Digital array hiding method based on radar protection antenna ASLC

Abstract

The invention belongs to a radar detection technology, and particularly relates to a digital array hiding method based on radar protection antenna ASLC, which takes a sum-path antenna sub-array as an auxiliary channel, cancels sidelobe interference of a protection antenna, completes the restoration of the protection antenna, recovers the interfered protection antenna, and selects a sample point the same as an ADBF to complete the hiding of the digital array. The ASLC and the ADBF have the same interference suppression degree, the protection antenna can reserve all information except the sidelobe interference angle, and hiding processing can be well carried out on non-cooperative targets and clutter signals.

Description

Technical Field

[0001] The present application relates to radar detection technology, and specifically to a digital array concealment method based on radar protection antenna ASLC. Background Art

[0002] Radar adaptive beamforming technology (ADBF) is a beam control technology for array receiving signals when adaptive antenna arrays are used in complex signal environments. Its basic principle is to calculate the optimal weights based on the optimization criteria through an adaptive algorithm, and then perform weighted summation on each sub-array so that the array output produces different responses to signals in different spatial directions.

[0003] Radar adaptive antenna sidelobe cancellation (ASLC) is a commonly used radar anti-active interference technology. The main lobe of the radar receiving antenna is very narrow and has a high gain, which is highly directional. The side lobes are very wide, and external interference signals can easily enter through the side lobes. ASLC uses the interference signal received by the auxiliary channel (usually the protection antenna) to cancel the interference signal coming in through the side lobes of the main channel (usually the sum antenna, including multiple sub-arrays).

[0004] Sidelobe hiding uses the characteristic that the protection antenna's gain is higher than the maximum sidelobe gain of the summing antenna to compare the protection antenna signal with the summing antenna signal. When the protection antenna signal is larger than the summing antenna signal, the signal is hidden to reduce false alarms entering the radar receiver from the sidelobes.

[0005] Currently, when ADBF takes effect, radar detection will cancel out the interference of the harmonic antenna signal, and the protection antenna will be interfered and the interference cannot be suppressed, so that the amplitude of the strong interference signal of the protection antenna is greater than the amplitude of the harmonic antenna signal after ADBF processing, resulting in the failure of stealth. There will be no target output after stealth processing. In view of this, the present application is proposed. Summary of the invention

[0006] The purpose of this application is to provide a digital array concealment method based on radar protection antenna ASLC to address the problem that the protection antenna cannot be concealed when the radar resists sidelobe interference. On the basis of the existing ADBF cancellation processing, the protection antenna after interference cancellation replaces the traditional protection antenna for sidelobe concealment.

[0007] The technical solution of this application is:

[0008] A digital array concealment method based on radar protection antenna ASLC, comprising:

[0009] Step 1: perform pulse compression and coherence processing on the sampled data of the subarray and the protection antenna, and perform interference detection to determine whether there is an interference signal. If there is an interference signal, proceed to step 2;

[0010] Step 2: determine the credible flag of the interference angle error. If the interference angle error is not credible and is sidelobe interference, proceed to step 3;

[0011] Step 3: Eliminate the main lobe signal and select the sample points of the side lobe signal;

[0012] Step 4: Take the protection antenna as the main channel and each subarray as the auxiliary channel to calculate the optimal weight W of ASLC opt (t);

[0013] Step 5: cancel the interference signal of the protection antenna sample point to obtain the cancelled protection antenna sample point signal S p (t)';

[0014] Step 6: Perform ADBF processing on the sample point signal of the combined antenna to obtain the sample point signal S of the combined antenna after ADBF processing. sum (t), and perform constant false alarm detection;

[0015] Step 7: Using the guard antenna sample point signal S after cancellation p (t)' and the ADBF processed and the antenna sample point signal S sum (t) To be kept anonymous.

[0016] According to at least one embodiment of the present application, in the above-mentioned digital array concealment method based on radar protection antenna ASLC, in step 2, the credible flag of the interference angle error is judged, and if the interference angle error is credible as main lobe interference, conventional concealment processing is performed.

[0017] According to at least one embodiment of the present application, in the digital array concealment method based on the radar protection antenna ASLC, in step 3, the main lobe signal is removed and the sample points of the side lobe signal are selected, specifically, S p0 (N ri ,N fj )>S sum0 (N ri ,N fj )-S limit The signal is removed and the sample points of the sidelobe signal are selected, where S p0 (N ri ,N fj ) is to protect the antenna signal; S sum0 (N ri ,N fj ) is the antenna signal; S limit To protect the antenna hidden threshold.

[0018] According to at least one embodiment of the present application, in the digital array concealment method based on the radar protection antenna ASLC, in step 4, the protection antenna is used as the main channel, and each sub-array is used as an auxiliary channel to calculate the optimal weight W of the ASLC. opt (t), specifically:

[0019]

[0020] in,

[0021] S sub (t) is the sub-array sample point signal;

[0022] is the conjugate transpose of the sub-array sample point signal;

[0023] To protect the conjugate transpose of the antenna sample point signal.

[0024] According to at least one embodiment of the present application, in the digital array concealment method based on the radar protection antenna ASLC, in step 5, the interference signal of the protection antenna sample point is cancelled to obtain the cancelled protection antenna sample point signal S p (t)', specifically:

[0025]

[0026] in,

[0027] S p (t) is the protection antenna sample point signal.

[0028] This application has at least the following beneficial technical effects:

[0029] A digital array concealment method based on radar protection antenna ASLC is provided. The sidelobe interference of the protection antenna is cancelled by using the antenna subarray as an auxiliary channel, and the protection antenna is restored. The interfered protection antenna is recovered. By selecting the same sample points as ADBF, ASLC and ADBF have the same degree of interference suppression. The protection antenna can retain all information except the sidelobe interference angle, and can better conceal non-cooperative targets and clutter signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of an applicable scenario of the digital array concealment method based on the radar protection antenna ASLC provided in this application;

[0031] Figure 2 The schematic diagram of the digital array concealment method based on the radar protection antenna ASLC provided in this application;

[0032] Figure 3A flowchart of a digital array cloaking method based on radar protection antenna ASLC provided in this application.

[0033] In order to better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. In addition, the drawings are only used for illustrative purposes and should not be construed as limitations on the present application. DETAILED DESCRIPTION

[0034] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be described in further detail in detail and in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design.

[0035] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application shall have the usual meanings understood by those of ordinary skill in the art to which this application belongs. The words used in the description of this application to indicate orientation are only used to indicate relative directions or positional relationships. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. The word "include" used in the description of this application indicates that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0036] In addition, it should be noted that, unless otherwise clearly specified and limited, the words "installation", "connection" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Technical personnel in the field can understand its specific meaning in this application according to the specific circumstances.

[0037] A digital array stealth method based on radar protection antenna ASLC is used to solve the problem of conventional stealth failure of radar after being interfered with by sidelobe. It is suitable for stealth processing in radar support interference scenarios, such as Figure 1 As shown in FIG. 1 , the ASLC processing is performed on the interference of the protection antenna using the multiple subarrays of the path antenna as auxiliary channels. The principle is as follows: Figure 2 As shown, the protection antenna signal after interference cancellation is obtained, and the protection antenna signal after cancellation and the summing antenna signal after ADBF are used for concealment processing, as shown in FIG. Figure 3 shown.

[0038] Step 1: Perform pulse compression and coherence processing on the sampled data of the sub-array and the protection antenna, and perform interference detection to determine whether there is an interference signal. If there is an interference signal, proceed to step 2.

[0039] Step 2: determine the credible sign of the interference angle error. If the interference angle error is credible as main lobe interference, perform conventional concealment processing. If the interference angle error is not credible as side lobe interference, proceed to step 3.

[0040] Step 3: Eliminate the main lobe signal and select the sample points of the side lobe signal.

[0041] S p0 (N ri ,N fj )>S sum0 (N ri ,N fj )-S limit The signal is removed and the sample points of the sidelobe signal are selected, where S p0 (N ri ,N fj ) is to protect the antenna signal; S sum0 (N ri ,N fj ) is the antenna signal; S limit To protect the antenna hidden threshold.

[0042] The number of sample points of the sidelobe signal is N. r , the Doppler gate number is N f , the range gate and Doppler gate positions are [(N r1 ,N f1 )(N r1 ,N f2 ),……(N ri ,N fi )],0 <i<N r ,0 <j<N f .

[0043] Step 4: Take the protection antenna as the main channel and each subarray as the auxiliary channel to calculate the optimal weight W of ASLC opt (t).

[0044] According to the minimum mean square error criterion, calculate the optimal weight W of ASLC opt (t):

[0045]

[0046] in,

[0047] S sub (t) is the sub-array sample point signal, S sub (t)=[S1,S2,...,SM ], M is the number of sub-arrays, The corresponding W opt (t) = [W opt (1),W opt (2),...,W opt (M)];

[0048] is the conjugate transpose of the sub-array sample point signal;

[0049] To protect the conjugate transpose of the antenna sample point signal.

[0050] Step 5: cancel the interference signal of the protection antenna sample point to obtain the cancelled protection antenna sample point signal S p (t)'.

[0051]

[0052] in,

[0053] S p (t) is the protection antenna sample point signal.

[0054] Step 6: Perform ADBF processing on the sample point signal of the combined antenna to obtain the sample point signal S of the combined antenna after ADBF processing. sum (t), and perform constant false alarm detection.

[0055] Step 7: Using the guard antenna sample point signal S after cancellation p (t)' and the ADBF processed and the antenna sample point signal S sum (t) To be kept anonymous.

[0056] In a specific scenario, the interference signal enters from the side lobe of the radar beam, ADBF takes effect, 8 subarrays are selected as the main channel, the carrier height H = 5000m, the target aircraft enters at a distance of R = 180km, the interference entry angle is 10°, the main lobe signal is removed, and the sample points of the side lobe signal are selected. The sample point signal S of each subarray sub (t) = [S1, S2, ..., S8], taking the protection antenna as the main channel, calculate the optimal weight W of ASLC opt (t):

[0057]

[0058] Cancel the interference signal of the protection antenna to obtain the sample point signal of the protection antenna after cancellation After the protection antenna is interfered, the spectrum power value is raised as a whole. At this time, the real-time noise of the protection antenna is 79.23dB. After ASLC processing, the sidelobe interference on the spectrum is basically cancelled, and the real-time noise is 65.22dB.

[0059] Perform ADBF processing on the sample point signal of the Helu antenna to obtain the sample point signal S of the Helu antenna after ADBF processing sum (t), the spectrum sidelobe interference after ADBF is basically completely eliminated, and the real-time noise is 63.34dB. However, at this time, the protection antenna is used for stealth processing, and the target is deleted by stealth.

[0060] Using the guard antenna sample point signal S after cancellation p (t)' and the ADBF processed and the antenna sample point signal S sum (t) To be kept anonymous.

[0061] The power of the target signal and the clutter signal on the spectrum is counted, and the protection antenna power is the result after superimposing the concealment threshold. The statistical results are shown in the following table:

[0062] According to the statistical results, it can be seen that when the original protection antenna is used for concealment processing, the cooperative target will be concealed and deleted. After the protection antenna is subjected to ASLC processing and then concealed, the clutter is concealed and the target can be sent out normally. The digital array concealment method based on radar protection antenna ASLC disclosed in the above embodiment is effective.

[0063] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A digital array concealment method based on radar protection antenna ASLC, characterized in that: include: Step 1: perform pulse compression and coherence processing on the sampled data of the subarray and the protection antenna, and perform interference detection to determine whether there is an interference signal. If there is an interference signal, proceed to step 2; Step 2: determine the credible flag of the interference angle error. If the interference angle error is not credible and is sidelobe interference, proceed to step 3; Step 3: Eliminate the main lobe signal and select the sample points of the side lobe signal; Step 4: Take the protection antenna as the main channel and each subarray as the auxiliary channel to calculate the optimal weight W of ASLC opt (t); Step 5: cancel the interference signal of the protection antenna sample point to obtain the cancelled protection antenna sample point signal S p (t)'; Step 6: Perform ADBF processing on the sample point signal of the combined antenna to obtain the sample point signal S of the combined antenna after ADBF processing. sum (t), and perform constant false alarm detection; Step 7: Using the guard antenna sample point signal S after cancellation p (t)' and the ADBF processed and the antenna sample point signal S sum (t) To be kept anonymous.

2. The digital array concealment method based on radar protection antenna ASLC according to claim 1 is characterized in that: In step 2, the credible flag of the interference angle error is determined. If the interference angle error is credible as main lobe interference, conventional concealment processing is performed.

3. The digital array concealment method based on radar protection antenna ASLC according to claim 2 is characterized in that: In step 3, the main lobe signal is removed and the sample points of the side lobe signal are selected. Specifically, S p0 (N ri ,N fj )>S sum0 (N ri ,N fj )-S limit The signal is removed and the sample points of the sidelobe signal are selected, where S p0 (N ri ,N fj ) is to protect the antenna signal; S sum0 (N ri ,N fj ) is the antenna signal; S limit To protect the antenna hidden threshold.

4. The digital array concealment method based on radar protection antenna ASLC according to claim 3 is characterized in that: In step 4, the protection antenna is used as the main channel and each subarray is used as the auxiliary channel to calculate the optimal weight W of ASLC. opt (t), specifically: in, S sub (t) is the sub-array sample point signal; is the conjugate transpose of the sub-array sample point signal; To protect the conjugate transpose of the antenna sample point signal.

5. The digital array concealment method based on radar protection antenna ASLC according to claim 4 is characterized in that: In step 5, the interference signal of the protection antenna sample point is cancelled to obtain the cancelled protection antenna sample point signal S p (t)', specifically: in, S p (t) is the protection antenna sample point signal.

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