阅读说明：本技术 雷达主瓣干扰抑制方法及装置、电子设备、存储介质 (Radar main lobe interference suppression method and device, electronic equipment and storage medium ) 是由 宫健 郭艺夺 冯存前 李欣 王春阳 潘鑫锐 肖宇 陈赓 于 2020-06-18 设计创作，主要内容包括：本申请提供一种雷达主瓣干扰抑制方法及装置、电子设备、存储介质。该方法包括：接收第一雷达信号；对所述第一雷达信号进行去斜处理,获得第二雷达信号；根据所述第二雷达信号的峰值时刻,获得第一重构干扰信号；对所述第一重构干扰信号与第二雷达信号进行对消处理,获得目标回波信号。该方法实现了对雷达主瓣干扰的有效抑制。(The application provides a radar main lobe interference suppression method and device, electronic equipment and a storage medium. The method comprises the following steps: receiving a first radar signal; performing deskewing processing on the first radar signal to obtain a second radar signal; obtaining a first reconstruction interference signal according to the peak time of the second radar signal; and performing cancellation processing on the first reconstruction interference signal and the second radar signal to obtain a target echo signal. The method realizes effective suppression of the interference of the radar main lobe.)

1. A method for suppressing radar mainlobe interference, the method comprising:

receiving a first radar signal;

performing deskewing processing on the first radar signal to obtain a second radar signal;

obtaining a first reconstruction interference signal according to the peak time of the second radar signal;

and performing cancellation processing on the first reconstruction interference signal and the second radar signal to obtain a target echo signal.

2. The method of claim 1, wherein before obtaining the first reconstructed interference signal according to the peak time of the second radar signal, the method further comprises:

calculating a peak threshold according to the maximum peak value of the second radar signal;

and determining the peak value corresponding time higher than the peak value threshold as the peak value time of the second radar signal according to the peak value threshold.

3. The method according to claim 1, wherein the obtaining a first reconstructed interference signal according to the peak time of the second radar signal comprises:

determining instantaneous frequency corresponding to the interference component according to the peak time of the second radar signal;

and obtaining a first reconstruction interference signal according to the instantaneous frequency corresponding to the interference component.

4. The method according to claim 3, wherein the determining an instantaneous frequency corresponding to an interference component according to a peak time of the second radar signal comprises:

determining an instantaneous frequency corresponding to the ith interference component according to the peak time of the second radar signal by adopting the following formula:

f_re(i)＝-μ[t_st(i)-t_ref]

wherein, t_st(i) Denotes the ith peak time, t_refWhich represents the reference signal delay in the deskew process and mu represents the chirp rate of the signal.

5. The method for suppressing radar main lobe interference according to claim 1, wherein the performing cancellation processing on the first reconstructed interference signal and the second radar signal to obtain a target echo signal includes:

calculating an optimal interference suppression factor;

and utilizing the optimal interference suppression factor to perform cancellation processing on the first reconstructed interference signal and the second radar signal to obtain a target echo signal.

6. The radar mainlobe interference suppression method according to claim 5, wherein the calculating an optimal interference suppression factor comprises:

calculating an average detection threshold corresponding to each value of the interference suppression factors in the search range according to a preset search range and a preset step length;

and selecting the corresponding interference suppression factor as the optimal interference suppression factor when the average detection threshold is the minimum value.

7. The method according to claim 5, wherein the obtaining a target echo signal by performing cancellation processing on the first reconstructed interference signal and the second radar receiving signal by using the optimal interference suppression factor includes:

performing Fourier transform and modulus taking on the first reconstruction interference signal to obtain a second reconstruction interference signal;

performing Fourier transform and modulus taking on the second radar receiving signal to obtain a third radar receiving signal;

obtaining a target echo signal by adopting the following formula:

|S_re(f)|＝|R_st(f)|-w_opt|J_re(f)|

wherein, | J_re(f) L represents a second reconstructed interference signal, | R_st(f) L represents a third radar reception signal, w_optRepresents the best interference suppression factor, | S_re(f) And | represents the target echo signal.

8. A radar mainlobe interference suppression apparatus, the apparatus comprising:

the signal acquisition module is used for receiving a first radar signal;

the deskew processing module is used for deskewing the first radar signal to obtain a second radar signal;

the reconstruction interference signal acquisition module is used for acquiring a first reconstruction interference signal according to the peak time of the second radar signal;

and the cancellation processing module is used for performing cancellation processing on the first reconstruction interference signal and the second radar signal to obtain a target echo signal.

9. An electronic device, characterized in that the electronic device comprises:

a processor;

a memory for storing processor-executable instructions;

wherein the processor is configured to perform the radar mainlobe interference mitigation method of any of claims 1-7.

10. A computer-readable storage medium, characterized in that the storage medium stores a computer program executable by a processor to perform the radar mainlobe interference suppression method of any one of claims 1 to 7.

Technical Field

The present disclosure relates to the field of radar technologies, and in particular, to a method and an apparatus for suppressing radar main lobe interference, an electronic device, and a storage medium.

Background

Radars are electronic devices that detect objects using electromagnetic waves. The radar emits electromagnetic waves to irradiate a target and receives the echo of the target, so that information such as the distance from the target to an electromagnetic wave emission point, the distance change rate (radial speed), the azimuth and the altitude is obtained. When the echo signal of the radar is interfered, the accuracy of the radar for acquiring the target information is influenced.

The frequency shift forwarding interference signal is an interference signal generated after frequency modulation is carried out on a radar transmission signal. Usually, the pulse width of the frequency-shift repeating interference signal is the same as that of the radar signal, and both the frequency-shift repeating interference signal and the radar signal have overlapping in time domain and frequency domain. Therefore, the interference signals cannot be effectively suppressed by adopting the conventional time domain gating and frequency domain filtering method.

Disclosure of Invention

The embodiment of the application provides a radar main lobe interference suppression method, which effectively realizes suppression of radar interference signals.

The application provides a radar main lobe interference suppression method, which comprises the following steps:

receiving a first radar signal;

performing deskewing processing on the first radar signal to obtain a second radar signal;

obtaining a first reconstruction interference signal according to the peak time of the second radar signal;

and performing cancellation processing on the first reconstruction interference signal and the second radar signal to obtain a target echo signal.

In an embodiment, before obtaining the first reconstructed interference signal according to the peak time of the second radar signal, the method further includes:

calculating a peak threshold according to the maximum peak value of the second radar signal;

and determining the peak value corresponding time higher than the peak value threshold as the peak value time of the second radar signal according to the peak value threshold.

In an embodiment, the obtaining a first reconstructed interference signal according to a peak time of the second radar signal includes:

determining instantaneous frequency corresponding to the interference component according to the peak time of the second radar signal;

and obtaining a first reconstruction interference signal according to the instantaneous frequency corresponding to the interference component.

In an embodiment, the determining an instantaneous frequency corresponding to an interference component according to a peak time of the second radar signal includes:

determining an instantaneous frequency corresponding to the ith interference component according to the peak time of the second radar signal by adopting the following formula:

f_re(i)＝-μ[t_st(i)-t_ref]

wherein, t_st(i) Denotes the ith peak time, t_refWhich represents the reference signal delay in the deskew process and mu represents the chirp rate of the signal.

In an embodiment, the performing cancellation processing on the first reconstructed interference signal and the second radar signal to obtain a target echo signal includes:

calculating an optimal interference suppression factor;

and utilizing the optimal interference suppression factor to perform cancellation processing on the first reconstructed interference signal and the second radar signal to obtain a target echo signal.

In one embodiment, the calculating the optimal interference suppression factor includes:

calculating an average detection threshold corresponding to each value of the interference suppression factors in the search range according to a preset search range and a preset step length;

and selecting the corresponding interference suppression factor as the optimal interference suppression factor when the average detection threshold is the minimum value.

In an embodiment, the performing cancellation processing on the first reconstructed interference signal and the second radar receiving signal by using the optimal interference suppression factor to obtain a target echo signal includes:

performing Fourier transform and modulus taking on the first reconstruction interference signal to obtain a second reconstruction interference signal;

performing Fourier transform and modulus taking on the second radar receiving signal to obtain a third radar receiving signal;

obtaining a target echo signal by adopting the following formula:

|S_re(f)|＝|R_st(f)|-w_opt|J_re(f)|

wherein, | J_re(f) L represents a second reconstructed interference signal, | R_st(f) L represents a third radar reception signal, w_optRepresents the best interference suppression factor, | S_re(f) And | represents the target echo signal.

On the other hand, the present application also provides a radar main lobe interference suppression device, the device includes:

the signal acquisition module is used for receiving a first radar signal;

the deskew processing module is used for deskewing the first radar signal to obtain a second radar signal;

the reconstruction interference signal acquisition module is used for acquiring a first reconstruction interference signal according to the peak time of the second radar signal;

and the cancellation processing module is used for performing cancellation processing on the first reconstruction interference signal and the second radar signal to obtain a target echo signal.

Further, the present application also provides an electronic device, including:

a processor;

a memory for storing processor-executable instructions;

wherein the processor is configured to execute the radar main lobe interference suppression method provided by the embodiment of the application.

Further, the present application also provides a computer-readable storage medium, where the storage medium stores a computer program, and the computer program is executable by a processor to complete the radar mainlobe interference suppression method provided in the embodiments of the present application.

According to the technical scheme provided by the embodiment of the application, the first radar signal is subjected to deskew processing through receiving the first radar signal, the second radar signal is obtained, the first reconstruction interference signal is obtained according to the peak time of the second radar signal, the first reconstruction interference signal and the second radar signal are subjected to cancellation processing, the target echo signal is obtained, and suppression of radar main lobe interference is effectively achieved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly described below.

Fig. 1 is a schematic view of an application scenario of a radar main lobe interference suppression method according to an embodiment of the present application;

fig. 2 is a schematic flowchart of a radar main lobe interference suppression method according to an embodiment of the present application;

FIG. 3 is a time domain diagram of a second radar signal provided by an embodiment of the present application;

fig. 4 is a time domain diagram of a first reconstructed interference signal according to an embodiment of the present application;

FIG. 5 is a graph illustrating a variation of an average detection threshold according to an embodiment of the present application;

FIG. 6 is a time domain diagram of a target echo signal according to an embodiment of the present application;

fig. 7 is a block diagram of a radar main lobe interference suppression apparatus according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

Like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present application, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.

Fig. 1 is a schematic view of an application scenario of a radar main lobe interference suppression method according to an embodiment of the present application. The application scenario includes a server 110. The server 110 may be a server, a server cluster, or a cloud computing center. The server 110 may implement the method for suppressing radar main lobe interference provided by the embodiment to effectively suppress radar main lobe interference.

In an embodiment, the application scenario may further include a radar 120. The radar 120 emits electromagnetic waves to the target to irradiate the target and receive the echo of the target, the server 110 can acquire the echo signal of the radar from the radar 120, and then the server 110 can adopt the method provided by the application to realize suppression of radar main lobe interference.

The application also provides an electronic device. The electronic device may be the server 110 shown in fig. 1. As shown in fig. 1, the server 110 may include a processor 111 and a memory 112 for storing instructions executable by the processor 111; wherein the processor 111 is configured to execute the radar mainlobe interference suppression method provided by the present application.

The Memory 112 may be implemented by any type of volatile or non-volatile Memory device or combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic Memory, flash Memory, magnetic disk or optical disk.

The present application also provides a computer-readable storage medium storing a computer program executable by the processor 111 to perform the radar mainlobe interference suppression method provided by the present application.

Fig. 2 is a schematic flowchart of a radar main lobe interference suppression method according to an embodiment of the present application. As shown in fig. 2, the method comprises the following steps S210-S240.

Step S210: a first radar signal is received.

The first radar signal refers to an echo signal directly received by radar equipment. In this step, the received first radar signal includes a target echo signal and an interference signal. The interference signal may be a main lobe interference, and the main lobe interference refers to interference coming from a radar main lobe.

Step S220: and performing deskewing processing on the first radar signal to obtain a second radar signal.

The first radar signal may be represented as a superposition of the target echo signal and the interfering signal. Let the distance of the target be R_tThe target echo signal can be expressed as

Wherein f is₀For radar carrier frequency, μ represents the chirp rate of the signal, T represents the pulse width of the signal, Δ T₁＝2R_tC is the two-way propagation delay time of the target echo,

representing the phase of the echo signal.

The frequency-shifted interference signal may be represented as

Deskew processing refers to the multiplication of a received echo signal by the complex conjugate of a reference signal in radar signal processing. The reference signal is a signal which is the same as the frequency modulation slope of the radar transmitting signal and is obtained after delaying for a plurality of units. The reference signal can be expressed as

s_ref(t)＝exp[j2πf₀(t-t_ref)+jπμ(t-t_ref)²](3)

Wherein, t_refRepresenting the delay of the reference signal relative to the transmitted signal.

In this step, a second radar signal is obtained after deskewing.

Step S230: and obtaining a first reconstruction interference signal according to the peak time of the second radar signal.

The deskewed interference signal may be expressed as

Fourier transform is carried out on the interference signal subjected to the deskew processing, and then a module is taken, so that the following can be obtained:

as can be seen from equation (5), after the deskew processing, the multiple frequency-shifted interference signals are converted into a superposition of multiple single-frequency signals, i.e., multiple false targets distributed independently are generated.

In this step, according to the energy characteristic of the main lobe interference, the energy of the interference signal is much stronger than that of the target echo, and the peak time of the interference signal is easily identified. And reconstructing the interference signal after the deskew processing according to the peak time of the interference signal in the second radar signal to obtain a first reconstructed interference signal. The first reconstructed interfering signal has the same peak position as the received interfering signal.

Step S240: and performing cancellation processing on the first reconstruction interference signal and the second radar signal to obtain a target echo signal.

The cancellation processing refers to canceling the first reconstructed interference signal in the second radar signal. As can be seen from step S230, the peak positions of the first reconstructed interference signal and the received interference signal are the same, so that the first reconstructed interference signal and the second radar signal can be subjected to cancellation processing to obtain a target echo signal.

According to the technical scheme provided by the embodiment of the application, the first radar signal is subjected to deskew processing through receiving the first radar signal, the second radar signal is obtained, the first reconstruction interference signal is obtained according to the peak time of the second radar signal, the first reconstruction interference signal and the second radar signal are subjected to cancellation processing, the target echo signal is obtained, and suppression of radar main lobe interference is effectively achieved.

In an embodiment, before obtaining the first reconstructed interference signal according to the peak time of the second radar signal, the method further includes: calculating a peak threshold according to the maximum peak value of the second radar signal; and determining the peak value corresponding time higher than the peak value threshold as the peak value time of the second radar signal according to the peak value threshold.

After the deskewing process, the energy of the interference signal is obviously stronger than that of the target echo, so that a peak threshold can be determined, and the time corresponding to the peak higher than the peak threshold is determined to be generated by the interference signal. In this step, a peak threshold is first calculated based on the maximum peak of the second radar signal. In one embodiment, the maximum peak value minus 10dB may be used as the peak threshold. And then, according to the peak value threshold, determining that the corresponding moment of the peak value higher than the peak value threshold is the peak value moment of the second radar signal.

In an embodiment, the obtaining a first reconstructed interference signal according to a peak time of the second radar signal includes: determining instantaneous frequency corresponding to the interference component according to the peak time of the second radar signal; and obtaining a first reconstruction interference signal according to the instantaneous frequency corresponding to the interference component.

As can be seen from equation (5), after the deskew processing, the multiple frequency-shifted interference signals are transformed into a superposition of multiple single-frequency signals, and the instantaneous frequency of the ith interference component is:

f_st(i)＝f_i-f₀-μΔt₂+μt_ref(6)

the ith interference component corresponds to a peak time of

t_st(i)＝-(f_i-f₀)/μ+Δt₂(7)

As can be seen from equations (6) and (7), the instantaneous frequency of the deskewed interference component corresponds to the peak time. Thus, although the starting frequency f of the interference component is not known_iThe instantaneous frequency of the deskewed interference component corresponding to the peak time can still be reconstructed from the deskewed signal peak time.

In an embodiment, the following formula may be adopted to determine the instantaneous frequency corresponding to the i-th interference component according to the peak time of the second radar signal:

f_re(i)＝-μ[t_st(i)-t_ref](8)

the formula (8) can be derived from the combination of the formula (6) and the formula (7). Due to the chirp rate mu of the signal and the time delay t of the reference signal_refAre known, based on the peak time t of the ith interference signal_st(i) The instantaneous frequency f corresponding to the ith interference component can be determined_re(i)。

And then, according to the instantaneous frequency corresponding to the ith interference component, reconstructing the amplitude normalized interference signal after the deskew processing to obtain a first reconstructed interference signal. The first reconstructed interfering signal may be represented as:

in an embodiment, performing cancellation processing on the first reconstructed interference signal and the second radar signal to obtain a target echo signal may include: calculating an optimal interference suppression factor; and utilizing the optimal interference suppression factor to perform cancellation processing on the first reconstructed interference signal and the second radar signal to obtain a target echo signal.

Although the respective frequency components of the first reconstructed interfering signal are known, the relationship between the amplitude of the decoys in the received signal and the amplitude of the reconstructed decoys is unknown, and therefore the received signal cannot be directly subtracted from the first reconstructed interfering signal to obtain the target echo signal. The interference suppression factor is a linear adjustment of the amplitude of the first reconstructed interference signal. The optimal interference suppression factor means that when the interference suppression factor is at this value, the target echo in the received signal is most easily detected. In an embodiment, the canceling the first reconstructed interference signal and the second radar signal by using the interference suppression factor to obtain the target echo signal may include:

fourier transform and modulus taking are carried out on the first reconstruction interference signalObtaining a second reconstructed interference signal | J_re(f) The second reconstructed interference signal may be expressed as:

fourier transform and modulus taking are carried out on the second radar receiving signal to obtain a third radar receiving signal | R_st(f)|；

Obtaining a target echo signal by adopting the following formula:

|S_re(f)|＝|R_st(f)|-w_opt|J_re(f)| (11)

wherein, | J_re(f) L represents a second reconstructed interference signal, | R_st(f) L represents a third radar reception signal, w_optRepresents the best interference suppression factor, | S_re(f) And | represents the target echo signal.

In one embodiment, calculating the optimal interference suppression factor may include: calculating an average detection threshold corresponding to each value of the interference suppression factors in the search range according to a preset search range and a preset step length; and selecting the corresponding interference suppression factor as the optimal interference suppression factor when the average detection threshold is the minimum value.

Wherein the preset search range can be determined according to the strength of the interference, and is usually 0-30 dB. The average detection threshold is a detection threshold calculated by using a unit average constant false alarm rate (CA-CFAR) detection principle. According to parameters of the linear frequency modulation signal, 2/B is taken as the width of the detection unit, and the number of protection units on two sides of the unit to be detected is N_pThe number of reference cells is N_r(i.e., each of the right and left N_r2) false alarm probability of P_faThen, for the ith distance resolution unit, the detection threshold is:

Th_i＝ρZ (12)

wherein the content of the first and second substances,represents N_rThe corresponding amplitudes of the individual reference cells are averaged,representing a threshold weighting factor.

And (3) substituting each value of the interference suppression factors in the search range into an equation (11) according to a preset search range and a preset step length, and calculating an average detection threshold corresponding to each interference suppression factor according to a unit average constant false alarm rate (CA-CFAR) detection principle. And then selecting the corresponding interference suppression factor as the optimal interference suppression factor when the average detection threshold is the minimum value, wherein the optimal interference suppression factor is obtained after the formula (11) is followed, namely the target echo signal.

In one embodiment, simulation software is used to simulate the interference suppression process of radar signal, and the simulation parameters are that the radar emission pulse width is 50 mus, and the frequency modulation slope is 10 × 10⁴MHz/s, corresponding bandwidth of B5 MHz, and deskew reference window width of T_refThe frequency shift parameter of the multiple frequency shift interference is delta f (100 mu s)_i＝[-0.2,-0.3,0.1,0.2,0.3]And B, the interference-signal ratio is JSR (25 dB), and the signal-to-noise ratio SNR (signal-to-noise ratio) is 10 dB. The first radar signal generated by simulation is subjected to deskewing to obtain a second radar signal, and the second radar signal is shown in fig. 3.

From fig. 3, the peak time instant of the second radar signal can be determined. Fig. 3 shows that the maximum peak value of the second radar signal is around 25dB, and the peak threshold is 15dB by subtracting 10dB from the maximum peak value. Then, finding the peak position higher than 15dB, and substituting the formula (8) to obtain the instantaneous frequency of the interference component as-1.5 MHz, -1MHz, 0.5MHz, 1MHz and 1.5MHz according to the preset time delay of the reference signal. The first reconstructed interference signal can be obtained by substituting equation (9) according to the instantaneous frequency of the interference component, as shown in fig. 4.

Subsequently, the search range of the interference suppression factor is set to [0, 100 ]]And the step amount is 0.01, and according to the method provided in the foregoing embodiment, an average detection threshold corresponding to each interference suppression factor is calculated, as shown in fig. 5. As can be seen from fig. 5, when the interference suppression factor is w equal to 17.86, the average detection threshold is the minimum value, and w is obtained by converting w equal to 17.86 into dB value_opt25.0376. This is compared to the interference-to-signal ratio of the simulated initial settingsThe JSR is very close to 25dB, which shows the feasibility of the method. The target echo signal after interference suppression is shown in fig. 6.

The following are embodiments of the apparatus of the present application, which can be used to implement the above embodiments of the radar main lobe interference suppression method of the present application. For details that are not disclosed in the embodiments of the apparatus of the present application, please refer to the embodiments of the radar main lobe interference suppression method of the present application.

Fig. 7 is a block diagram of a radar main lobe interference suppression apparatus according to an embodiment of the present application. As shown in fig. 7, the apparatus includes: a signal acquisition module 710, a deskew processing module 720, a reconstructed interference signal acquisition module 730, and a cancellation processing module 740.

A signal acquisition module 710 for receiving the first radar signal.

And a deskew processing module 720, configured to perform deskew processing on the first radar signal to obtain a second radar signal.

A reconstructed interference signal obtaining module 730, configured to obtain a first reconstructed interference signal according to the peak time of the second radar signal.

And a cancellation processing module 740, configured to perform cancellation processing on the first reconstructed interference signal and the second radar signal, so as to obtain a target echo signal.

The implementation process of the functions and actions of each module in the above device is specifically described in the implementation process of the corresponding step in the above radar main lobe interference suppression method, and is not described herein again.

In the embodiments provided in the present application, the disclosed apparatus and method can be implemented in other ways. The apparatus embodiments described above are merely illustrative, and for example, the flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

In addition, functional modules in the embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

The functions, if implemented in the form of software functional modules and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including 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 application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.