the stored amplitude compensation factor, complex carrier factor and phase compensation factor, the stored amplitude compensation factor, complex carrier factor and phase compensation factor may be stored in a non-volatile storage unit.

Step 206: Multiply the amplitude compensation factor by the standard signal amplitude of the standard receiving channel to calibrate the amplitude of the calibration channel signal, multiply the complex carrier factor by the time domain signal of the calibration channel to calibrate the distance gate of the calibration channel signal, and use the standard channel signal to calibrate the distance gate of the calibration channel signal. The difference between the phase of and the phase compensation factor is used as the phase of the calibration channel signal to calibrate the phase of the calibration channel signal.

It should be noted that, step 206 is the same as step 105, and details are not repeated here.

For ease of understanding, please refer to FIG. 3, an embodiment of a high-precision calibration device for FMCW radar multiple receiving channels provided by the present application, including:

The first acquisition module 301 is configured to acquire the first echo signal of the standard receiving channel and the second echo signal of the calibration receiving channel when the radar wave reflector is at a first preset distance from the plane where the receiving antenna is located.

是FMCW信号的斜率。The second obtaining module 302 is configured to obtain the first gain of the first echo signal and the second gain of the second echo signal, and use the quotient of the second gain and the first gain as an amplitude compensation factor to obtain the first echo signal and the first phase error φ ₁ of the second echo signal, and preset the complex carrier factor e ^-j2πτkt , where τ is the time delay of the calibration receiving channel relative to the target echo of the standard receiving channel,

is the slope of the FMCW signal.

The third acquisition module 303 is configured to acquire the third echo signal of the standard receiving channel and the fourth echo signal of the calibration receiving channel when the radar wave reflector is at a second preset distance from the plane, wherein the second preset distance Not equal to the first preset distance.

The fourth obtaining module 304 is configured to obtain the second phase error φ 2 between the third echo signal and the fourth echo signal, and calculate the second phase error φ ₂ by the phase compensation factor calculation formula according to the first phase error φ ₁ and the second phase error φ ₂ The phase compensation factor is obtained, and the calculation formula of the phase compensation factor is: T is the two-way path delay of the radar detection target echo and the sum of the delays on the standard receiving channel, T ₁ is the two-way path delay of the radar wave reflector echo at the first preset distance and the delay on the standard receiving channel. T ₂ is the sum of the two-way path delay of the radar wave reflector echo at the second preset distance and the delay sum of the standard receiving channel.

The calibration module 305 is used for multiplying the amplitude compensation factor by the standard signal amplitude of the standard receiving channel to calibrate the signal amplitude of the calibration channel, multiplying the complex carrier factor by the time domain signal of the calibration channel to calibrate the distance gate of the calibration channel signal, The difference between the phase of the standard channel signal and the phase compensation factor is used as the phase of the calibration channel signal to calibrate the phase of the calibration channel signal.

Further, the device also includes:

The storage module 306 is used for storing the amplitude compensation factor, the complex carrier factor and the phase compensation factor.

Further, the second obtaining module 302 is specifically used for:

是FMCW信号的斜率。Obtain the first gain of the first echo signal and the second gain of the second echo signal, take the quotient of the second gain and the first gain as the amplitude compensation factor, and perform the Fourier transform on the first echo signal and the second echo signal. Lie transform, respectively obtain the first Fourier transform signal and the second Fourier transform signal, take the phase difference between the first Fourier transform signal and the second Fourier transform signal as the first phase error φ ₁ , and The preset complex carrier factor e ^-j2πτkt , where τ is the time delay of the calibration receiving channel relative to the target echo of the standard receiving channel,

is the slope of the FMCW signal.

Further, the fourth obtaining module 304 is specifically used for:

T为雷达探测目标回波的双程路径时延及在标准接收通道上的延迟总和，T₁为第一预置距离时的雷达波反射器回波的双程路径时延及在标准接收通道上的延迟总和，T₂为第二预置距离时的雷达波反射器回波的双程路径时延及在标准接收通道上的延迟总和。Fourier transform is performed on the third echo signal and the fourth echo signal to obtain the third Fourier transform signal and the fourth Fourier transform respectively, and the third Fourier transform signal and the fourth Fourier transform are obtained. The phase difference of the signal is taken as the second phase error φ ₂ . According to the first phase error φ ₁ and the second phase error φ ₂ , the phase compensation factor is calculated by the calculation formula of the phase compensation factor. The calculation formula of the phase compensation factor is:

T is the two-way path delay of the radar detection target echo and the sum of the delays on the standard receiving channel, T ₁ is the two-way path delay of the radar wave reflector echo at the first preset distance and the delay on the standard receiving channel. T ₂ is the sum of the two-way path delay of the radar wave reflector echo at the second preset distance and the delay sum of the standard receiving channel.

The present application also provides an embodiment of a computer-readable storage medium, and the computer-readable storage medium provided by the embodiment of the present application is used to store program codes, and the program codes are used to execute any of the aforementioned high-level FMCW radar multi-receiving channels. Accuracy calibration method.

The present application also provides an embodiment of a computer program product including instructions. The computer program product including instructions provided by the embodiments of the present application, when run on a computer, enables the computer to execute any of the foregoing FMCW radar multiple receptions High-precision calibration method for the channel.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the device, device and unit described above may refer to the corresponding process in the foregoing method embodiments, and details are not repeated here.

The terms "first", "second", "third", "fourth", etc. (if any) in the description of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It is to be understood that the data so used may be interchanged under appropriate circumstances such that the embodiments of the application described herein can, for example, be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, apparatus, product or device comprising a series of steps or units is not necessarily limited to those expressly listed Rather, those steps or units may include the absence of other steps or units expressly listed or inherent to these processes, methods, products or devices.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus, apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or May be integrated into another device, or some features may be omitted, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above-mentioned integrated units may be implemented in the form of hardware, or may be implemented in the form of software functional units.

The integrated unit, if implemented in the form of a software functional unit and sold or used as an independent product, may be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the present application can be embodied in the form of software products in essence, or the parts that contribute to the prior art, or all or part of the technical solutions, and the computer software products are stored in a storage medium , including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage media include: U disk, mobile hard disk, read-only memory (full English name: Read-Only Memory, English abbreviation: ROM), random access memory (English full name: Random Access Memory, English abbreviation: RAM), magnetic disks Or various media such as optical discs that can store program codes.

As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand: The technical solutions described in the embodiments are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions in the embodiments of the present application.

Claims (9)

1. a high-precision calibration method of FMCW radar multiple receiving channels, is characterized in that, comprises: 101. Obtain the first echo signal of the standard receiving channel and the second echo signal of the calibration receiving channel when the radar wave reflector and the plane where the receiving antenna is located are separated by a first preset distance; 102. Obtain a first gain of the first echo signal and a second gain of the second echo signal, use the quotient of the second gain and the first gain as an amplitude compensation factor, and obtain the first gain. The first phase error Φ ₁ between the first echo signal and the second echo signal, and the complex carrier factor e ^-j2πτkt is preset, where τ is the time delay of the calibration receiving channel relative to the target echo of the standard receiving channel, is the slope of the FMCW signal; 103. Obtain the third echo signal of the standard receiving channel and the fourth echo signal of the calibration receiving channel when the radar wave reflector is at a second preset distance from the plane, wherein the first echo signal is 2. The preset distance is not equal to the first preset distance; 104. Obtain the second phase error Φ ₂ between the third echo signal and the fourth echo signal, and calculate the phase compensation factor according to the first phase error Φ ₁ and the second phase error Φ ₂ . The formula calculates the phase compensation factor, and the calculation formula of the phase compensation factor is

T is the two-way path delay of the radar detection target echo and the sum of the delays on the standard receiving channel, T ₁ is the two-way path delay of the radar wave reflector echo at the first preset distance and the delay on the standard receiving channel. T ₂ is the two-way path delay of the radar wave reflector echo at the second preset distance and the delay sum of the standard receiving channel; 105. Multiply the amplitude compensation factor by the standard signal amplitude of the standard receiving channel to calibrate the signal amplitude of the calibration receiving channel, and multiply the complex carrier factor by the time domain signal of the calibration receiving channel to perform calibration on the calibration receiving channel. The distance gate of the channel signal is calibrated, and the phase of the calibrated receive channel signal is calibrated by taking the difference between the phase of the standard receive channel signal and the phase compensation factor as the phase of the calibrated receive channel signal. 2. The high-precision calibration method of FMCW radar multiple receiving channels according to claim 1, is characterized in that, before step 105 after step 104, also comprises: 106. Store the amplitude compensation factor, the complex carrier factor, and the phase compensation factor. 3. The high-precision calibration method of FMCW radar multiple receiving channels according to claim 1, is characterized in that, step 102 specifically comprises: Fourier transform is performed on the first echo signal and the second echo signal to obtain a first Fourier transform signal and a second Fourier transform signal respectively, and the first Fourier transform signal is and the phase difference of the second Fourier transform signal as the first phase error Φ ₁ . 4. The high-precision calibration method of FMCW radar multiple receiving channels according to claim 1, is characterized in that, step 104 specifically comprises: Fourier transform is performed on the third echo signal and the fourth echo signal to obtain a third Fourier transform signal and a fourth Fourier transform respectively, and the third Fourier transform signal and the fourth Fourier transform are obtained. The phase difference of the fourth Fourier transform signal is used as the second phase error Φ ₂ , and the phase compensation factor is calculated by the phase compensation factor calculation formula according to the first phase error Φ ₁ and the second phase error Φ ₂ . . 5. a high-precision calibration device of FMCW radar multiple receiving channels, is characterized in that, comprises: a first acquisition module, configured to acquire the first echo signal of the standard receiving channel and the second echo signal of the calibration receiving channel when the radar wave reflector is at a first preset distance from the plane where the receiving antenna is located; A second obtaining module, configured to obtain a first gain of the first echo signal and a second gain of the second echo signal, and use the quotient of the second gain and the first gain as an amplitude compensation factor , obtain the first phase error Φ ₁ of the first echo signal and the second echo signal, and preset the complex carrier factor e ^-j2πτkt , where τ is the target echo of the calibration receiving channel relative to the standard receiving channel time delay,

is the slope of the FMCW signal; a third acquisition module, configured to acquire the third echo signal of the standard receiving channel and the fourth echo signal of the calibration receiving channel when the radar wave reflector is at a second preset distance from the plane, Wherein, the second preset distance is not equal to the first preset distance; a fourth acquisition module, configured to acquire a second phase error Φ ₂ between the third echo signal and the fourth echo signal, and according to the first phase error Φ ₁ and the second phase error Φ ₂ , The phase compensation factor is calculated by the phase compensation factor calculation formula, and the phase compensation factor calculation formula is:

T is the two-way path delay of the radar detection target echo and the sum of the delays on the standard receiving channel, T ₁ is the two-way path delay of the radar wave reflector echo at the first preset distance and the delay on the standard receiving channel. T ₂ is the two-way path delay of the radar wave reflector echo at the second preset distance and the delay sum of the standard receiving channel; The calibration module is used for multiplying the amplitude compensation factor by the standard signal amplitude of the standard receiving channel to calibrate the signal amplitude of the calibration receiving channel, and multiplying the complex carrier factor by the time domain signal of the calibration receiving channel to calibrate the signal amplitude of the calibration receiving channel. The range gate for calibrating the receiving channel signal is calibrated, and the phase of the calibration receiving channel signal is calibrated using the difference between the phase of the standard receiving channel signal and the phase compensation factor as the phase of the calibration receiving channel signal. 6. The high-precision calibration device of FMCW radar multiple receiving channels according to claim 5, is characterized in that, described device also comprises: A storage module, configured to store the amplitude compensation factor, the complex carrier factor and the phase compensation factor. 7. The high-precision calibration device of FMCW radar multiple receiving channels according to claim 5, wherein the second acquisition module is specifically used for: Fourier transform is performed on the first echo signal and the second echo signal to obtain a first Fourier transform signal and a second Fourier transform signal respectively, and the first Fourier transform signal is and the phase difference of the second Fourier transform signal as the first phase error Φ ₁ . 8. The high-precision calibration device of FMCW radar multiple receiving channels according to claim 5, wherein the fourth acquisition module is specifically used for: Fourier transform is performed on the third echo signal and the fourth echo signal to obtain a third Fourier transform signal and a fourth Fourier transform respectively, and the third Fourier transform signal and the fourth Fourier transform are obtained. The phase difference of the fourth Fourier transform signal is used as the second phase error Φ ₂ , and the phase compensation factor is calculated by the phase compensation factor calculation formula according to the first phase error Φ ₁ and the second phase error Φ ₂ . . 9. A computer-readable storage medium, characterized in that, the computer-readable storage medium is used for storing program codes, and the program codes are used for executing the multi-receiving channel of the radar according to any one of claims 1-4. High precision calibration method.

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