Method and device for discriminating main and side lobe incident signals of digital array
By generating a non-coherent power synthesis threshold for digital arrays, the problem of limited signal direction finding capability of digital array systems outside the coverage area is solved, and the accurate distinction between main lobe incident and side lobe incident signals is achieved, reducing system resource requirements.
Patent Information
- Application Number
- CN202411339899.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-25
- Publication Date
- 2025-01-21
AI Technical Summary
Existing digital array systems have limited signal direction finding capabilities outside the coverage area, requiring the addition of sidelobe beams or dedicated antennas, which increases system size and cost.
By generating a non-coherent power synthesis threshold for the digital array as a criterion for main lobe incidence and side lobe incidence, the main lobe incidence and side lobe incidence of the digital array can be accurately distinguished, avoiding the synthesis of side lobe-cut beams and the addition of side lobe-cut antennas.
Without adding sidelobe beams and antennas, it achieves accurate differentiation between main lobe and sidelobe incident signals of a digital array, reducing system resource requirements.
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Figure CN119341614A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of digital array signal processing, and more specifically, to a method and device for distinguishing main lobe and side lobe incident signals of a digital array. Background Art
[0002] Current digital arrays usually use multiple digital beams to cover a wide airspace, and then use the amplitude ratio of adjacent digital beams to complete the direction finding function. For a one-dimensional uniform linear digital array, when the array aperture length is constant, the range of the airspace covered is proportional to the number of digital beams. The larger the airspace covered, the more digital beams are needed. However, the number of digital beams is limited by the system processing resources and is often very limited, so the airspace covered is also limited. For sidelobe incident signals outside the coverage airspace, it is impossible to use the amplitude ratio of adjacent beams to perform direction finding; at the same time, for a one-dimensional uniform linear digital array, it can only cover the airspace within ±90° of the normal direction at most. For backlobe incident signals outside ±90°, it is also impossible to use the amplitude ratio of adjacent beams to perform direction finding.
[0003] For incident signals outside the airspace covered by the digital array, they are currently mainly identified by cutting the sidelobe beam; for airspace within ±90° of the normal direction of the digital array that is not covered by the main lobe beam, the sidelobe incident signals are usually identified by synthesizing digital cut sidelobe beams; for backlobe incident signals outside ±90° of the normal direction of the digital array, dedicated cut sidelobe antennas are usually required to identify the backlobe incident signals, and even multiple dedicated cut sidelobe antennas are required to achieve the preparation and identification of the backlobe incident signals. Therefore, whether adding digital cut sidelobe beams or adding dedicated cut sidelobe antennas in processing, the scale and cost of the digital array system will increase, which will limit the application of the digital array system. Summary of the invention
[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method and device for distinguishing the main-lobe and side-lobe incident signals of a digital array. By generating a digital array non-coherent power synthesis threshold as a basis for distinguishing the main-lobe incident and the side-lobe incident, it is possible to accurately distinguish the main-lobe incident signal and the side-lobe incident signal of the digital array without synthesizing a cut-sidelobe beam and adding a cut-sidelobe antenna.
[0005] The object of the present invention is achieved through the following solutions:
[0006] A method for distinguishing main lobe and side lobe incident signals of a digital array comprises the following steps:
[0007] By generating a digital array non-coherent power synthesis threshold as a basis for distinguishing mainlobe incidence and sidelobe incidence, it is possible to accurately distinguish the mainlobe incidence signal and sidelobe incidence signal of the digital array without synthesizing a cut-sidelobe beam and adding a cut-sidelobe antenna.
[0008] Furthermore, the method generates a digital array non-coherent power synthesis threshold as a basis for distinguishing main lobe incidence and side lobe incidence, and can accurately distinguish the main lobe incidence signal and the side lobe incidence signal of the digital array without synthesizing a cut side lobe beam and adding a cut side lobe antenna, which specifically includes the following sub-steps:
[0009] Step 1: using a digital down-conversion group (1) to perform digital down-conversion processing on N digital signals outputted by a one-dimensional uniform linear digital array, converting the N real signals into N complex signals, and at the same time converting the radio frequency down to zero intermediate frequency;
[0010] Step 2: low-pass filtering is performed on the N zero-IF complex signals output by the digital down-conversion group (1) using a low-pass filter group (2). On the one hand, the image signal is filtered out, and on the other hand, the in-band signal-to-noise ratio can be improved by filtering. N is an integer.
[0011] Step 3: using a digital multi-beam forming unit (3) to perform multiple digital beam forming on the N zero intermediate frequency complex signals output by the low-pass filter group (2);
[0012] Step 4: Use the peak search unit (4) to search the K digital beams P (θ k ) performs peak search processing to obtain the peak value of the maximum beam;
[0013] Step 5: using a non-coherent power synthesis unit (5) to perform modulus sampling on the N-channel zero intermediate frequency complex signals output by the low-pass filter group (2), and then performing non-coherent power synthesis on the N-channel modulus values;
[0014] Step 6: Generate a threshold for non-coherent power synthesis using a threshold generation unit (6);
[0015] Step 7: Use the main lobe and side lobe distinguishing unit (7) to distinguish the main lobe incident signal and the side lobe incident signal. When the peak value P of the maximum beam is max ≥P th When , it is judged as the main lobe incident signal; when the peak value P of the maximum beam is max <P th When , it is judged as a sidelobe incident signal.
[0016] Further, in step 1, in the digital down-conversion process, the down-conversion formula used is: Where j is the number of array elements, ranging from 1 to N, n is the number of sampling points, f is the RF frequency, and ts is the sampling period, y j (n) is the complex signal generated by down-converting the real signal output by the j-th array element, x j (n) is the real signal output by the jth array element.
[0017] Further, in step 2, in the low-pass filtering, the low-pass filter adopts a FIR filter, and the filtering formula is:
[0018] Where P is the order of the filter, z j (n) is the complex signal generated by the j-th array element after down-conversion filtering, m is a coefficient from 0 to P-1, P is the order of the filter, and w is the generated filter coefficient.
[0019] Further, in step 3, the digital beamforming method is:
[0020] Where d is the array element spacing, θ k is the pointing angle of K digital beams, c is the speed of light 3e 8 , P(θ k ) is the digital beam pointing θ k The directional pattern function, z j is the complex signal generated by the j-th array element after down-conversion filtering.
[0021] Furthermore, in step 4, the peak search formula is: max =max(P(θ k )), P max is the maximum peak value of all digital beams.
[0022] Furthermore, in step 5, the non-coherent power synthesis formula is: P abs is the non-phase difference power synthesis value.
[0023] Furthermore, in step 6, the threshold generation formula is: th =k coe *P abs , where k coe is the floating coefficient factor.
[0024] Furthermore, the value of the floating coefficient factor includes 0.5.
[0025] A device for distinguishing main-lobe and side-lobe incident signals of a digital array comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is loaded by the processor, any of the above methods is executed.
[0026] The beneficial effects of the present invention include:
[0027] The method of the present invention can accurately distinguish the main lobe incident signal and the side lobe incident signal of the digital array without synthesizing the cut side lobe beam and adding the cut side lobe antenna, and can greatly reduce the cut side lobe resources of the digital array. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0029] Figure 1 A schematic diagram of a method according to an embodiment of the present invention;
[0030] Figure 2 In the embodiment of the present invention, the non-coherent accumulation synthesis threshold is used as the basis for distinguishing the main lobe (within ±15°) and the side lobe (outside ±15°);
[0031] Figure 3 In the embodiment of the present invention, the main lobe (0°) incident signal can be identified based on the non-coherent synthesis power threshold;
[0032] Figure 4 In the embodiment of the present invention, the side lobe (60°) incident signal can be identified based on the non-coherent synthesis power threshold;
[0033] In the figure, 1-digital down-conversion group, 2-low-pass filter group, 3-digital multi-beam forming unit, 4-peak search unit, 5-non-coherent power synthesis unit, 6-peak search unit, 7-main-side lobe discrimination unit. DETAILED DESCRIPTION
[0034] All features disclosed in all embodiments in this specification, or steps in all methods or processes implicitly disclosed, except for mutually exclusive features and / or steps, can be combined and / or expanded or replaced in any manner.
[0035] The specific implementation process of the present invention is as follows:
[0036] Step 1: Digital down-conversion group 1 performs digital down-conversion processing on the N digital signals output by the one-dimensional uniform linear digital array, converting the N real signals into N complex signals, and at the same time converting the RF frequency down to zero intermediate frequency; the down-conversion formula is: Where j is the number of array elements, ranging from 1 to N, n is the number of sampling points, f is the RF frequency, and t s is the sampling period.
[0037] Step 2: Low-pass filter group 2 mainly performs low-pass filtering on the N-channel zero intermediate frequency complex signals output by digital down-conversion group 1. On the one hand, it filters the image signal, and on the other hand, it can improve the in-band signal-to-noise ratio through filtering. The low-pass filter uses an FIR filter, the filter passband bandwidth is B, which is generally larger than the signal bandwidth, the filter stopband bandwidth is 2B, the out-of-band suppression DL, the generated filter coefficient is w, and the filtering formula is: Where P is the order of the filter.
[0038] Step 3: The digital multi-beam forming unit 3 mainly performs multiple digital beamforming on the N-channel zero intermediate frequency complex signals output by the low-pass filter group 2. The digital beamforming method is: Where d is the array element spacing, θ k is the pointing angle of K digital beams, c is the speed of light 3e 8 .
[0039] Step 4: The peak search unit 4 mainly searches the K digital beams P(θ k ) to perform peak search processing to obtain the peak value of the maximum beam. The peak search formula is: P max =max(P(θ k )).
[0040] Step 5: The non-coherent power synthesis unit 5 mainly extracts the modulus value of the N-channel zero intermediate frequency complex signals output by the low-pass filter group 2, and then performs non-coherent power synthesis on the N-channel modulus values. The non-coherent power synthesis formula is:
[0041] Step 6: The threshold generation unit 6 mainly generates the threshold of non-coherent power synthesis. The threshold generation formula is: P th =k coe *P abs , where k coe It is the floating coefficient factor, which is usually 0.5.
[0042] Step 7: The main lobe and side lobe distinguishing unit 7 distinguishes the main lobe incident signal and the side lobe incident signal. When the peak value P of the maximum beam max ≥P th When , it is judged as the main lobe incident signal; when the peak value P of the maximum beam is max <P th When , it is judged as a sidelobe incident signal.
[0043] In other embodiments, the device of the present invention includes a digital down-conversion group 1, a low-pass filter group 2, a digital multi-beam forming unit 3, a peak search unit 4, a non-coherent power synthesis unit 5, a threshold generation unit 6, and a main-side lobe discrimination unit 7. The specific components are as follows: Figure 1 As shown, a certain system is used as an example to illustrate:
[0044] 1. The antenna array is a 16-element one-dimensional uniform linear array with an element spacing d of 15 mm. The frequency is a continuous wave signal of 8.1 GHz. The digital down-conversion group 1 performs digital down-conversion processing on the 16 digital signals output by the one-dimensional uniform linear digital array, converting the 16 real signals into 16 complex signals and converting the RF frequency into zero intermediate frequency at the same time. The down-conversion formula is: Where j is the number of array elements, ranging from 1 to 16, n is the number of sampling points, f is the RF frequency 8.1 GHz, t s The sampling period is 500ps.
[0045] 2. Low-pass filter group 2 mainly performs low-pass filtering on the 16 zero-IF complex signals output by digital down-conversion group 1. On the one hand, it filters the image signal, and on the other hand, it can improve the in-band signal-to-noise ratio through filtering. The low-pass filter uses an FIR filter with a passband bandwidth of 20MHz, a stopband bandwidth of 40MHz, and an out-of-band suppression of 40dB. The generated filter coefficient is w, and the filtering formula is: Where 142 is the order of the filter.
[0046] 3. The digital multi-beam forming unit 3 mainly performs multiple digital beam forming on the 16 zero intermediate frequency complex signals output by the low-pass filter group 2. The digital beam forming method is: Where d is the array element spacing of 15 mm, θ k are the pointing angles of the five digital beams, pointing to -15°, -7.5°, 0°, 7.5°, and 15° respectively, and c is the speed of light 3e 8 ; The effect of multiple digital beamforming is as follows Figure 2 shown.
[0047] 4. The peak search unit 4 mainly searches for the five digital beams P(θ k ) to perform peak search processing to obtain the peak value of the maximum beam. The peak search formula is: P max =max(P(θ k )).
[0048] 5. The non-coherent power synthesis unit 5 mainly extracts the modulus value of the 16-channel zero intermediate frequency complex signal output by the low-pass filter group 2, and then performs non-coherent power synthesis on the 16-channel modulus value. The non-coherent power synthesis formula is:
[0049] 6. The threshold generation unit 6 mainly generates the threshold of non-coherent power synthesis. The threshold generation formula is: P th =0.5*P abs , the non-coherent power synthesis threshold generation effect is as follows Figure 2 shown.
[0050] 7. The main lobe and side lobe distinguishing unit 7 distinguishes the main lobe incident signal and the side lobe incident signal. When the peak value P of the maximum beam max ≥P th When , it is judged as the main lobe incident signal; when the peak value P of the maximum beam is max <P th When , it is judged as the side lobe incident signal, and the main lobe incident signal judgment effect is as follows Figure 3 As shown in the figure, the discrimination effect of the sidelobe incident signal is as follows: Figure 4 shown.
[0051] It should be noted that within the scope of protection defined in the claims of the present invention, the following embodiments can be combined and / or expanded or replaced in any logical way from the above specific implementation methods, such as disclosed technical principles, disclosed technical features or implicitly disclosed technical features.
[0052] Example 1
[0053] A method for distinguishing main lobe and side lobe incident signals of a digital array comprises the following steps:
[0054] By generating a digital array non-coherent power synthesis threshold as a basis for distinguishing mainlobe incidence and sidelobe incidence, it is possible to accurately distinguish the mainlobe incidence signal and sidelobe incidence signal of the digital array without synthesizing a cut-sidelobe beam and adding a cut-sidelobe antenna.
[0055] Example 2
[0056] On the basis of Example 1, the digital array non-coherent power synthesis threshold is generated as the basis for distinguishing the main lobe incident and the side lobe incident, and the main lobe incident signal and the side lobe incident signal of the digital array can be accurately distinguished without synthesizing the cut side lobe beam and adding the cut side lobe antenna, which specifically includes the following sub-steps:
[0057] Step 1: using a digital down-conversion group (1) to perform digital down-conversion processing on N digital signals outputted by a one-dimensional uniform linear digital array, converting the N real signals into N complex signals, and at the same time converting the radio frequency down to zero intermediate frequency;
[0058] Step 2: low-pass filtering is performed on the N zero-IF complex signals output by the digital down-conversion group (1) using a low-pass filter group (2). On the one hand, the image signal is filtered out, and on the other hand, the in-band signal-to-noise ratio can be improved by filtering. N is an integer.
[0059] Step 3: using a digital multi-beam forming unit (3) to perform multiple digital beam forming on the N zero intermediate frequency complex signals output by the low-pass filter group (2);
[0060] Step 4: Use the peak search unit (4) to search the K digital beams P (θ k ) performs peak search processing to obtain the peak value of the maximum beam;
[0061] Step 5: using a non-coherent power synthesis unit (5) to perform modulus sampling on the N-channel zero intermediate frequency complex signals output by the low-pass filter group (2), and then performing non-coherent power synthesis on the N-channel modulus values;
[0062] Step 6: Generate a threshold for non-coherent power synthesis using a threshold generation unit (6);
[0063] Step 7: Use the main lobe and side lobe distinguishing unit (7) to distinguish the main lobe incident signal and the side lobe incident signal. When the peak value P of the maximum beam is max ≥P th When , it is judged as the main lobe incident signal; when the peak value P of the maximum beam is max <P th When , it is judged as a sidelobe incident signal.
[0064] Example 3
[0065] On the basis of Embodiment 2, in step 1, in the digital down-conversion process, the down-conversion formula used is: Where j is the number of array elements, ranging from 1 to N, n is the number of sampling points, f is the RF frequency, and t s is the sampling period, y j (n) is the complex signal generated by down-converting the real signal output by the j-th array element, x j (n) is the real signal output by the jth array element.
[0066] Example 4
[0067] On the basis of Embodiment 3, in step 2, in the low-pass filtering, the low-pass filter adopts a FIR filter, and the filtering formula is:
[0068] Where P is the order of the filter, z j (n) is the complex signal generated by the j-th array element after down-conversion filtering, m is a coefficient from 0 to P-1, P is the order of the filter, and w is the generated filter coefficient.
[0069] Example 5
[0070] On the basis of Embodiment 4, in step 3, the digital beamforming method is:
[0071] Where d is the array element spacing, θ k is the pointing angle of K digital beams, c is the speed of light 3e 8 , P(θk ) is the digital beam pointing θ k The directional pattern function, z j is the complex signal generated by the j-th array element after down-conversion filtering.
[0072] Example 6
[0073] Based on Example 5, in step 4, the peak search formula is: max =max(P(θ k )), P max is the maximum peak value of all digital beams.
[0074] Example 7
[0075] On the basis of Example 6, in step 5, the non-coherent power synthesis formula is: P abs is the non-phase difference power synthesis value.
[0076] Example 8
[0077] Based on Example 7, in step 6, the threshold generation formula is: th =k coe *P abs , where k coe is the floating coefficient factor.
[0078] Example 9
[0079] Based on Example 8, the value of the floating coefficient factor includes 0.5.
[0080] Example 10
[0081] A device for distinguishing main-lobe and side-lobe incident signals of a digital array comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is loaded by the processor, a method as described in any one of Embodiments 1 to 9 is executed.
[0082] The units involved in the embodiments of the present invention may be implemented by software or hardware, and the units described may also be arranged in a processor. The names of these units do not, in some cases, limit the units themselves.
[0083] According to one aspect of an embodiment of the present invention, a computer program product or a computer program is provided, the computer program product or the computer program includes a computer instruction, and the computer instruction is stored in a computer-readable storage medium. A processor of a computer device reads the computer instruction from the computer-readable storage medium, and the processor executes the computer instruction, so that the computer device executes the method provided in the above various optional implementations.
[0084] As another aspect, an embodiment of the present invention further provides a computer-readable medium, which may be included in the electronic device described in the above embodiment; or may exist independently without being assembled into the electronic device. The above computer-readable medium carries one or more programs, and when the above one or more programs are executed by an electronic device, the electronic device implements the method described in the above embodiment.
Claims
1. A method for distinguishing main lobe and side lobe incident signals of a digital array, characterized in that: The following steps are involved: By generating a digital array non-coherent power synthesis threshold as a basis for distinguishing mainlobe incidence and sidelobe incidence, it is possible to accurately distinguish the mainlobe incidence signal and sidelobe incidence signal of the digital array without synthesizing a cut-sidelobe beam and adding a cut-sidelobe antenna.
2. The method for distinguishing main lobe and side lobe incident signals of a digital array according to claim 1, characterized in that: The method generates a digital array non-coherent power synthesis threshold as a basis for distinguishing main lobe incidence and side lobe incidence, and can accurately distinguish the main lobe incidence signal and the side lobe incidence signal of the digital array without synthesizing a cut side lobe beam and adding a cut side lobe antenna, and specifically includes the following sub-steps: Step 1: using a digital down-conversion group (1) to perform digital down-conversion processing on N digital signals outputted by a one-dimensional uniform linear digital array, converting the N real signals into N complex signals, and at the same time converting the radio frequency down to zero intermediate frequency; Step 2: low-pass filtering is performed on the N zero-IF complex signals output by the digital down-conversion group (1) using a low-pass filter group (2). On the one hand, the image signal is filtered out, and on the other hand, the in-band signal-to-noise ratio can be improved by filtering. N is an integer. Step 3: using a digital multi-beam forming unit (3) to perform multiple digital beam forming on the N zero intermediate frequency complex signals output by the low-pass filter group (2); Step 4: Use the peak search unit (4) to search the K digital beams P (θ k ) performs peak search processing to obtain the peak value of the maximum beam; Step 5: using a non-coherent power synthesis unit (5) to perform modulus sampling on the N-channel zero intermediate frequency complex signals output by the low-pass filter group (2), and then performing non-coherent power synthesis on the N-channel modulus values; Step 6: Generate a threshold for non-coherent power synthesis using a threshold generation unit (6); Step 7: Use the main lobe and side lobe distinguishing unit (7) to distinguish the main lobe incident signal and the side lobe incident signal. When the peak value P of the maximum beam is max ≥P th When , it is judged as the main lobe incident signal; when the peak value P of the maximum beam is max <P th When , it is judged as a sidelobe incident signal.
3. The method for distinguishing main lobe and side lobe incident signals of a digital array according to claim 2, characterized in that: In step 1, in the digital down-conversion process, the down-conversion formula used is: Where j is the number of array elements, ranging from 1 to N, n is the number of sampling points, f is the RF frequency, and t s is the sampling period, y j (n) is the complex signal generated by down-converting the real signal output by the j-th array element, x j (n) is the real signal output by the jth array element.
4. The method for distinguishing main lobe and side lobe incident signals of a digital array according to claim 3, characterized in that: In step 2, in the low-pass filtering, the low-pass filter adopts a FIR filter, and the filtering formula is: Where P is the order of the filter, z j (n) is the complex signal generated by the j-th array element after down-conversion filtering, m is a coefficient from 0 to P-1, P is the order of the filter, and w is the generated filter coefficient.
5. The method for determining the main lobe and side lobe incident signals of a digital array according to claim 4, characterized in that: In step 3, the digital beamforming method is: Where d is the array element spacing, θ k is the pointing angle of K digital beams, c is the speed of light 3e 8 , P(θ k ) is the digital beam pointing θ k The directional pattern function, z j is the complex signal generated by the j-th array element after down-conversion filtering.
6. The method for determining the main lobe and side lobe incident signals of a digital array according to claim 5, characterized in that: In step 4, the peak search formula is: P max =max(P(θ k )).P max is the maximum peak value of all digital beams.
7. The method for distinguishing main lobe and side lobe incident signals of a digital array according to claim 6, characterized in that: In step 5, the non-coherent power synthesis formula is: P abs is the non-phase difference power synthesis value.
8. The method for distinguishing main lobe and side lobe incident signals of a digital array according to claim 7, characterized in that: In step 6, the threshold generation formula is: P th =k coe *P abs , where k coe is the floating coefficient factor.
9. The method for distinguishing main lobe and side lobe incident signals of a digital array according to claim 8, characterized in that: The value of the floating coefficient factor includes 0.
5.
10. A device for distinguishing main lobe and side lobe incident signals of a digital array, characterized in that: The method comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is loaded by the processor, the method according to any one of claims 1 to 9 is executed.