A Direction Finding Method Based on Digital Beamforming for Multi-same-frequency Source Phase Interferometer

Abstract

The invention belongs to the technical field of electronic countermeasures, and in particular relates to a direction finding method of a multi-same-frequency signal source phase interferometer based on digital beamforming. In the present invention, in the multi-source direction finding process, after the array receives the radiation signal from the source, it performs digital beamforming, so that the radiation signal is incident from the width of the main lobe of the beam corresponding to the incoming wave direction, while the signals in other incoming wave directions only It can be incident on the side lobe of the beam, and at this time, the incoming wave direction of the signal source can be accurately measured by the phase interferometer method on the incident beam. The present invention implements spatial filtering by performing digital beamforming on the signals received by the antenna array, separates the same-frequency signal sources with different incoming wave directions, and realizes the measurement of the incoming wave directions of multiple same-frequency signal sources through phase interferometer direction finding , which solves the problem of phase interferometer direction finding under the condition of multiple sources.

Description

technical field [0001] The invention belongs to the technical field of electronic countermeasures, and in particular relates to a direction finding method of a multi-same-frequency signal source phase interferometer based on digital beamforming. Background technique [0002] Direction finding technology plays an important role in many fields, especially in the field of electronic countermeasures. It has been an active research topic to realize timely and accurate determination of the direction of the target signal source in a complex interference environment. The common phase interferometer direction finding method uses the phase difference formed by the incident radiation signal of the source on multiple receiving array elements at different positions to determine the direction of the source. This method has the advantages of short data processing time and mature technology, and is widely used. It is widely used in the direction finding and positioning of radiation sources....

AI Technical Summary

Problems solved by technology

Under certain conditions, this method can realize the direction finding of the incoming wave direction of multiple sources, but because this method only filters the radiation signal in the interference direction, the noise in the desired direction can still enter within the main lobe width of the beam, and Since the influence of noise on the signal strength is greater than that on the signal phase, the direction finding accuracy of the ratio amplitude method is inferior to that of the phase interferometer under the condition of large signal-to-noise ratio.

[0005] Phase interferometer direction finding needs to perform cross-correlation in the frequency domain or time domain on the signals received by the array elements at different positions to calculate the phase difference to estimate the incoming wave direction. However, in a complex electronic countermeasure environment, there are multiple same-frequency signals in different directions. When the source radiates an incoherent signal with the target signal, the phase difference between the received signals of each array element is no longer determined by the direction of arrival of the target signal and noise factors, but by the direction of arrival of multiple radiation signals including interference signals. Therefore, the direction finding method of the phase interferometer cannot distinguish multiple radiation sources in different directions in the airspace, and can only measure the direction of arrival of a single radiation source, which has poor anti-interference ability

[0006] At present, most of the research on phase interferometer direction finding revolves around the baseline design and improving the phase defuzzification algorithm to improve the speed or accuracy of direction finding. There is no public report on the research of phase interferometer direction finding under the condition of multiple sources. , so this is a worthwhile research direction

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