Single-sided interferometer linear array azimuth anonymous shadow processing method

Abstract

The invention relates to a single-sided interferometer linear array azimuth anonymous shadow processing method. The method comprises the following steps: constructing an asymmetric interferometer array; designing an array amplitude inconsistency threshold; and based on the array amplitude inconsistency threshold, determining the area where the radiation source is located and performing corresponding processing. Compared with the prior art, on one hand, the antenna mounting plate is designed to be in a non-uniform convex shape, and the wave absorbing material is asymmetrically attached to the antenna mounting plate, so that the directional diagram characteristics of a shadow hiding area can be changed under the condition that additional shadow hiding antenna units and processing channels are not increased; on the other hand, different array amplitude inconsistency threshold criteria are designed in the direction finding area and the hidden image area, so that efficient and reliable orientation hidden image detection is achieved, accurate direction finding of the radiation source signals in the direction finding area is achieved, and meanwhile the radiation source signals in the hidden image area are removed.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic signal receiving and processing technology, and in particular to a method for azimuth masking processing of a single-sided interferometer linear array. Background Technology

[0002] In the field of passive direction finding, compared with amplitude comparison direction finding, multi-beam direction finding, and time difference direction finding methods, interferometric direction finding is favored because of its advantages of small equipment size and high direction finding accuracy. Interferometric linear arrays are used in direction finding systems to estimate the azimuth angle of a signal source. The principle is based on the phase difference measurement of signals received by multiple antennas. A linear array is usually composed of multiple equally spaced antenna elements. When a plane wave signal is incident, there is a phase difference between the signals received by different antennas. This phase difference is related to the incident direction (azimuth angle) of the signal. By analyzing these phase differences, the azimuth of the signal source can be calculated.

[0003] Single-sided interferometer linear arrays receive signals through a single-sided linear array antenna and use phase differences to calculate the target azimuth or distance. The signal direction is determined by analyzing the phase differences between different antenna elements. Its core advantages lie in its high precision, high dynamic range, compact structure, and strong anti-interference capability, making it particularly suitable for scenarios requiring rapid and high-precision measurements. Currently, single-sided interferometer linear arrays are widely used in passive direction finding. However, single-sided linear interferometer arrays have two problems when performing azimuth measurements: first, when the signal incident angle is large, direction finding errors can occur due to poor phase consistency of the antennas; second, when the signal is incident backwards on the array, there is a situation where the front and back are not distinguished, leading to the measurement of the forward azimuth.

[0004] In complex electromagnetic environments, low-cost, miniaturized direction-finding equipment using single-sided interferometer linear arrays is limited by its size and cannot effectively suppress or eliminate incident signals in concealed regions (large angle and back-facing regions). This leads to the erroneous measurement of the angle of the incident signal in the concealed region into the effective direction-finding region, forming false target signals. To ensure accurate azimuth measurement of the interferometer array within the direction-finding region, and to suppress or eliminate large-angle and back-facing incident signals, concealment processing is usually required to avoid false direction-finding signals and improve target detection performance. In existing technologies, concealment processing for large-angle and back-facing incident signals from unknown radiation sources is mainly achieved by adding concealed antenna elements and receiving processing channels to the sides and back. When the signal received by the concealed antenna element exceeds a threshold, it is judged as a cluttered azimuth signal and no further processing is performed. This method can effectively reduce the influence of cluttered signals and improve the detection performance of the equipment, but it requires additional software and hardware resources, is bulky and costly, and has certain limitations on the installation platform, thus greatly limiting its application in low-cost, miniaturized equipment. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a single-sided interferometer linear array azimuth masking method that can effectively suppress unknown radiation sources in a specific azimuth without increasing the masking antenna and receiving channel.

[0006] The objective of this invention can be achieved through the following technical solution: a method for azimuth masking of a single-sided interferometer linear array, comprising the following steps: S1. Construct an asymmetric interferometer array; S2, Design array amplitude inconsistency threshold; S3. Based on the array amplitude inconsistency threshold, determine the region where the radiation source is located and perform corresponding processing.

[0007] Further, step S1 includes the following steps: S11. Install multiple antenna elements on the antenna mounting plate; S12. Retain the forward direction finding area of ​​each antenna element, set other directions as the concealment area, and asymmetrically attach absorbing material around each antenna element in other directions.

[0008] Furthermore, in step S11, multiple antenna elements are respectively arranged at both ends and in the middle area of ​​the antenna mounting plate.

[0009] Furthermore, step S12 specifically involves ensuring that the signal incident window of the forward direction finding area of ​​each antenna element is completely unobstructed, and asymmetrically attaching absorbing material to the aperture, sides, and rear of each antenna element.

[0010] Furthermore, the signal incident window angle range of the forward direction finding region is -45° to 45°.

[0011] Furthermore, the height of the absorbing material is higher than the aperture height of the antenna element.

[0012] Furthermore, the antenna elements at both ends of the antenna mounting plate are completely wrapped with absorbing material, and the middle area of ​​the antenna mounting plate has multiple non-uniform protrusions on the side facing away from the antenna elements.

[0013] Further, step S2 specifically involves measuring the amplitude direction between each antenna element in the anechoic region and the direction-finding region of the asymmetric interferometer array in a microwave anechoic chamber. Figure 1 Consistency is used to design an array amplitude inconsistency threshold.

[0014] Further, step S2 includes the following steps: S21. Measure the omnidirectional radiation pattern of each antenna element in an asymmetric interferometer array in a microwave anechoic chamber; S22. Select one antenna element in the asymmetric interferometer array as the reference antenna element, calculate the amplitude difference between the reference antenna element and other antenna elements in the direction finding region and the amplitude difference in the shadow region, and design the tolerance in combination with the specific antenna type to determine the array amplitude inconsistency threshold.

[0015] Furthermore, the specific process of step S3 is as follows: The amplitude inconsistency between the reference antenna element and other antenna elements is calculated separately to obtain multiple sets of inconsistency values. These multiple sets of inconsistency values ​​are compared with the array amplitude inconsistency threshold. If the value is greater than the threshold, the logic value is 1; otherwise, the logic value is 0. The multiple logical values ​​obtained from the comparison are ORed. If the logical OR value of the wave from a certain direction is 1, the radiation source is determined to be located in the shadow area, the relevant data is discarded, and no further processing is performed. If the logical OR value of the incoming wave signal in a certain direction is 0, the radiation source location is determined to be the direction finding area, and the interferometer array processing continues.

[0016] Compared with the prior art, the present invention has the following advantages: This invention first constructs an asymmetric interferometer array, then designs an array amplitude inconsistency threshold, and then determines the region where the radiation source is located and performs corresponding processing based on the array amplitude inconsistency threshold. This realizes a low-cost and high-efficiency method for azimuth masking of a single-sided interferometer linear array, which can solve the problem of direction finding error of incident signal in the masking region of a single-sided interferometer linear array without adding extra hardware.

[0017] This invention determines the forward direction-finding region based on an interferometer array, while simultaneously designating other directions as concealed regions. While maintaining a completely unobstructed signal incident window in the forward direction-finding region, absorbing materials are asymmetrically attached to the aperture, sides, and rear of the array antenna elements. A non-uniform protrusion design is also incorporated into the antenna mounting plate. This ensures the amplitude and phase consistency of the antennas in the direction-finding region while disrupting the amplitude and phase consistency between antennas in the concealed regions. This invention solves the problem at the design level, utilizing only the antenna elements and receiving channels of the single-sided interferometer linear array itself. By designing the shape of the antenna mounting plate and the absorbing material, the radiation pattern characteristics of the concealed regions are altered, eliminating the need for additional concealed antenna elements and processing channels, effectively reducing equipment size and cost.

[0018] This invention uses the gain difference between antenna elements as a benchmark. By designing different array amplitude inconsistency threshold criteria in the direction finding region and the azimuth occlusion region, it can achieve efficient and reliable azimuth occlusion detection. While ensuring non-destructive and high-precision direction finding in the direction finding region, it effectively solves the problem of false azimuth alarms caused by large incident angles and backward incident signals in the direction finding of single-sided linear array interferometers. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the method flow of the present invention; Figure 2 This is a schematic diagram illustrating the application process of an example. Figure 3 This is a side view schematic diagram of the asymmetric interferometer array in the embodiment; Figure 4 This is a top-view schematic diagram of the asymmetric interferometer array in the embodiment; Figure 5 This is a three-dimensional perspective view of the asymmetric interferometer array in the embodiment; Figure 6 This is a schematic diagram illustrating the threshold range for antenna array amplitude inconsistency and the threshold design in this embodiment. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0021] Example like Figure 1 As shown, a method for azimuth masking of a single-sided interferometer linear array includes the following steps: S1. Construct an asymmetric interferometer array; S2, Design array amplitude inconsistency threshold; S3. Based on the array amplitude inconsistency threshold, determine the region where the radiation source is located and perform corresponding processing.

[0022] In step S1, the forward direction finding area is determined based on the interferometer array, while other directions are set as shadow areas. While ensuring that the signal incident window of the forward direction finding area is completely unobstructed, absorbing materials are asymmetrically attached to the aperture, sides and back of the array antenna elements, and the antenna mounting plate is designed with non-uniform protrusions. This ensures the amplitude and phase consistency of the antennas in the direction finding area while disrupting the amplitude and phase consistency of the antennas in the shadow areas.

[0023] In step S2, specifically, the amplitude direction between each antenna element in the anechoic region and the direction-finding region is measured in a microwave anechoic chamber. Figure 1 To ensure consistency, the amplitude difference between the reference antenna element and other antenna elements in the direction-finding region and in the shadow region are calculated respectively. Tolerances are designed in combination with factors such as specific antenna type, and the array amplitude inconsistency threshold is determined.

[0024] In step S3, the amplitude inconsistency between the reference antenna element and other antenna elements is calculated separately, resulting in multiple sets of inconsistency values. These values ​​are then compared with the array amplitude inconsistency threshold. Values ​​greater than the threshold are assigned a logical value of 1, while values ​​less than the threshold are assigned a logical value of 0. The obtained logical values ​​are then ORed. If the logical OR value of the incoming wave from a certain azimuth is 1, the radiation source is determined to be located in the shadow region, and the relevant data is discarded without further processing. If the logical OR value of the incoming wave signal from a certain azimuth is 0, the radiation source is determined to be located in the direction-finding region, and the interferometer array processing continues.

[0025] This embodiment applies the above-described solution, such as Figure 2 As shown, the main processes include: Step 1, Design of asymmetric interferometer array; like Figures 3-5 As shown, an asymmetric interferometer array is designed, with multiple antenna elements mounted on an antenna mounting plate. Each antenna element retains complete transmission of the signal incident window in the forward direction-finding region (typically ±45°) or the direction-finding space on one side. Absorbing material is attached to all other directions around the antenna elements, with the absorbing material slightly higher than the antenna aperture. The antenna elements at both ends of the mounting plate are completely encased in absorbing material, while the mounting plate in the middle region features a non-uniform raised structure. Through the asymmetric design of the absorbing material and the antenna mounting plate, the radiation pattern of each antenna element in the array can be altered, ensuring the direction of transmission in the forward direction-finding region... Figure 1 Consistency, and disruption of the orientation of the occlusion regions (side lobes and tail lobes) between antenna elements. Figure 1 To the point of being responsive.

[0026] Step 2, design the array amplitude inconsistency threshold; In a microwave anechoic chamber, the omnidirectional radiation pattern of each antenna element in the antenna array is measured using the radiation method. Taking one antenna element as a reference, the amplitude difference curves of the other three antenna elements and the reference antenna element in the direction finding region and the shadowing region are obtained. Based on the three sets of amplitude difference curves, the array amplitude inconsistency threshold is determined according to the design tolerance and shadowing criteria for different regions.

[0027] Figure 6 The diagram shows the amplitude inconsistency threshold between other antenna elements and the reference antenna element. When the signal is in the direction finding region, the threshold value depends on the individual differences between the antenna elements. Usually, the amplitude consistency is very good, so the amplitude difference of the three sets of curves is required to be consistent. When the signal is in the shadow region, due to the asymmetric design, the amplitude difference of the received signal between the antenna elements becomes larger, and the amplitude consistency of at least two antennas deteriorates.

[0028] Step 3, stealth analysis and processing; The amplitude inconsistency between the reference antenna element and other antenna elements is calculated separately, resulting in multiple sets of inconsistency values. These values ​​are then compared with amplitude inconsistency thresholds. Values ​​greater than the threshold are assigned a logical value of 1, while values ​​less than the threshold are assigned a logical value of 0. The obtained logical values ​​are then ORed. If the logical OR value of the incoming wave in a certain azimuth is 1, the radiation source is determined to be located in the shadowed region, and the relevant data is discarded without further processing. If the logical OR value of the incoming wave signal in a certain azimuth is 0, the radiation source is determined to be located in the direction-finding region, and the interferometer array continues processing. This achieves accurate direction finding of radiation source signals within the direction-finding region while simultaneously eliminating radiation source signals in the shadowed region, thus improving detection performance.

[0029] In summary, this solution proposes a low-cost and high-efficiency method for azimuth masking of single-sided interferometer linear arrays. Without adding additional hardware masking channels, it innovatively proposes a method for achieving azimuth masking at the array design level. Addressing the problem that low-cost, miniaturized devices cannot effectively suppress or eliminate large-angle and back-incident signals in complex electromagnetic environments using hardware masking methods, leading to erroneous measurement of the incident signal angle within the masked area and the formation of false signals, this solution effectively solves the direction-finding error problem of incident signals in single-sided interferometer linear arrays within the masked area without adding extra hardware. It has advantages such as small size and low cost, and can be widely applied to various types of platforms.

Claims

1. A method for processing monostatic interferometer linear array azimuth shadowing, characterized in that, The method comprises the following steps: S1, constructing an asymmetric interferometer array; S2, designing an array amplitude inconsistency threshold; S3, determining the region where the radiation source is located based on the array amplitude inconsistency threshold and performing corresponding processing.

2. The method according to claim 1, wherein, The step S1 comprises the following steps: S11, installing multiple antenna units on an antenna mounting plate; S12, reserving a forward direction-finding region of each antenna unit, setting other directions as shadow regions, and asymmetrically attaching wave-absorbing materials to the periphery of each antenna unit.

3. The method of claim 2, wherein, The multiple antenna units in the step S11 are respectively arranged at both ends and the middle region of the antenna mounting plate.

4. The method of claim 3, wherein, The step S12 specifically reserves a signal incident window of the forward direction-finding region of each antenna unit to be completely unobstructed, and asymmetrically attaches wave-absorbing materials to the front face, side face and back face of each antenna unit.

5. The method of claim 4, wherein, The signal incident window of the forward direction-finding region has an angle range of -45°~45°.

6. The method of claim 4, wherein, The height of the wave-absorbing material is higher than the height of the front face of the antenna unit.

7. The method of claim 4, wherein the method further comprises: The antenna units at both ends of the antenna mounting plate are completely wrapped by the wave-absorbing material, and the side of the middle region of the antenna mounting plate away from the antenna units is provided with multiple non-uniform protruding structures.

8. The method of claim 1, wherein, The step S2 specifically measures the amplitude pattern consistency between each antenna unit in the shadow region and the direction-finding region in the asymmetric interferometer array in a microwave darkroom, to design the array amplitude inconsistency threshold.

9. The method of claim 8, wherein, The step S2 comprises the following steps: S21, measuring the omnidirectional pattern of each antenna unit in the asymmetric interferometer array in a microwave darkroom; S22, selecting one antenna unit in the asymmetric interferometer array as a reference antenna unit, respectively calculating the amplitude difference of the reference antenna unit and other antenna units in the direction-finding region and the amplitude difference in the shadow region, and combining the specific antenna type design tolerance to determine the array amplitude inconsistency threshold.

10. The method of claim 9, wherein, The specific process of the step S3 is as follows: The amplitude inconsistency of the reference antenna unit and other antenna units is calculated to obtain multiple inconsistency values, the multiple inconsistency values are compared with the array amplitude inconsistency threshold respectively, if greater than the threshold, the logic value is 1, and if less than the threshold, the logic value is 0; The multiple logic values obtained by comparison are subjected to or processing, if the logic or value of a certain direction of arrival is 1, it is determined that the radiation source is located in the shadow region, the related data is excluded, and the processing is not continued; If the logic or value of a certain direction of arrival signal is 0, it is determined that the radiation source is located in the direction-finding region, and the interferometer array processing is continued.

Images