Doppler spectrum center frequency estimation method based on frequency shift iteration

Abstract

The invention provides a Doppler spectrum center frequency estimation method based on a frequency shift iteration. In the method, a spectral moment method estimation frequency shift is taken as an initial value; an integral interval is changed step by step so as to carry out iterated integral; the spectral moment method estimation frequency shift is used in each iteration till that a final frequency shift result convergence is performed; the result is taken as an optimum estimation value of a Doppler spectrum center frequency. Compared to a traditional spectral moment method, by using the method of the invention, an effect of estimating a center frequency by using the frequency shift iteration method is good, a mean absolute error and a root-mean-square error are small and estimation precision of the method is not restrained by a frequency shift resolution. The method is used in a Doppler wave observation radar so that ocean wave parameters of an accurate effective wave height, an average wave period and the like can be obtained.

Description

technical field [0001] The invention belongs to the field of radar signal processing, and relates to a method for estimating the center frequency of Doppler spectrum based on frequency shift iteration. The invention is applicable to shore-based microwave Doppler radar systems and high-frequency ground wave radars of various coherent mechanisms. Background technique [0002] Ocean observation is the basic means for human beings to understand the natural attributes and environmental characteristics of the ocean, and it is the cornerstone of the development of the ocean industry. In recent years, the United States, Britain, France, Germany, Russia, Norway, New Zealand and other countries are actively carrying out research on shore-based radar ocean remote sensing technology, so as to obtain undirected wave height spectrum, wave statistics (such as effective wave height, wave period, Ocean dynamics elements such as wave direction) and ocean surface currents. [0003] With the ...

AI Technical Summary

Problems solved by technology

This method uses the correlation function to estimate the center frequency of the spectrum. The disadvantage is that the estimation deviation of the center frequency will increase with the increase of the spectrum skew, and the sampling period should be as short as possible.

[0006] However, the actual received radar echo is inevitably "polluted" by noise, and the small signal-to-noise ratio reduces the estimation accuracy of the center frequency

In order to overcome this problem, scholars at home and abroad have done a lot of research work. At present, some progress has been made in the estimation of the center frequency of the Doppler spectrum, but the estimation effect is still not the best, mainly limited by how to determine Noise level, and separate the signal and noise, and then extract the spectral parameters

Images