A Method of Realizing Direct Wave Interference Suppression Using Coded Phase Modulation Signal

Abstract

The invention discloses a method of inhibiting direct wave interference by employing code phase modulation signals. The method comprises the steps of determining central frequency, bandwidth and pulse width of code phase modulation signals; adjusting coding forms and phase information of the code phase modulation signals, generating all candidate emission signals, calculating autocorrelation coefficients, screening the candidate emission signals and obtaining a preliminary emission signal set; calculating cross correlation characteristics of all signals in the set for the preliminary emission signal set, further screening the emission signals and obtaining a new emission signal set; and calculating fuzziness functions of signals in the emission signal set, obtaining doppler tolerance through the fuzziness functions, converting the doppler tolerance into theory velocity measurement precision, comparing the theory velocity measurement precision of each signal in the emission signal set with an allowed velocity variation scope of an active sonar task target and then selecting suitable emission signals in the emission signal set based on a comparison result.

Description

technical field [0001] The invention relates to the field of active sonar digital signal processing, in particular to a method for suppressing direct wave interference by using coded phase modulation signals. Background technique [0002] When ships are sailing in formation at sea, the active sonar on the ship will not only receive the echo signal from the target, but also receive the same-frequency direct wave interference signal from the friendly ship from time to time. Due to the limitations of hardware facilities and environmental conditions, the available frequency bandwidth of each ship's signal transmission is quite limited, resulting in a greatly reduced detection performance of the ship. How to effectively reduce the impact of friendly ship co-channel interference signals on the detection results is an urgent problem in the design of active sonar. Due to the small distance between the ship formations and the one-way attenuation of the co-channel interference direct...

AI Technical Summary

Problems solved by technology

So in this case, if the dynamic range of the AD sampler is too small, the direct wave will completely limit the signal at the receiving end, and the weak echo signal of the target will not be detected.

Under such high energy difference conditions, conventional signal processing methods are difficult to detect target echo signals

[0006] To sum up, the existing direct wave interference suppression methods have their own defects and cannot fully meet the needs of users

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