A Doppler Factor Estimation Method for Mobile Frequency Hopping Underwater Acoustic Communication

Abstract

The invention belongs to the technical field of underwater acoustic communication, and discloses a method for estimating the Doppler factor of mobile frequency-hopping underwater acoustic communication. The communication signal is synchronized at the receiving end, and chips are intercepted; and the Doppler frequency offset factor is performed on the intercepted chips. Measure and obtain the estimation result of Doppler frequency offset factor; pre-select the wavelet basis function as the wavelet basis function for denoising; decompose the estimation result of Doppler frequency offset factor to obtain the approximate coefficient and detail coefficient; calculate the threshold threshold; perform soft thresholding on the detail coefficient noise; reconstruct the Doppler frequency offset factor; group the Doppler frequency offset factor optimization results into groups, and take the median value of each group to represent the group; predict the median value of the next group of Doppler frequency offset factors; The next group of chips is selected, and the steps are repeated to predict the median value of the next group of Doppler frequency offset factors. The present invention selects the optimal denoising wavelet basis function, eliminates estimation errors caused by inaccurate synchronization and inaccurate slice selection, and obtains more accurate Doppler frequency offset factor estimation results.

Description

technical field [0001] The invention belongs to the technical field of underwater acoustic communication, and in particular relates to a method for estimating a Doppler factor in mobile frequency hopping underwater acoustic communication. Background technique [0002] With the implementation of the national marine strategy, underwater acoustic communication technology has received high attention and development, and has been widely used in various military and civilian fields, such as data and control command communication of unmanned underwater vehicles. As an important carrier of ocean detection and underwater acoustic communication, underwater vehicles have become a research hotspot in the field of ocean engineering in various countries. Underwater vehicles have the characteristics of concealment, maneuverability, and economy. [0003] Different from radio communication on land, the propagation speed of underwater sound is only about 1500m / s, and the propagation speed of...

AI Technical Summary

Problems solved by technology

[0005] The above several Doppler estimation methods have considered the Doppler frequency offset factor estimation within a single symbol or frame signal in a short period of time, but have not considered the Doppler frequency offset of multiple symbols or continuous frame signals The change process between factors reduces the accuracy and cannot meet the requirements of modern underwater acoustic communication

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