A MTI processing method for multi-channel radar

Abstract

The present invention relates to a multi-channel radar MTI processing method, which is composed of a multi-channel time domain accumulation module, a delay cancellation filtering module, and a recursive filtering module, and includes the following steps: after receiving a time domain signal, simultaneously performing time domain accumulation processing and recursive filtering processing of a moving target, and after waiting for the accumulator to complete the required number of accumulation groups, performing delay cancellation filtering processing on the accumulated signal, thereby obtaining the processing results of the moving target and the processing results of the micro-moving target. The MTI processing method described in the present invention designs multi-channel data joint processing to improve data utilization; distinguishes between moving and micro-moving targets to effectively improve the ability to extract different targets; and is simple and fast to implement, saving radar processing unit resource overhead.

Description

Technical Field

[0001] The present invention relates to the field of radar detection technology, and in particular to a multi-channel radar MTI processing method. Background Art

[0002] Radar detects information related to target signals through radio transmission. The relevant parameters of these target signals are obtained through the reflection of electromagnetic waves on the target signals. From the perspective of the characteristics of moving target signals and fixed clutter, the size of the speed value and the difference in direction are the basis for distinguishing moving target signals from fixed clutter. This method of distinguishing the characteristics of moving target signals and fixed clutter uses the Doppler difference between the target echo signal and the fixed clutter. The Doppler difference is caused by the different speeds of the two relative to the radar. What we ultimately need to do is to suppress the clutter and extract the parameters of the target signal.

[0003] Conventional radar moving target indication (MTI) processing uses a delay line canceller to suppress the impact of clutter on the target signal, so that the measurement obtains fuzzy Doppler velocity and clear range. However, in practical applications, considering the complexity of the radar working environment, factors such as thunderstorms, fog, waves, fixed objects, etc. will produce certain interference to affect the normal operation of the radar. These interferences mainly include static clutter and dynamic clutter. The clutter signals in pieces drown the echo signals of the moving targets, making it very difficult to observe the targets. Especially in the presence of strong clutter, the target signal is easily drowned by the strong clutter, and the target signal cannot be extracted at this time. In addition, for the complex environment with strong interference from ground clutter, simple delay cancellation cannot effectively remove the interference clutter. For the relatively clean detection environment, delay cancellation cannot well detect the micro-moving targets. Common radar MTI processing cannot take into account the filtering of moving targets and micro-moving targets at the same time, and is usually a split processing, which makes the processing efficiency low and greatly increases the resource overhead of the signal processing unit. Summary of the invention

[0004] To this end, the technical problem to be solved by the present invention is to overcome the problem that conventional radars cannot completely and simultaneously perform MTI filtering processing on moving targets and micro-moving targets when facing a complex noise environment and a weak target echo signal. To address this problem, this patent provides a multi-channel radar MTI processing method for low, small and slow targets, which solves the problem that existing radars cannot simultaneously perform multi-beam processing on the filtering of moving and static targets.

[0005] In order to solve the above technical problems, the present invention provides a multi-channel radar MTI processing method, which is composed of three processing units: multi-channel time domain accumulation processing, moving target iterative cancellation processing, and micro-motion target secondary cancellation processing, and includes the following steps:

[0006] Step S1: applying for a data address for storing the time domain signal received by the signal processing unit from the radar front end after beamforming, and clearing the accumulative counter;

[0007] Step S2: after receiving the first group and subsequent signal data, one path stores the data into the accumulated data set, and adds 1 to the counter, and one path of the data enters the recursive filtering module of the moving target for processing;

[0008] Step S3: When the counter is greater than a specified value, the accumulated data is sent to the delay cancellation filter module of the micro-motion target for processing, and the counter is set to 0;

[0009] Step S4: Repeat the above steps S2 to S3 in a loop until the system sends a stop command.

[0010] In one embodiment of the present invention, the multi-channel time domain signal is a time domain data obtained by beamforming after multi-channel AD sampling at the radar front end and transmitted to the radar back end for signal processing.

[0011] In one embodiment of the present invention, the multi-channel time domain signals are non-coherently accumulated, and only the time domain data are accumulated.

[0012] In one embodiment of the present invention, radar moving target extraction adopts a multiple iteration cancellation processing method with feedback coefficients, which can effectively filter out environmental noise and improve the signal-to-noise ratio of the moving target.

[0013] In one embodiment of the present invention, the recursive filtering module in step S2 uses a delay canceller with a feedback loop. The advantage of recursive filtering is that through the feedback loop, we can change the frequency response shape of the filter. The selection range of the K value is 0 to 1. The K value selected in this patent is 0.85. The output signal is as follows:

[0014] y(t)=x(t)-(1-K)w(t);

[0015] v(t)=y(t)+w(t);

[0016] w(t)=v(tT).

[0017] In one embodiment of the present invention, the filter cancellation module in step S3 adopts a single delay canceller, and the delay T is equal to the radar PRI (1 / f r ), n is the number of accumulation groups in the multi-channel time domain accumulation module, and the output signal is as follows:

[0018] y(t)=x(t)-x(t-nT).

[0019] In one embodiment of the present invention, the specified value in step S3 is the minimum number of accumulations from which valid targets can be extracted after the data after multiple accumulations are processed by MTI.

[0020] The above technical solution of the present invention has the following advantages over the prior art: the MTI processing method described in the present invention designs multi-channel data joint processing to improve data utilization; it distinguishes between moving and micro-moving targets and effectively improves the ability to extract different targets; and it is simple and fast to implement, saving radar processing unit resource overhead. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0022] Figure 1 It is a design block diagram of the multi-channel radar MTI processing method of the present invention.

[0023] Figure 2-1 It is a design block diagram of the multi-channel time domain accumulation module described in the present invention.

[0024] Figure 2-2 It is a design block diagram of the delay cancellation filter processing module described in the present invention.

[0025] Figure 2-3 It is a design block diagram of the recursive filtering processing module described in the present invention.

[0026] Figure 3 This is a waveform diagram after the MTI of the present invention processes the moving target.

[0027] Figure 4 This is a waveform diagram after the MTI of the present invention processes the micro-motion target. DETAILED DESCRIPTION

[0028] like Figure 1 As shown, this embodiment provides a multi-channel radar MTI processing method, which is composed of three processing units: multi-channel time domain accumulation processing, moving target iterative cancellation processing, and micro-movement target secondary cancellation processing, which correspond to the three processing units of multi-channel time domain accumulation module, delay cancellation filtering module, and recursive filtering module, respectively. Figure 2-1 As shown, the multi-channel time domain signal is the time domain data transmitted to the radar back end for signal processing after the multi-channel AD sampling of the radar front end is processed by beamforming, and the signal is non-coherently accumulated, and only the time domain data is accumulated. It also includes the following steps:

[0029] Step S1: applying for a data address for storing the time domain signal received by the signal processing unit from the radar front end after beamforming, and clearing the accumulative counter;

[0030] Step S2: after receiving the first group and subsequent signal data, one path stores the data into the accumulated data set, and adds 1 to the counter, and one path of the data enters the recursive filtering module of the moving target for processing;

[0031] Step S3: When the counter is greater than a certain specified value (the specified value is the minimum number of accumulated data that can extract a valid target after MTI processing), the accumulated data is sent to the delay cancellation filter module of the micro-motion target for processing, and the counter is set to 0;

[0032] Step S4: Repeat the above steps S2 to S3 in a loop until the system sends a stop command.

[0033] like Figure 2-2 As shown, the filter module uses a single delay canceller, and the delay T is equal to the radar's PRI (1 / f r ), n is the number of accumulation groups in the multi-channel time domain accumulation module, and the output signal is as follows:

[0034] y(t)=x(t)-x(t-nT).

[0035] like Figure 2-3 As shown, the recursive filtering module uses a delay canceller with a feedback loop. The advantage of recursive filtering is that through the feedback loop, we can change the frequency response shape of the filter. The selection range of the K value is 0 to 1. The K value selected in this patent is 0.85. The output signal is as follows:

[0036] y(t)=x(t)-(1-K)w(t);

[0037] v(t)=y(t)+w(t);

[0038] w(t)=v(tT).

[0039] The use of multiple iterative cancellation with feedback coefficients can effectively filter out environmental noise and improve the signal-to-noise ratio of moving targets. At the same time, simple quadratic cancellation in the time domain is simple to process, fast in time, and can effectively extract the distance information of micro-moving targets.

[0040] In summary, after MTI processing, the moving target and the micro-moving target complete the moving target display processing respectively.

[0041] In order to verify the feasibility of this design method, with the help of the existing hardware platform, the design verification scenario is as follows:

[0042] 1) Target A is located 4m away from the radar and stands still;

[0043] 2) Target B is located 16m from the radar and is standing still;

[0044] 3) The radar adopts the MTI processing method of this design scheme and checks the data waveform of the MTI processing result.

[0045] The processing effect is shown in the figure Figure 3 , Figure 4 shown.

[0046] pass Figure 3 and Figure 4 It can be seen that after the feedback filtering, the moving target B can be intuitively displayed in Figure 3 In the waveform, the signal at the stationary target A is weak and almost submerged in the clutter, making it impossible to detect. After accumulation, delay cancellation and filtering, the stationary target A can be detected. Figure 4 The moving target B can also be observed in the waveform, but since the signal of target B is unstable, only the information of target A, whose signal is relatively stable, is read as the filtered signal output.

[0047] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A multi-channel radar MTI processing method, the processing method is composed of a multi-channel time domain accumulation module, a delay cancellation filtering module, and a recursive filtering module, characterized in that: The steps include: Step S1: applying for a data address for storing the time domain signal received by the signal processing unit from the radar front end after beamforming, and clearing the accumulative counter; Step S2: after receiving the first group and subsequent signal data, one channel of data is stored in the accumulated data set, and the counter is incremented by 1, and one channel of data enters the recursive filtering module of the moving target for processing; Step S3: When the counter is greater than a specified value, the accumulated data is sent to the delay cancellation filter module of the micro-motion target for processing, and the counter is set to 0; Step S4: Repeat the above steps S2 to S3 in a loop until the system sends a stop command.

2. The MTI processing method according to claim 1, characterized in that: The multi-channel time domain signal is the time domain data obtained by beamforming after multi-channel AD sampling at the radar front end and transmitted to the radar back end for signal processing.

3. The MTI processing method according to claim 2, characterized in that: The multi-channel time domain signals are non-coherently accumulated, and only the time domain data are accumulated.

4. The MTI processing method according to claim 1, characterized in that: The recursive filtering module in step S2 uses a delay canceller with a feedback loop. The advantage of recursive filtering is that through the feedback loop, we can change the frequency response shape of the filter. The selection range of the K value is 0 to 1. The K value selected in this patent is 0.

85. The output signal is as follows: y(t)=x(t)-(1-K)w(t); v(t)=y(t)+w(t); w(t)=v(tT).

5. The MTI processing method according to claim 1, characterized in that: The cancellation filter module in step S3 uses a single delay canceller, and the delay T is equal to the radar's PRI (1 / f r ), n is the number of accumulation groups in the multi-channel time domain accumulation module, and the output signal is as follows: y(t)=x(t)-x(t-nT).

6. The MTI processing method according to claim 1, characterized in that: The specified value n in step S3 is the minimum number of accumulations from which valid targets can be extracted after the data after multiple accumulations are processed by MTI.

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