Method and device for purifying direct wave signal of external radiation source radar, medium and program

Abstract

This invention provides a method, apparatus, medium, and program for purifying direct-wave signals from an external radiation source radar. The method involves preprocessing the received signal from the echo channel based on a blocking matrix to obtain a preprocessed signal; then, based on the received signal from the reference channel and the preprocessed signal, adaptive weighting coefficients for sidelobe cancellation are calculated; subsequently, the preprocessed signal is weighted based on these adaptive weighting coefficients to obtain estimates of multipath clutter and co-channel interference; finally, these estimates are removed from the received signal from the reference channel to obtain the purified direct-wave signal. This signal purification method utilizes sidelobe cancellation to eliminate multipath clutter and co-channel interference mixed into the reference channel, achieving direct-wave signal purification. Compared to existing purification methods, it eliminates the need for complex calculations, prior knowledge of the direct-wave structure characteristics, and signal sparsity requirements, thus exhibiting strong applicability.

Description

Technical Field

[0001] This invention belongs to the field of radar and communication integration technology, specifically relating to a method, device, medium, and program for purifying direct wave signals from external radiation source radar. Background Technology

[0002] External radiation source radars typically employ two receiving channels: a reference channel and an echo channel. The reference channel receives the direct wave signal from the external radiation source, while the echo channel receives the target echo signal. Matched correlation processing is applied to both signals to achieve target detection and localization. In practice, the reference channel inevitably receives multipath clutter and co-channel interference in addition to the direct wave signal. When performing matched correlation processing, false target peaks are generated, which can cause severe false alarms. Therefore, it is necessary to eliminate multipath clutter and co-channel interference, i.e., to refine the direct wave signal received by the reference channel.

[0003] In recent years, direct wave signal purification technology has received much attention. There are purification methods based on array signal spatial projection (Chen Gang, Wang Jun, Wang Jue. Reference signal purification method for external radiation source radar [J]. Systems Engineering and Electronics, 2018, 40(01): 113-117.), reference signal purification methods based on demodulation reconstruction (Chang Meng. Research on DRM shortwave external radiation source radar reference signal reconstruction and direct wave suppression technology [M], Master's thesis of Harbin Institute of Technology, 2022), and purification methods based on signal sparsity (Ying Tao, Wang Xuebao, Tian Wei. A new method for reference signal purification in non-cooperative passive detection [J]. Acta Aeronautica Sinica, 2022, 43(02): 410-419). These achievements have promoted the development of direct wave purification technology and laid the foundation for further research. However, the above methods involve complex calculations, require knowledge of the structural characteristics of radar signals, or require radar signals to have sparsity, so they have significant limitations in practical applications. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method, apparatus, medium, and program for purifying direct wave signals from external radiation source radar, thereby solving the problem of purifying direct wave signals under multipath clutter and co-frequency interference.

[0005] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0006] A method for purifying direct wave signals from external radiation source radar, characterized in that:

[0007] Step 1, based on the blocking matrix Received signal for echo channel Preprocessing is performed to obtain the preprocessed signal. :

[0008]

[0009] In the formula, superscript Indicates conjugate transpose;

[0010] Step 2, receive signal based on reference channel and preprocessed signals Calculate the adaptive weighting coefficients for sidelobe cancellation. :

[0011]

[0012] In the formula, , , Indicates taking the average, superscript Indicates conjugate;

[0013] Step 3, based on adaptive weight coefficients Preprocessed signals Weighted processing is performed to obtain estimates of multipath clutter and co-channel interference. :

[0014]

[0015] Step 4, the estimated Receive signal from reference channel After removing the impurities, the purified direct wave signal is obtained.

[0016] Furthermore, the blocking matrix satisfies the following condition:

[0017]

[0018] In the formula, This is the steering vector for the direct wave signal.

[0019] Furthermore, the blocking matrix for:

[0020]

[0021] In the formula, , For wavelength, For the spacing between array elements, The direction of the direct wave signal, It is the imaginary unit.

[0022] Furthermore, the reference channel receives signals. Represented as:

[0023]

[0024] In the formula, It is a direct wave signal. The amplitude of the direct wave signal. For the first Multipath clutter, For the first The amplitude of multipath clutter, The number of multipath clutter, For the first One co-frequency interference, for The amplitude of co-frequency interference, The number of co-channel interferences, This is background noise.

[0025] Furthermore, the echo channel receives signals. Represented as:

[0026]

[0027] In the formula, For the target echo signal, It is a direct wave signal. The steering vector of the target echo signal. The steering vector for the direct wave signal. For the first Multipath clutter, For the first A steering vector for multipath clutter. The number of multipath clutter, For the first One co-frequency interference, For the first The steering vector of a co-channel interference, The number of co-channel interferences, This is the background noise vector.

[0028] Furthermore, the reference channel receives direct wave signals from external radiation sources via a high-gain antenna.

[0029] Furthermore, the echo channel receives the target echo signal through an antenna array.

[0030] A computer device, including a memory and a processor;

[0031] The memory is used to store computer programs;

[0032] The processor is used to execute the computer program and, in executing the computer program, implement the above-described method for purifying direct wave signals from external radiation source radar.

[0033] A computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the above-described method for purifying direct wave signals from external radiation source radar.

[0034] A computer program product includes a computer program that, when executed by a processor, implements the above-described method for purifying direct-wave signals from external radiation sources radar.

[0035] The beneficial effects of this invention are as follows:

[0036] (1) This invention provides a method for purifying direct wave signals from external radiation source radar. It utilizes sidelobe cancellation to eliminate multipath clutter and co-frequency interference mixed in the reference channel, thereby achieving direct wave signal purification. Compared with existing purification methods such as spatial projection, demodulation and reconstruction, and sparsity, this invention does not require complex calculations, knowledge of the direct wave structure characteristics, or signal sparsity requirements, and has strong applicability.

[0037] (2) The main processing of this invention is to obtain a preprocessed signal using the blocking matrix, then use this signal to calculate the adaptive weighting coefficients for sidelobe cancellation, and finally obtain the estimates of multipath clutter and co-channel interference and eliminate them from the received signal of the reference channel. The whole processing is very simple and has high robustness. Attached Figure Description

[0038] Figure 1 This is a flowchart of the signal purification method of the present invention;

[0039] Figure 2 This is a schematic diagram illustrating the principle of sidelobe cancellation in this invention;

[0040] Figure 3 This is a diagram of the pure direct wave signal in the test example;

[0041] Figure 4 A diagram of the reference channel received signal before multipath clutter and co-channel interference cancellation;

[0042] Figure 5 The difference between the pure direct wave signal and the received signal from the reference channel before cancellation;

[0043] Figure 6 Diagram of the reference channel received signal after multipath clutter and co-channel interference cancellation;

[0044] Figure 7 This is the difference between the pure direct wave signal and the received signal from the reference channel after cancellation. Detailed Implementation

[0045] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0046] I. Technical Solution

[0047] This invention provides a method for purifying direct wave signals from external radiation source radar based on sidelobe cancellation, which can effectively eliminate multipath clutter and co-channel interference mixed in the radar reference channel, thereby obtaining a pure direct wave signal.

[0048] Reference Figure 1 and Figure 2 As shown, the signal purification method of the present invention specifically includes the following:

[0049] 1. External Radar Source Received Signal Model

[0050] The signals received by both the radar reference channel and the echo channel are modeled as follows:

[0051] 1.1, Reference Channel

[0052] The radar reference channel is equipped with a dedicated high-gain antenna to receive direct wave signals from external radiation sources. However, it inevitably receives multipath clutter and co-channel interference. Therefore, the received signal of the reference channel... Represented as:

[0053]

[0054] In the formula, It is a direct wave signal. The amplitude of the direct wave signal. For the first Multipath clutter, For the first The amplitude of multipath clutter, The number of multipath clutter, For the first One co-frequency interference, for The amplitude of co-frequency interference, The number of co-channel interferences, For background noise, It is a discrete-time variable.

[0055] 1.2, Echo Channel

[0056] The radar echo channel uses an antenna array to receive target echo signals. However, it inevitably receives direct wave signals from external radiation sources, multipath clutter, and co-channel interference. Therefore, the received signal in the echo channel... Represented as:

[0057]

[0058] In the formula, For the target echo signal, The steering vector of the target echo signal. The steering vector for the direct wave signal. For the first A steering vector for multipath clutter. For the first The steering vector of a co-channel interference, This is the background noise vector.

[0059] 2. Adaptive weighting coefficients for sidelobe cancellation

[0060] Calculate the adaptive weighting coefficients for sidelobe cancellation using the received signals from the reference channel and the echo channel:

[0061] 1) Set up a blocking matrix The conditions are met. superscript To represent the conjugate transpose, then The matrix expression is:

[0062]

[0063] In the formula, , For wavelength, For the spacing between array elements, The direction of the direct wave signal, The imaginary unit, ;

[0064] 2) Using matrices Received signal for echo channel Preprocessing is performed to obtain the preprocessed signal. :

[0065]

[0066] 3) Utilizing the received signal from the reference channel and preprocessed signals Calculate the adaptive weighting coefficients for sidelobe cancellation. :

[0067]

[0068] In the formula, , This indicates taking the average. superscript Indicates conjugate.

[0069] 3. Signal purification

[0070] The received signal in the echo channel is weighted using adaptive weighting coefficients to obtain estimates of multipath clutter and co-channel interference. These estimates are then removed from the received signal in the reference channel, resulting in a purified signal.

[0071] 1) Using adaptive weight coefficients Preprocessed signals Weighted processing is performed to obtain estimates of multipath clutter and co-channel interference. :

[0072]

[0073] 2) Receive signal from reference channel Estimation for eliminating the above multipath clutter and co-channel interference A pure direct wave signal estimate is obtained. :

[0074]

[0075] At this point, the multipath clutter and co-channel interference mixed in the radar reference channel received signal are eliminated, leaving only the pure direct wave signal from the external radiation source.

[0076] II. Testing and Verification

[0077] In this test, both the direct wave signal and multipath clutter used random frequency modulated (RF) waveforms, as did co-channel interference. The two RF waveforms were uncorrelated. The radar had two receiving channels: a reference channel and an echo channel. The reference channel used a high-gain antenna to receive signals from external radiation sources. The received signal consisted of direct wave, multipath clutter, co-channel interference, and background noise, as shown in Table 1. The background noise power was -20 dBW. The echo channel used a uniform linear array of 20 elements to receive signals from external radiation sources. The received signal also consisted of direct wave, multipath clutter, co-channel interference, and background noise, as shown in Table 2. The background noise power for each element was -20 dBW.

[0078] Table 1 Parameters of the received signal from the reference channel

[0079]

[0080] Table 2 Parameters of the received signal in the echo channel

[0081]

[0082] Figure 3 The image shows a pure direct wave signal. Figure 4 The image shows the received signal of the reference channel before purification processing. Its difference from the pure direct wave signal is as follows: Figure 5 As shown, due to the presence of multipath clutter and co-channel interference, the difference between the two is significant. The signal purification method of this invention is used to purify the received signal of the above-mentioned reference channel. The purified signal is as follows: Figure 6 As shown, its difference from a pure direct wave signal is as follows: Figure 7 As shown, the difference between the two is significantly reduced because multipath clutter and co-channel interference are effectively eliminated.

[0083] In summary, the direct wave signal purified by this invention is very close to the original pure direct wave signal, achieving the desired purpose and verifying that the signal purification method of this invention has a good direct wave signal purification effect.

[0084] III. Devices, storage media, and software products

[0085] 1. Based on the same inventive concept as the above-described method for purifying direct-wave signals from external radiation source radar, this application also provides an electronic device, which includes a processor and a memory. The memory stores computer-readable code, wherein when the computer-readable code is executed by the processor, the method for purifying direct-wave signals from external radiation source radar of the present invention is implemented.

[0086] The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium can store the operating system and computer-readable code. The computer-readable code includes program instructions that, when executed, cause the processor to perform a method for purifying direct-wave signals from an external radiation source radar. The processor provides computational and control capabilities to support the operation of the entire electronic device. The memory provides an environment for the execution of the computer-readable code in the non-volatile storage medium, which, when executed by the processor, causes the processor to perform a method for purifying direct-wave signals from an external radiation source radar.

[0087] It should be understood that a processor can be a central processing unit, other general-purpose processors, digital signal processors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, transistor logic devices, discrete hardware components, etc. Among them, a general-purpose processor can be a microprocessor or any conventional processor.

[0088] 2. This application also provides a readable storage medium, which may be an internal storage unit of the electronic device described in the foregoing embodiments, such as the hard disk or memory of the computer device. The readable storage medium may also be an external storage device of the electronic device, such as a plug-in hard disk, smart memory card, or secure digital card equipped on the electronic device.

[0089] 3. This application also provides a computer program product, including a computer program or instructions, which, when executed by a processor, implements the method for purifying direct wave signals from external radiation source radar according to the present invention.

[0090] This invention is not limited to the above-described embodiments. Any obvious improvements, substitutions, or modifications that can be made by those skilled in the art without departing from the essence of this invention are within the scope of protection of this invention.

Claims

1. A method for purifying direct-wave signals from an external radiation source radar, characterized in that: Step 1, based on the blocking matrix Received signal for echo channel Preprocessing is performed to obtain the preprocessed signal. : In the formula, superscript Indicates conjugate transpose; Step 2, receive signal based on reference channel and preprocessed signals Calculate the adaptive weighting coefficients for sidelobe cancellation. : In the formula, , , Indicates taking the average, superscript Indicates conjugate; Step 3, based on adaptive weight coefficients Preprocessed signals Weighted processing is performed to obtain estimates of multipath clutter and co-channel interference. : Step 4, the estimated Receive signal from reference channel After removing the impurities, the purified direct wave signal is obtained.

2. The method for purifying direct wave signals from external radiation source radar according to claim 1, characterized in that: The blocking matrix satisfies the following condition: In the formula, This is the steering vector for the direct wave signal.

3. The method for purifying direct wave signals from external radiation source radar according to claim 1, characterized in that: The blocking matrix for: In the formula, , For wavelength, For the spacing between array elements, The direction of the direct wave signal, It is the imaginary unit.

4. The method for purifying direct wave signals from external radiation source radar according to claim 1, characterized in that: The reference channel receives signals. Represented as: In the formula, It is a direct wave signal. The amplitude of the direct wave signal. For the first Multipath clutter, For the first The amplitude of multipath clutter, The number of multipath clutter, For the first One co-frequency interference, for The amplitude of co-frequency interference, The number of co-channel interferences, This is background noise.

5. The method for purifying direct wave signals from external radiation source radar according to claim 1, characterized in that: The echo channel receives signals. Represented as: In the formula, For the target echo signal, It is a direct wave signal. The steering vector of the target echo signal. The steering vector for the direct wave signal. For the first Multipath clutter, For the first A steering vector for multipath clutter. The number of multipath clutter, For the first One co-frequency interference, For the first The steering vector of a co-channel interference, The number of co-channel interferences, This is the background noise vector.

6. The method for purifying direct wave signals from external radiation source radar according to claim 1, characterized in that: The reference channel receives direct wave signals from external radiation sources via a high-gain antenna.

7. The method for purifying direct wave signals from external radiation source radar according to claim 1, characterized in that: The echo channel receives the target echo signal through an antenna array.

8. A computer device, characterized in that: Including memory and processor; The memory is used to store computer programs; The processor is used to execute the computer program and, in executing the computer program, implement the method for purifying direct wave signals from external radiation source radar as described in any one of claims 1 to 7.

9. A computer-readable storage medium, characterized in that: The system contains a computer program that, when executed by a processor, causes the processor to perform the method for purifying direct-wave signals from external radiation sources as described in any one of claims 1 to 7.

10. A computer program product, characterized in that: The method includes a computer program that, when executed by a processor, implements the method for purifying direct-wave signals from external radiation sources as described in any one of claims 1 to 7.

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