Delay inequality estimating method based on frequency variance weight

Abstract

The invention provides a delay inequality estimating method based on frequency variance weight and is used for estimating delay inequality of object radiation signals received by different reception array elements in a hydro-acoustic positioning system. The method comprises steps that time domain correlation spectrum and corresponding initial delay inequality of each frequency unit are calculated for multiple times; a frequency variance corresponding to each initial delay inequality is acquired through calculation, reciprocals of the frequency variances are calculated to form weight factors, the weight factors corresponding to each initial delay inequality are summed to acquire the final time domain correlation spectrum, and the final delay inequality is calculated from the final time domain correlation. According to the method, a guide signal is employed to carry out frequency domain cross correlation of each frequency unit, by utilizing characteristics of a non-true-value delay inequality corresponding to the frequency unit in a random mode and a true-value delay inequality corresponding to the frequency unit in a relatively consitent mode, frequency variance statistics of each delay inequality estimation result is carried out, the proportion of a line spectrum signal corresponding to the true-value delay inequality in delay inequality estimation is stressed, and the proportion of a noise unit corresponding to the non-true-value delay inequality in delay inequality estimation is weakened.

Description

technical field [0001] The invention relates to the field of sonar signal processing, in particular to a time delay difference estimation method based on frequency variance weighting. Background technique [0002] Because active sonar is easy to expose, passive sonar is often used to detect underwater targets. With the continuous improvement of vibration reduction and noise reduction technology, the target radiation noise is continuously reduced compared with the environmental noise, resulting in the continuous reduction of the prior knowledge that sonar equipment can provide for its received signals. The signal detection method based on broadband energy integration can no longer meet the detection requirements of underwater remote targets in passive sonar detection. [0003] Studies have shown that the rotation of the propeller of the underwater target will cut the water body to generate low-frequency signals, part of which will directly appear in the target radiation sign...

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Problems solved by technology

[0005] The purpose of the present invention is to overcome the problem of the time delay difference estimation of receiving target radiation signals between array elements in the underwater acoustic positioning system that cannot be well realized in the prior art when the target radiation signal frequency is unknown under low signal-to-noise ratio. The invention provides a time delay difference estimation method based on frequency variance weighting

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