Interferometer direction finding result quality assessment method, device and medium

Abstract

The application discloses an interferometer direction finding result quality evaluation method, equipment and medium, wherein the evaluation method comprises the following steps: performing reverse calculation on the theoretical phase difference by using the azimuth of direction finding and the baseline length; then, based on the difference between the real measurement phase difference and the theoretical phase difference of each baseline, calculating the threshold value by using the signal-to-noise ratio and the maximum phase difference tolerance during the design of the antenna baseline; then, obtaining the direction finding result quality evaluation of each baseline by using the relationship between the difference and the threshold value; finally, performing result fusion on the direction finding result quality evaluation data of each baseline by multiplication, so as to obtain the final interferometer direction finding result quality evaluation. The direction finding result quality evaluation data can be used to evaluate whether the interferometer direction finding result is reliable, so as to prevent the problem of performance decline of the equipment due to the direction finding error.

Description

Technical Field

[0001] This invention relates to the field of direction finding technology, and in particular to a method, equipment and medium for evaluating the quality of interferometer direction finding results. Background Technology

[0002] Interferometer direction finding systems utilize the phase difference between incoming waves received by multi-baseline antennas for direction finding. They have advantages such as high direction finding sensitivity, high direction finding accuracy, fast direction finding speed, strong signal adaptability, strong anti-multipath capability, and low equipment complexity. They are widely used in fields such as radio monitoring, electronic reconnaissance, and passive positioning.

[0003] However, judging from the current application of interferometers, their actual direction-finding performance is usually far less than the theoretical performance. In some cases, direction-finding errors frequently occur due to unambiguity issues. The accuracy of the phase difference directly affects the accuracy of direction finding (see: Phase Error Analysis of Direction Finding Systems Based on Phase Interferometers, Wu Baodong & Chen Shu, 2008). In current practical interferometer direction-finding systems, the accuracy of the phase difference is mainly affected by the following factors: 1) the tolerance of unambiguity to phase errors during antenna baseline design; 2) the influence of signal-to-noise ratio, as thermal noise can cause phase difference fluctuations; 3) the influence of system correction errors, as each antenna receiving channel is not ideal, and phase difference correction between channels is required in practical interferometer systems. If the correction is not ideal, some inherent deviations will remain between channels; 4) in complex electromagnetic environments, due to multipath superposition, creeping waves on the equipment, and coupling between antennas.

[0004] Of these factors, the first one is considered at the beginning of the equipment design, while the phase difference caused by the latter three factors may lead to unambiguity errors and thus direction finding errors if it exceeds the tolerance of the baseline design. Summary of the Invention

[0005] To address the aforementioned issues, this invention proposes a method, device, and medium for evaluating the quality of interferometer direction finding results. This method assesses the reliability of interferometer direction finding results, thereby preventing performance degradation due to direction finding errors.

[0006] The technical solution adopted in this invention is as follows:

[0007] A method for evaluating the quality of interferometer direction finding results includes the following steps:

[0008] S1. Calculate the theoretical phase difference in reverse using the azimuth and baseline length of the direction finding;

[0009] S2. Based on the difference between the actual measured phase difference and the theoretical phase difference of each baseline, the threshold value is calculated through the signal-to-noise ratio and the maximum phase difference tolerance during antenna baseline design. Then, the direction finding result quality assessment of each baseline is obtained through the relationship between the difference and the threshold value.

[0010] S3. The quality assessment data of the direction finding results of each baseline are multiplied and fused to obtain the final quality assessment of the interferometer direction finding results.

[0011] Furthermore, in step S1, the formula for calculating the reverse phase difference is:

[0012]

[0013] Where, d n f is the baseline length of the nth antenna. c θ is the signal carrier frequency, θ is the direction finding result, and c is the speed of light.

[0014] Furthermore, step S1 also includes based on the theoretical phase difference Calculate the theoretical phase difference folded within 360° The calculation formula is as follows:

[0015]

[0016]

[0017] in, This indicates the floor function.

[0018] Further, in step S2, the phase difference is measured. Phase difference from theory The difference is:

[0019]

[0020] Here, || represents the absolute value operation.

[0021] Furthermore, step S2 also includes based on the difference Calculate the difference within 360° of the fold. The calculation formula is as follows:

[0022]

[0023] Furthermore, the maximum phase difference deviation caused by noise is calculated based on the signal-to-noise ratio (SNR):

[0024]

[0025] Furthermore, based on the difference Maximum phase difference deviation Φ caused by noisetheory Calculate the direction finding quality for each baseline:

[0026]

[0027] Where, max{Φ theory ,Φ thres} represents the maximum phase deviation Φ caused by noise. theory Maximum phase difference tolerance Φ during antenna baseline design thres Choose the larger of the two.

[0028] Furthermore, in step S3, the direction-finding results of each baseline are multiplied to obtain a comprehensive evaluation result of the interferometer direction-finding results quality:

[0029] Cfid total =Cfid1·Cfid2…Cfid N .

[0030] A computer device includes a memory and a processor, the memory storing a computer program, characterized in that the processor executes the computer program to implement the steps of the above-described interferometer direction finding result quality assessment method.

[0031] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the above-described method for evaluating the quality of interferometer direction finding results.

[0032] The beneficial effects of this invention are as follows:

[0033] This invention utilizes the azimuth and baseline length of the direction finding to perform a reverse calculation of the theoretical phase difference. Then, based on the difference between the actual measured phase difference and the theoretical phase difference for each baseline, a threshold value is calculated using the signal-to-noise ratio and the maximum phase difference tolerance during antenna baseline design. The relationship between this difference and the threshold value is then used to obtain a quality assessment of the direction finding results for each baseline. Finally, the quality assessment data for each baseline are multiplied and fused to obtain the final interferometer direction finding result quality assessment. This quality assessment data can be used to evaluate the reliability of the interferometer's direction finding results, thereby preventing performance degradation due to direction finding errors. Attached Figure Description

[0034] Figure 1 This is a flowchart of the interferometer direction finding result quality assessment method according to an embodiment of the present invention. Detailed Implementation

[0035] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments are now described. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention; that is, the described embodiments are only a part of the embodiments of the invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0036] Example 1

[0037] like Figure 1 As shown, this embodiment provides a method for evaluating the quality of interferometer direction finding results, including the following steps:

[0038] S1. Calculate the theoretical phase difference in reverse using the azimuth and baseline length of the direction finding;

[0039] S2. Based on the difference between the actual measured phase difference and the theoretical phase difference of each baseline, the threshold value is calculated through the signal-to-noise ratio and the maximum phase difference tolerance during antenna baseline design. Then, the direction finding result quality assessment of each baseline is obtained through the relationship between the difference and the threshold value.

[0040] S3. The quality assessment data of the direction finding results of each baseline are multiplied and fused to obtain the final quality assessment of the interferometer direction finding results.

[0041] Preferably, in step S1, the formula for calculating the reverse phase difference is:

[0042]

[0043] Where, d n f is the baseline length of the nth antenna. c θ is the signal carrier frequency, θ is the direction finding result, and c is the speed of light.

[0044] Because in the design of interferometer baselines, in order to meet the requirements of high-precision direction finding, the theoretical phase difference is usually... It may exceed 360°, while all measured phase differences are within 360°. Preferably, based on theoretical phase differences. Calculate the theoretical phase difference folded within 360° The calculation formula is as follows:

[0045]

[0046]

[0047] in, This indicates the floor function.

[0048] Preferably, in step S2, the phase difference is measured. Phase difference from theory The difference is:

[0049]

[0050] Here, || represents the absolute value operation.

[0051] Considering the difference in phase There may also be blurring within 360 degrees, therefore further calculation of the difference between the unblurred values ​​is needed. The calculation formula is as follows:

[0052]

[0053] And based on the signal-to-noise ratio (SNR), the maximum phase difference deviation caused by noise is calculated:

[0054]

[0055] Based on the difference Maximum phase difference deviation Φ caused by noise theory Calculate the direction finding quality for each baseline:

[0056]

[0057] Where, max{Φ theory ,Φ thres} represents the maximum phase deviation Φ caused by noise. theory Maximum phase difference tolerance Φ during antenna baseline design thres Choose the larger of the two.

[0058] Finally, the quality of the direction finding results from each baseline is multiplied to obtain a comprehensive evaluation result of the interferometer direction finding quality:

[0059] Cfid total =Cfid1·Cfid2…Cfid N .

[0060] Specifically, assuming the carrier frequency f of the signal c =1GHz, antenna baseline lengths are d1=0.15m, d2=0.4m, d3=1.2m, the signal-to-noise ratio (SNR) of the received signal is SNR=15dB, and the measured phase difference of the received signal is... The direction finding result is θ = 45°, and the maximum tolerable phase deviation in the baseline design of the interferometer system is Φ. thres =30°. Accordingly, the specific steps for evaluating the quality of interferometer direction finding results are as follows:

[0061] 1. Based on the carrier frequency f of the signal cThe direction finding result θ and the antenna baseline lengths d1, d2, ..., d N Calculate the theoretical phase difference of the current direction finding result:

[0062]

[0063] get:

[0064]

[0065] in, The unit is radians, and c is the speed of light.

[0066] 2. Based on theoretical phase difference Calculate the theoretical phase difference folded within 360° get:

[0067]

[0068] 3. Estimate the theoretical phase difference With measurement phase difference The difference get:

[0069]

[0070] 4. Considering the phase difference There may also be blurring within 360 degrees, therefore further calculation of the difference between the unblurred values ​​is needed. get:

[0071]

[0072] 5. Based on the signal-to-noise ratio (SNR), calculate the maximum phase difference deviation Φ caused by noise. theory ,get:

[0073] Φ theory =30.5°

[0074] 6. Based on and Φ theory Calculate the direction finding quality for each baseline:

[0075]

[0076] get:

[0077] Cfid1=0.894, Cfid2=0.944, Cfid2=1

[0078] 7. Multiply the direction finding results of each baseline to obtain a comprehensive evaluation result of the interferometer direction finding results quality, resulting in:

[0079] Cfidtotal =0.843

[0080] The above processing can be used to assess the reliability of the interferometer's direction finding results, thereby preventing performance degradation due to direction finding errors.

[0081] Example 2

[0082] This embodiment is based on embodiment 1:

[0083] This embodiment provides a computer device, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the interferometer direction finding result quality assessment method of Embodiment 1. The computer program can be in the form of source code, object code, executable file, or some intermediate form.

[0084] Example 3

[0085] This embodiment is based on embodiment 1:

[0086] This embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the interferometer direction finding result quality assessment method of Embodiment 1. The computer program can be in the form of source code, object code, executable file, or some intermediate form. The storage medium includes any entity or device capable of carrying computer program code, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc. It should be noted that the content contained in the storage medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the storage medium does not include electrical carrier signals and telecommunication signals.

[0087] It should be noted that, for the sake of simplicity, the foregoing method embodiments are described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

Claims

1. A method of evaluating the quality of interferometric direction finding results, characterized in that, The method comprises the following steps: S1. Reverse calculation of the theoretical phase difference using the bearing of the direction finding and the baseline length; S2. Based on the difference between the actual measured phase difference of each baseline and the theoretical phase difference, the threshold value is calculated through the signal-to-noise ratio and the maximum phase difference tolerance when the antenna baseline is designed, and then the quality evaluation of the direction finding result of each baseline is obtained through the relationship between the difference and the threshold value; S3. The quality evaluation data of the direction finding result of each baseline are multiplied to obtain the final interferometer direction finding result quality evaluation; In step S1, the reverse calculation formula of the theoretical phase difference is: wherein is the baseline length of the n th antenna, is the signal carrier frequency, is the direction finding result, and c is the speed of light.

2. The interferometer direction-finding result quality evaluation method according to claim 1, characterized in that, Step S1 further comprises calculating the theoretical phase difference based on the theoretical phase difference calculating the theoretical phase difference folded within 360° with the formula: wherein denotes a floor operation.

3. The interferometer direction-finding result quality assessment method according to claim 2, c h a r a c t e r i z e d b y In step S2, the phase difference is measured the difference between the measured phase difference and the theoretical phase difference is the difference between the measured phase difference and the theoretical phase difference is wherein denotes an absolute value operation.

4. The interferometer direction-finding result quality evaluation method according to claim 3, characterized in that, Step S2 also comprises calculating the difference value based on the difference between the two values calculating the difference value folded within 360° with the formula: 。 5. The interferometer direction-finding result quality assessment method according to claim 4, characterized in that, In step S2, the signal-to-noise ratio is calculated based on the signal strength and the noise strength The maximum phase difference deviation due to noise is calculated by the following formula: 。 6. The interferometer direction-finding result quality assessment method according to claim 5, c h a r a c t e r i z e d by In step S2, the difference and the maximum phase difference deviation caused by noise The quality of the direction finding result of each baseline is calculated, and the calculation formula is: wherein, represents the maximum phase deviation caused by noise the maximum phase difference tolerance at the time of antenna baseline design the larger of the two.

7. The interferometer direction-finding result quality assessment method according to claim 6, c h a r a c t e r i z e d by, In step S3, the quality of the direction finding result of each baseline is multiplied to obtain the comprehensive evaluation result of the interferometer direction finding result quality: 。 8.A computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the computer device is configured to perform the method according to any one of claims 1-7. The processor executes the computer program to realize the steps of the interferometer direction finding result quality evaluation method in any one of claims 1-7.

9. A computer readable storage medium storing a computer program, characterized in that, The computer program is executed by the processor to realize the steps of the interferometer direction finding result quality evaluation method in any one of claims 1-7.

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