阅读说明：本技术 基于mimo雷达的目标检测方法、装置、电子设备及存储介质 (Target detection method and device based on MIMO radar, electronic equipment and storage medium ) 是由 彭佳 李仕贤 谭俊杰 钟仁海 张燎 于 2021-09-03 设计创作，主要内容包括：本发明提供一种基于MIMO雷达的目标检测方法、装置、电子设备及存储介质,属于雷达信号处理技术领域,所述方法包括：获取所述MIMO雷达接收到的多个对象的原始编码信号；基于所述原始编码信号重构出所述多个对象中的一部分对象的估计编码信号；将所述重构出的一部分对象的估计编码信号从所述原始编码信号中剔除,得到目标对象的多普勒频率信号。本发明可防止因强目标的多普勒杂散覆盖弱目标的回波信号而导致弱目标漏检的情况。(The invention provides a target detection method and device based on an MIMO radar, electronic equipment and a storage medium, belonging to the technical field of radar signal processing, wherein the method comprises the following steps: acquiring original coding signals of a plurality of objects received by the MIMO radar; reconstructing an estimated encoded signal of a portion of the objects based on the original encoded signal; and removing the reconstructed estimated code signals of a part of objects from the original code signals to obtain Doppler frequency signals of the target object. The invention can prevent the condition that the detection of the weak target is missed because the Doppler stray of the strong target covers the echo signal of the weak target.)

1. A target detection method based on MIMO radar is characterized by comprising the following steps:

acquiring original coding signals of a plurality of objects received by the MIMO radar;

reconstructing an estimated encoded signal of a portion of the objects based on the original encoded signal;

and removing the reconstructed estimated coding signals of a part of objects from the original coding signals to obtain original coding signals of the target objects.

2. The method of claim 1, wherein the step of obtaining the original encoded signals of the plurality of objects received by the MIMO radar comprises:

sampling original coding signals in each linear frequency modulation pulse of the MIMO radar to obtain sample data;

generating a data matrix based on the sample data；

For the data matrixEach column of (a) is made to be of length（) To obtain a data matrix；

Wherein the content of the first and second substances,indicating the length of the sample data and N the number of chirps.

3. The method of claim 2, wherein reconstructing an estimated code signal of a portion of the plurality of objects based on the original code signal comprises:

from the data matrixStarting with the first row of the data matrixAs the current row, each row in the previous part of rows performs the following steps 1-8:

step 1, for the data matrixDecoding the Doppler data of the current row to obtain a decoding matrix；

Step 2, decoding the matrixIs made of data of all columns of length Fourier transform of the Doppler spectrum data matrix to obtain the Doppler spectrum data matrix；

Step 3, aiming at the Doppler frequency spectrum data matrixThe square of the amplitude is calculated and accumulated according to the transmitting channel to obtain a data matrix；

Step 4, obtaining the data matrixMaximum value ofAnd its positionAnd evaluating said data matrixAverage value of (2)；

Step 5, according to the positionEstimating the normalized frequency of the object to which it correspondsAnd generating a unit signal from the normalized frequencyWherein=/；

Step 6, according to the positionFrom said Doppler frequency data matrixExtracting channel data of corresponding position to obtain amplitude coefficient of each emission channel of object corresponding to the position；

Step 7, utilizing the amplitude coefficient of each transmitting channelGenerating a spurious signal；

Step 8, according to the stray signalAnd the unit signalReconstructing an estimated encoded signal of the object corresponding to the locationWherein。

4. The method of claim 3, wherein the step of removing the reconstructed estimated encoded signals of the part of the objects from the original encoded signals to obtain original encoded signals of the target objects comprises:

after each execution of the steps 1-8, the following step 9 is executed:

step 9, encoding the estimated code signalFrom the data matrixIs removed from the doppler data of the current line.

5. The method of claim 4, wherein reconstructing an estimated code signal of a portion of the plurality of objects based on the original code signal further comprises:

setting a threshold of the number of loops before executing the step 1 for the first timeAnd counting cyclesThe initialized value is 0, then after each execution of said step 4 the following operations are performed:

if the maximum value obtained in the step 4 is the maximum valueSatisfies the conditionsIf yes, jumping out of the cycle and finishing the whole reconstruction and elimination operation;

if the maximum value obtained in the step 4 is the maximum valueSatisfies the conditionsThen give an orderAnd if newly assignedIf yes, jumping out of the loop and finishing the whole reconstruction and elimination operation, otherwise, continuing to execute the subsequent step 5;

wherein, T is a preset detection threshold value.

6. According to any one of claims 3 to 5The MIMO radar-based target detection method, wherein the unit signal in step 5Expressed as:

；

wherein the content of the first and second substances,the sign of the imaginary number is represented,representing a normalized frequency.

7. The MIMO radar-based target detection method of claim 6, wherein the amplitude coefficient in step 6Expressed as:

；

；

wherein M is the number of transmission channels, N is the number of Doppler channels,。

8. the MIMO radar-based target detection method of claim 7, wherein the spurious signals in step 7Expressed as:

；

wherein C represents a matrix of randomly coded coefficients, i.e.

。

9. An object detection device based on a MIMO radar, comprising:

the data acquisition module is used for acquiring original coding signals of a plurality of objects received by the MIMO radar;

a reconstruction module for reconstructing an estimated encoded signal of a portion of the objects based on the original encoded signal;

and the detection module is used for removing the reconstructed estimated coding signals of a part of objects from the original coding signals to obtain the original coding signals of the target objects.

10. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor, when executing the program, implements the steps of the MIMO radar based object detection method according to any one of claims 1 to 8.

11. A non-transitory computer readable storage medium having stored thereon a computer program, which when executed by a processor implements the steps of the MIMO radar based target detection method of any one of claims 1 to 8.

Technical Field

The invention relates to the technical field of radar signal processing, in particular to a target detection method and device based on an MIMO radar, electronic equipment and a storage medium.

Background

The MIMO (Multiple input Multiple output) radar is a radar with a new system, which is generated by introducing Multiple input and Multiple output technologies in a wireless communication system into the field of radar and combining the technologies with a digital array technology.

Based on the phase random coding, the MIMO radar transmits a plurality of signals which are not correlated with each other at a transmitting end. At the receiving end, the echoes of multiple transmitted signals are summed together. During decoding, one code can only solve the echo signal of one transmitting channel, and the echo signals of other transmitting channels are covered on the decoded echo signal in a stray mode. The spurious signal is a signal which interferes with the detection of the target in the echo signal. The strength of the stray signal is related to the reflection strength of the echo signal of the target, and when a plurality of targets are in the same range cell, the doppler stray of a strong target may cover the echo signal of a weak target, thereby causing the detection omission of the weak target. The strong target and the weak target refer to the power intensity of the echo signal of the target and can be measured by a signal-to-noise ratio. In addition, when the MIMO radar is applied to an environment with dense targets, targets with different speeds at the same distance are likely to appear, and therefore, doppler spurious signals of strong targets are likely to appear to cover echo signals of weak targets.

Disclosure of Invention

The invention provides a target detection method, a target detection device and electronic equipment based on an MIMO radar, which are used for solving the problem that in the prior art, Doppler stray of a strong target covers an echo signal of a weak target, so that the detection omission of the weak target is caused, and the strong target stray is removed from an original coding signal and the weak target is displayed.

The invention provides a target detection method based on an MIMO radar, which comprises the following steps:

acquiring original coding signals of a plurality of objects received by the MIMO radar;

reconstructing an estimated encoded signal of a portion of the objects based on the original encoded signal;

and removing the reconstructed estimated coding signals of a part of objects from the original coding signals to obtain original coding signals of the target objects.

According to the target detection method based on the MIMO radar of the present invention, the step of acquiring the original coded signals of the plurality of objects received by the MIMO radar includes:

sampling original coding signals in each linear frequency modulation pulse of the MIMO radar to obtain sample data;

generating a data matrix based on the sample data；

For the data matrixEach column of (a) is made to be of length（) To obtain a data matrix；

Wherein the content of the first and second substances,indicating the length of the sample data and N the number of chirps.

According to the target detection method based on the MIMO radar of the present invention, the step of reconstructing an estimated encoded signal of a part of the objects based on the original encoded signal comprises:

from the data matrixStarting with the first row of the data matrixAs the current row, each row in the previous part of rows performs the following steps 1-9:

step 1, for the data matrixDecoding the Doppler data of the current row to obtain a decoding matrix；

Step 2, decoding the matrixIs made of data of all columns of length Fourier transform of the Doppler spectrum data matrix to obtain the Doppler spectrum data matrix；

Step 3, aiming at the Doppler frequency spectrum data matrixThe square of the amplitude is calculated and accumulated according to the transmitting channel to obtain a data matrix；

Step 4, obtaining the data matrixMaximum value ofAnd its positionAnd evaluating said data matrixAverage value of (2)；

Step 5, according to the positionEstimating the normalized frequency of the object to which it correspondsAnd generating a unit signal from the normalized frequencyWherein=/；

Step 6, according to the positionFrom said Doppler frequency data matrixExtracting channel data of corresponding position to obtain amplitude coefficient of each emission channel of object corresponding to the position；

Step 7, utilizing the amplitude coefficient of each transmitting channelGenerating a spurious signal；

Step 8, according to the stray signalAnd the unit signalReconstructing an estimated encoded signal of the object corresponding to the locationWherein。

According to the target detection method based on the MIMO radar of the present invention, the step of removing the reconstructed estimated encoded signal of a part of the objects from the original encoded signal to obtain the original encoded signal of the target object includes:

after each execution of the steps 1-8, the following step 9 is executed:

step 9, encoding the estimated code signalFrom the data matrixIs removed from the doppler data of the current line.

According to the target detection method based on the MIMO radar of the present invention, the step of reconstructing an estimated encoded signal of a part of the objects based on the original encoded signal further includes:

setting a threshold of the number of loops before executing the step 1 for the first timeAnd counting cyclesThe initialized value is 0, then after each execution of said step 4 the following operations are performed:

if the maximum value obtained in the step 4 is the maximum valueSatisfies the conditionsIf yes, jumping out of the cycle and finishing the whole reconstruction and elimination operation;

if the maximum value obtained in the step 4 is the maximum valueSatisfies the conditionsThen give an orderAnd if newly assignedIf yes, jumping out of the loop and finishing the whole reconstruction and elimination operation, otherwise, continuing to execute the subsequent step 5;

wherein, T is a preset detection threshold value.

According to the target detection method based on the MIMO radar, the unit signal in the step 5Expressed as:

；

wherein the content of the first and second substances,the sign of the imaginary number is represented,representing a normalized frequency.

According to the target detection method based on the MIMO radar, the amplitude coefficient in the step 6Expressed as:

；

；

wherein M is the number of transmission channels, N is the number of Doppler channels,。

according to the target detection method based on the MIMO radar, the spurious signal in the step 7Expressed as:

；

wherein C represents a matrix of randomly coded coefficients, i.e.

。

The invention also provides a target detection device based on the MIMO radar, which comprises:

the data acquisition module is used for acquiring original coding signals of a plurality of objects received by the MIMO radar;

a reconstruction module for reconstructing an estimated encoded signal of a portion of the objects based on the original encoded signal;

and the detection module is used for removing the reconstructed estimated coding signals of a part of objects from the original coding signals to obtain the original coding signals of the target objects.

The present invention also provides an electronic device, comprising a memory, a processor and a computer program stored on the memory and operable on the processor, wherein the processor implements the steps of the MIMO radar-based target detection method according to any one of the above-mentioned embodiments when executing the program.

The present invention also provides a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the steps of the MIMO radar based target detection method as any one of the above.

According to the target detection method, the device, the electronic equipment and the storage medium based on the MIMO radar, the frequency information and the amplitude information of the target are estimated, and the estimated encoding signal of the target can be reconstructed by combining the known phase encoding; then, a preset algorithm (such as a CLEAN algorithm) is used for removing the reconstructed estimated coding signal of a certain target from the original coding signal one by one, and finally the original coding signal of the target object (such as a weak target) is obtained, so that the original coding signal of the weak target is prevented from being missed.

Drawings

In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a schematic flow chart of a target detection method based on MIMO radar according to the present invention;

FIG. 2 is a schematic flow chart of the present invention for obtaining an original encoded signal;

FIG. 3 is a schematic flow chart of the present invention for reconstructing an estimated encoded signal;

FIG. 4 is a schematic flow chart of the present invention for removing the estimated encoded signal;

FIG. 5 is a schematic flow chart diagram of one embodiment of the present invention;

FIGS. 6-8 are schematic diagrams of simulation results provided by the present invention;

fig. 9 is a schematic structural diagram of a target detection device based on MIMO radar according to the present invention;

fig. 10 is a schematic structural diagram of an electronic device provided by the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terms "first," "second," and the like in the description and in the claims, and in the drawings described above, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be practiced otherwise than as specifically illustrated or described herein.

The target detection method, the target detection device, the electronic equipment and the storage medium based on the MIMO radar are used for solving the problem that Doppler stray of a strong target covers an echo signal of a weak target in the prior art, so that the detection omission of the weak target is caused.

By estimating the frequency information and the amplitude information of the target and combining the known phase encoding, an estimated encoding signal of the target can be reconstructed; then, a preset algorithm (such as a CLEAN algorithm) is utilized to sequentially remove the reconstructed estimated coded signal of a certain target from the original coded signal, and finally the original coded signal of the target object (such as a weak target) is obtained, so that strong target spurs are removed from the original coded signal, and the weak target is displayed.

The following describes a target detection method, an apparatus and an electronic device based on MIMO radar according to the present invention with reference to fig. 1 to 10.

Fig. 1 is a schematic flow chart of a target detection method based on MIMO radar according to the present invention, as shown in fig. 1. A target detection method based on MIMO radar comprises the following steps:

step 101, acquiring original coded signals of a plurality of objects received by the MIMO radar.

Alternatively, the original coded signal may be obtained from each Chirp (Chirp) at the radar receiving end. The original coding signals are original coding signals of a plurality of objects, and the plurality of objects comprise original coding signals of strong targets and original coding signals of weak targets in relative terms, namely the original coding signals comprise at least one original coding signal above one object.

Step 102, reconstructing an estimated encoded signal of a part of the objects based on the original encoded signal.

Optionally, the frequency information and the amplitude information of a plurality of targets in the original encoded signal may be estimated based on preset conditions, and the estimated encoded signal of a part of the plurality of objects may be reconstructed by combining preset phase encoding information.

Optionally, the preset condition is used to limit the estimation of the frequency information and the amplitude information of all or part of the objects in the original encoded signal. Then, based on the estimated frequency information and amplitude information of the object, and combining with the preset phase encoding information (i.e. the known phase encoding information), the estimated encoding information of a part of the objects in the plurality of objects can be reconstructed.

Step 103, removing the reconstructed estimated encoding signals of a part of objects from the original encoding signals to obtain original encoding signals of the target objects.

Exemplarily, the following steps are carried out:

original coded signal:

the original coded signal of object 1, the original coded signal of object 2, the original coded signal of object 3, …, the original coded signals of these objects constituting a set of original coded signals of a plurality of objects.

The method is divided according to the order of strength and weakness, and the sequence is assumed as follows: object 1> object 2> object 3> … > target object n (or weak target).

And (3) according to the strength sequence, reconstructing an estimated coding signal:

the estimated encoded signal of object 1, the estimated encoded signal of object 2, the estimated encoded signal of object 3, …, the estimated encoded signal of object n-1.

And successively removing the reconstructed estimated coded signal of the object from the original coded signal through a preset algorithm (such as a CLEAN algorithm), namely removing a stray signal generated by a strong target (such as successively removing an object 1, an object 2, an object 3, … and an object n-1) from the original coded signal until the original coded signal of the target object n is presented.

The CLEAN algorithm in the field of radar signal processing is a signal processing method capable of accurately removing single-frequency components. In the field of radar signal processing, the existing clutter suppression method mainly comprises moving target display (MTI), Generalized Matched Filter (GMF) and CLEAN algorithm.

Therefore, the reconstructed estimated coding signals corresponding to the targets are removed from the original coding signals successively by using a preset algorithm (such as a CLEAN algorithm), so that the original coding signals of the targets to be detected (such as weak targets) are obtained, and the problem of missing detection of the weak targets can be effectively prevented.

The steps 101 to 103 will be described in detail with reference to the accompanying drawings.

Fig. 2 is a schematic flow chart of acquiring an original encoded signal according to the present invention, as shown in fig. 2. In the above step 101, the step of acquiring original coded signals of a plurality of objects received by the MIMO radar includes:

step 201, sampling an original coding signal in each chirp of the MIMO radar to obtain sample data.

The MIMO (Multiple input Multiple output) radar is a radar with a new system, which is generated by introducing Multiple input and Multiple output technologies in a wireless communication system into the field of radar and combining the technologies with a digital array technology. Therefore, the MIMO radar can classify multiple signals in time domain, space domain or polarization domain, and has the advantages of higher processing dimension, more full utilization of transceiving aperture and higher angular resolution.

Optionally, ADC (Analog-to-digital converter) data sampling is performed on the original encoding signal of each chirp of the MIMO radar to obtain sample data, and the sample data is stored.

Wherein the sample data has a length ofThe number of one Chirp (Chirp) is。

It should be noted that the reference symbol N in the present invention indicates the number of chirps (i.e., the Chirp number), the number of doppler channels, and the length of doppler data, respectively, and they are the same in terms of their physical meanings and are only expressed differently in different usage scenarios, but this is not intended to limit the present invention.

Step 202, generating a data matrix based on the sample data。

Step 203, for the data matrixEach column of (a) is made to be of length（) To obtain a data matrix。

Target echoes of the random coding MIMO radar at different distances (corresponding to different echo frequencies) are superposed together in the time domain, so that the target echoes are difficult to estimate in the time domain directly. Therefore, the signal needs to be converted to the frequency domain by fourier transform (FFT) for processing. Therefore, for the data matrixEach column of is made to be of length（) Obtaining a one-dimensional FFT processing result。

Fig. 3 is a schematic flow chart of reconstructing an estimated encoded signal according to the present invention, as shown in fig. 3. In the aforementioned step 102, the step of reconstructing an estimated encoded signal of a part of the objects based on the original encoded signal includes:

from the data matrixStarting with the first row of the data matrixEach of the previous portion of columns as the current column performs the following steps 301-308:

step 301, for the data matrix in the above step 203Current row (e.g., current row) ofFirst, theLine) of doppler dataDecoding to obtain a decoding matrix。

When the phase random encoding MIMO radar is applied to an environment with dense targets, targets with different speeds in the same distance are easy to appear, and the situation that the Doppler stray of a strong target covers the echo of a weak target is easy to appear.

Due to the data matrixLine data ofRepresenting range units, different range units corresponding to different echo frequencies, the same range unit including targets of different speeds, i.e. the targets of different speeds include strong and weak targets in relative terms, thus requiring to apply the data matrixThe doppler data for each row is decoded.

Step 301 above illustrates that the first row (i.e., row) is first aligned) Doppler data ofAnd decoding is carried out.

Assume that the coding coefficient matrix C is:

；

wherein M is the number of transmitting channels. Suppose thatCode element ofAnd is andobeying two dimensions

Normally distributed, with the number of quantization bits of the phase being，Representing an imaginary symbol. Then there are:

。

the decoded data vector is then:

。

step 302, decoding the matrixIs made of data of all columns of length Fourier Transform (FFT) of the Doppler spectrum data matrix to obtain the Doppler spectrum data matrix。

Step 303, for the Doppler spectrum data matrixThe square of the amplitude is calculated and accumulated according to the transmitting channel to obtain a data matrix. Expressed by the formula:

；

the above formula shows that all elements of the matrix S are squared in absolute value and accumulated in columns to obtain a vector E, and E represents a Doppler energy spectrum non-coherent accumulation result.

In this step, Doppler spectrum data is subjected toNon-coherent accumulation is performed according to the transmitting channel, so that the gain can be improved.

Step 304, obtaining the data matrixMaximum value ofAnd its spectral peak positionAnd evaluating said data matrixAverage value of (2)。

In this step, the peak position of the spectrum is obtainedI.e., the location of the maximum of the doppler spectrum, for use in calculating the doppler frequency. Mean value ofIn order to calculate the average power of the frequency spectrum, the peak-to-average ratio can be used as a parameter to set a preset detection threshold value T.

305, according to the spectrum peak positionEstimating the normalized frequency of the object to which it corresponds(=/) And generating a unit signal from the normalized frequency. Expressed by the formula:

。

step 306, according to the positionFrom said Doppler frequency data matrixExtracting channel data of corresponding position to obtain amplitude coefficient of each emission channel of object corresponding to the position。

Wherein the content of the first and second substances,expressed by the formula:

。

step 307, using the amplitude coefficient of each transmitting channelGenerating a spurious signal. Expressed by the formula:

；

wherein C represents a matrix of randomly coded coefficients, i.e.

。

Step 308, according to the spurious signalAnd the unit signalReconstructing an estimated encoded signal of the object corresponding to the locationWherein。

The reconstruction can be realized through the steps 301 to 308The estimated code signal of the strongest object of the row.

Fig. 4 is a schematic flow chart of the present invention for removing the estimated encoded signal, as shown in fig. 4. In step 103, the step of removing the reconstructed estimated encoded signal of the part of the objects from the original encoded signal to obtain an original encoded signal of the target object includes:

step 401, estimating the encoded signal in the step 308From the Doppler data in step 301Medium culling, expressed as:。

step 402, returning to the above step 301 to execute the reconstructionEstimating coding information of the strongest target of the row until the data matrix is traversed according to the steps 301 to 401The doppler data of all rows of the target object, the original coded signal of the target object is obtained.

It should be noted that fig. 3 and 4 describe the reconstructionAn example of estimating and eliminating the encoding signal of the strongest target in the row, if the loop traversal is needed, a preset condition needs to be set, and the step of setting the preset condition is as follows:

setting the preset condition, i.e. setting the loop of the CLEAN algorithm, before the first execution of step 301 aboveLoop times thresholdSetting and counting cyclesThe initialized value is 0, and then after each execution of said step 304 the following operations are performed:

condition 1: if the maximum value obtained in this step 304 is not zeroSatisfies the conditionsAnd jumping out of the CLEAN loop and finishing the whole reconstruction and elimination operation.

Condition 2: if the maximum value obtained in this step 304 is not zeroSatisfies the conditionsThen, thenIf newly assignedThen jumping out of CLEAN circulation and finishing the whole reconstruction and elimination operation; if it isThen the following step 305 is continued.

That is, before the above step 301 is executed circularly, the clear loop frequency is set, and after the above step 304, the determination is made according to the above conditions 1 and 2, and the steps 301 to 401 are executed circularly according to the determination result.

The MIMO radar-based target detection method according to the present invention is described below with an embodiment.

Fig. 5 is a schematic flow chart of an embodiment of the present invention, as shown in fig. 5.

First, a doppler frequency signal is defined, expressed by the equation:

；

wherein the content of the first and second substances,in order to be the length of the doppler data,is the doppler FFT length.The frequency is normalized for the signal doppler.

Then, an encoded signal is defined, represented by the equation:

；

wherein the content of the first and second substances,for randomly encoding the coefficient matrix, i.e.

M is the number of transmission channels, and N is the number of Doppler channels. It is assumed that,code element ofThe quantization bit number of the phase isThen, there are:

。

definition ofThen, based on the decoded coefficients and the encoded signal, the decoded signal can be defined as:

；

wherein the content of the first and second substances,to obtain

；

Due to the fact thatBeing randomly distributed, the above equation may thus become:

；

wherein the content of the first and second substances,is a random perturbation component.

In the general case of the above-mentioned,. If it is paired withDiscrete Fourier Transform (DFT) is performed to obtainThen in the frequency spectrumThe cumulative amplitude of the position signal should be much larger than the cumulative amplitude of the disturbance component. Can be directly according toPeak of spectrum, pairAnd (6) estimating. Thus, we obtain:

。

finally, the spurious signal is defined as:

；

or

；

WhereinChannel coefficient as spur. Then, based on the estimated channel amplitude coefficients, the estimated encoded signal that can be reconstructed is:

。

based on the above definition, the target detection method based on the MIMO radar of the present invention is specifically implemented by the following steps:

step 501, storing the ADC sampling data of the original echoes of each Chirp to form a data matrix. Wherein the sampling length isChirp number of。

In step 502, target echoes of the random coding MIMO radar at different distances (corresponding to different echo frequencies) are overlapped in the time domain, so that it is difficult to estimate the target echoes directly in the time domain. Therefore, the signal needs to be converted to the frequency domain by FFT for processing. Therefore, it is toEach column of is made to be of length（) Obtaining a one-dimensional FFT processing result。

Step 503, setting the CLEAN cycle number asSetting a cycle countAnd a successive CLEAN process is started.

Step 504, for the data matrixFirst, theDoppler data of a lineDecoding to obtain a decoding matrix. Assume a matrix of coding coefficients of

；

Wherein M is the number of transmitting channels. Suppose thatCode element ofAnd is andobeying a two-dimensional normal distribution with a phase quantization bit number of. Then there are:

；

the decoded data vector is then:

。

step 505, for the data matrixIs made of data of all columns of length Obtaining Doppler spectrum data of the FFT of (1)。

Step 506, forThe square of the amplitude is obtained and accumulated according to the transmitting channel to obtain. Expressed as:

。

step 507, data acquisitionMaximum value ofAnd its positionThen make a request forMean value of。

Step 508, setting a preset detection threshold value。

If it isAnd jumping out of the CLEAN loop, finishing the operation and outputting an original coding signal of a target object (namely a weak target).

If it is，Step 509 is performed.

In step 509, ifAnd jumping out of the CLEAN loop, finishing the operation and outputting an original coding signal of a target object (namely a weak target).

Otherwise (i.e. the) Step 510 is performed.

Step 510, saving the target detection information and according to the spectral peak positionEstimating a normalized frequency of the targetComprises the following steps:

；

according to frequencyGenerating a unit signal：

。

511, according to the estimated peak positionFrom the matrixThe channel data of the corresponding position is taken out, so that the amplitude coefficient of each transmitting channel of the target can be estimatedI.e. by

。

Step 512, using the estimated channel amplitude coefficientGenerating a spurious signal，。

Step 513, utilizing the estimated spurAnd unit signalReconstructing the estimated encoded signal，。

Step 514, removing the encoded signal from the raw doppler data, which is expressed as:then, go to step 504.

Traversing the matrix according to the method of the steps 504 to 514And finally obtaining the original coded signal of the target object (namely the weak target) by the Doppler data of all the rows.

In summary, the present invention can prevent the situation that the doppler spurs of the strong target cover the echo signals of the weak target, which results in the missed detection of the weak target.

The following is illustrated by a simulation example.

Fig. 6 to 8 are schematic diagrams of simulation results provided by the present invention, as shown in fig. 6 to 8. Fig. 6-8 simulate 3 targets: distance = [100m,100m,100m ], velocity = [0m/s,10m/s, -5m/s ]. A preset detection threshold T =5 is set.

Fig. 6 is doppler spectrum data of a range bin in which a target is located. The figure simulates 3 targets: the distances are the same, the speeds are different, and the amplitudes are different. Therefore, the three targets are at the same range bin but the doppler frequencies are different. The spectral peak of one target (target with velocity of-5 m/s) is not visible in the figure because the spurs of strong targets mask the spectral peaks of weak targets.

Figure 7 is a comparison of doppler time domain data and the estimated encoded signal of the strongest target estimated under the current clear cycle.

FIG. 8 shows the results of the third CLEAN cycle.

The MIMO radar-based target detection apparatus provided by the present invention is described below, and the MIMO radar-based target detection apparatus described below and the MIMO radar-based target detection method described above may be referred to in correspondence with each other.

Fig. 9 is a schematic structural diagram of a target detection apparatus based on MIMO radar according to the present invention, as shown in fig. 9. An apparatus 900 for target detection based on MIMO radar includes a data obtaining module 910, a reconstructing module 920, and a detecting module 930. Wherein the content of the first and second substances,

a data obtaining module 910, configured to obtain original coded signals of multiple objects received by the MIMO radar.

A reconstructing module 920, configured to reconstruct an estimated encoding signal of a part of the objects based on the original encoding signal.

A detecting module 930, configured to remove the reconstructed estimated encoded signal of the part of the object from the original encoded signal, so as to obtain an original encoded signal of the target object.

Optionally, the data obtaining module 910 is further configured to perform the following steps:

sampling original coding signals in each linear frequency modulation pulse of the MIMO radar to obtain sample data;

generating a data matrix based on the sample data；

For the data matrixEach column of (a) is made to be of length（) To obtain a data matrix；

Wherein the content of the first and second substances,indicating the length of the sample data and N the number of chirps.

Optionally, the reconstructing module 920 is further configured to perform the following steps:

from the data matrixStarting with the first row of the data matrixAs the current row, each row in the previous part of rows performs the following steps 1-9:

step 1, for the data matrixDecoding the Doppler data of the current row to obtain a decoding matrix；

Step 2, decoding the matrixIs made of data of all columns of length Fourier transform of the Doppler spectrum data matrix to obtain the Doppler spectrum data matrix；

Step 3, aiming at the Doppler frequency spectrum data matrixThe square of the amplitude is calculated and accumulated according to the transmitting channel to obtain a data matrix；

Step 4, obtaining the data matrixMaximum value ofAnd its positionAnd evaluating said data matrixAverage value of (2)；

Step 5, according to the positionEstimating the normalized frequency of the object to which it correspondsAnd generating a unit signal from the normalized frequencyWherein=/；

Step 6, according to the positionFrom said Doppler frequency data matrixExtracting channel data of corresponding position to obtain amplitude coefficient of each emission channel of object corresponding to the position；

Step 7, utilizing the amplitude coefficient of each transmitting channelGenerating a spurious signal；

Step 8, according to the stray signalAnd the unit signalReconstructing an estimated encoded signal of the object corresponding to the locationWherein。

Illustratively, the detecting module 930 is further configured to perform the following steps:

after each execution of the steps 1-8, the following step 9 is executed:

step 9, encoding the estimated code signalFrom the data matrixIs removed from the doppler data of the current line.

Optionally, the reconstructing module 920 is further configured to perform the following steps:

thresholding the number of cycles before the initial execution of said step 1Set to a predetermined initial value and count cyclesIs 0, then after each execution of said step 4 the following operations are performed:

if the maximum value obtained in the step 4 is the maximum valueSatisfies the conditionsIf yes, jumping out of the cycle and finishing the whole reconstruction and elimination operation;

if the maximum value obtained in the step 4 is the maximum valueSatisfies the conditionsThen give an orderAnd if newly assignedIf yes, jumping out of the loop and finishing the whole reconstruction and elimination operation, otherwise, continuing to execute the subsequent step 5;

wherein, T is a preset detection threshold value.

Other aspects of the MIMO radar-based target detection apparatus disclosed by the present invention are the same as or similar to those of the MIMO radar-based target detection method described above, and are not described herein again.

Fig. 10 illustrates a physical structure diagram of an electronic device, and as shown in fig. 10, the electronic device may include: a processor (processor)1010, a communication Interface (Communications Interface)1020, a memory (memory)1030, and a communication bus 1040, wherein the processor 1010, the communication Interface 1020, and the memory 1030 communicate with each other via the communication bus 1040. Processor 1010 may invoke logic instructions in memory 1030 to perform any of the MIMO radar-based target detection methods described above.

Furthermore, the logic instructions in the memory 1030 can be implemented in software functional units and stored in a computer readable storage medium when the logic instructions are sold or used as independent products. 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 and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

In yet another aspect, the present invention also provides a non-transitory computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements any of the MIMO radar-based target detection methods described above.

The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.