Atmospheric Noise Suppression Method for Extreme/Ultra Low Frequency Channels Based on Variance Median Filtering

Abstract

The invention relates to the technical field of radio long wave communication technology, and specifically relates to an extremely-ultra low frequency channel atmosphere noise suppression method based on variance median filtering. The extremely-ultra low frequency channel atmosphere noise suppression method based on variance median filtering includes the steps: constructing a multi-reference magnetic vector sensing system, synchronously receiving extremely-ultra low frequency signals through multi channels, and obtaining a magnetic induction output sampling point matrix X; according to the channel sampling point sequence, grouping X, estimating the variance of each group, and obtaining the variance matrix D; based on a large number decision criterion, performing pulse detection and two-stage adaptive median filtering on D; according to output of the second stage median filtering and input of the first stage median filtering, performing sequence reconstruction, and obtaining an output matrix Y; and performing power frequency harmonic interference and remaining atmosphere noise suppression on Y. As the extremely-ultra low frequency channel atmosphere noise suppression method based on variance median filtering taking the variance of the sampling point group as input of the adaptive median filter, the impulsiveness is improved. As the extremely-ultra low frequency channel atmosphere noise suppression method based on variance median filtering determines the pulse state of each element of the variance matrix based on the large number decision criterion, the pulse detection accuracy is improved and the defect that the performance is low when the median filtering is in the local high density pulse noise condition in the traditional method.

Description

Technical field [0001] The invention relates to the technical field of radio long-wave communication, in particular to an extreme / ultra-low frequency channel atmospheric noise suppression method based on variance median filtering. Background technique [0002] The signal attenuation rate of extremely / ultra-low frequency communication (3Hz~300Hz) is small, and it can penetrate the ground and seawater to reach a certain depth. Therefore, it has obtained certain application prospects in the fields of mine emergency communication and positioning, and underwater unmanned vehicle navigation. . The main factor affecting the performance of extremely / ultra-low frequency communication is the signal-to-noise ratio at the receiving end. Generally, the electromagnetic interference of extremely / ultra-low frequency communication mainly comes from channel atmospheric noise and local human interference. The atmospheric noise of the channel is caused by lightning activity in nature. There are f...

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Problems solved by technology

[0005] For the deficiencies in the above-mentioned existing methods in extremely / ultra-low frequency channel atmospheric noise suppression, the purpose of the present invention is to propose a method for suppressing atmospheric noise in extremely / ultra-low frequency channels based on variance median filtering, to effectively suppress atmospheric noise and improve Extremely / ultra-low frequency communication receiving signal-to-noise ratio

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