Sonar Signal Processing Directional Noise Suppression
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Solution Overview
Problem
Existing sonar devices face challenges in improving target signal detection ability due to difficulties in effectively suppressing noises, particularly atmospheric and active pulse oscillation sounds, which can lead to false alarms and reduced operator efficiency.
Innovation Solution
A sonar device and signal processing method that divide received signals into frequency cells, calculate direction vectors, and perform noise suppression based on the difference between signal and resultant vector directions, selectively suppressing stationary noises while minimizing impact on target signals with high directivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If noise suppression processing is performed on received signals to remove stationary noises, then noise reduction effect is improved, but target signals may be mistakenly suppressed causing false alarms
Solution Approach 1:
The patent applies different noise suppression strengths to different frequency cells based on their directional characteristics. Frequency cells with small direction differences (likely target signals) receive weaker suppression, while frequency cells with large direction differences (likely stationary noises) receive stronger suppression. This localized differentiation resolves the contradiction by protecting potential target signals while still suppressing noises effectively.
Solution Approach 2:
The patent dynamically adjusts the noise suppression parameter (suppression strength) based on the direction difference of each frequency cell. By changing the suppression parameter according to the directional characteristics, the system achieves both noise reduction and target signal protection, resolving the contradiction between noise suppression effectiveness and false alarm prevention.
2Measurement precision
If directional analysis is performed on each frequency cell to improve target signal discrimination, then target detection accuracy is improved, but calculation complexity increases
Solution Approach 1:
The patent divides the received signal into multiple frequency cells and performs directional analysis on each cell independently. This segmentation allows the system to focus computational resources on specific frequency ranges, improving target detection accuracy while managing calculation complexity through distributed processing.
Solution Approach 2:
The patent extracts the directional information from each frequency cell and uses only the essential parameter (direction difference) for noise suppression decisions. By taking out only the critical directional characteristic and ignoring other redundant information, the system achieves accurate target detection without excessive calculation complexity.
Data Source
AI summary
Provided are a sonar device, signal processing method, and recording medium which contribute to improvement in target signal detection ability of an operator. The sonar device comprises a signal detection processing unit and a noise suppression processing unit. The signal detection processing unit calculates a direction vector for each frequency cell and also calculates a resultant vector direction obtained by summing up the direction vectors of all the frequency cells. The noise suppression processing unit calculates, for each frequency cell, the difference between the resultant vector orientation and the signal direction of the frequency cell, and performs a first noise suppression process for suppressing stationary noises included in a received signal such that the noise suppression effect be smaller on a signal of a frequency cell whose signal direction has a smaller difference from the resultant vector direction, and be larger on a signal of a frequency cell whose signal direction has a larger difference from the resultant vector direction.