Combined cooperative multi-satellite weak echo signal time delay and doppler frequency shift estimation method

Abstract

The invention discloses a combined cooperative multi-satellite weak echo signal time delay and doppler frequency shift estimation method. According to the method, multiple nonstop wave signals in a reference channel are separated; adaptive inhibition for nonstop wave signals and multi-path signals in an echo channel is carried out; fourth-order cyclic cumulant mutual fuzzy function processing based on four weighted fractional Fourier transform for the signals in the echo channel and the different nonstop wave signals is respectively carried out to acquire multiple characteristic vectors; after spectral peak extraction for fuzzy function peak values is carried out, corresponding coordinates are time delay and doppler frequency shift estimates; the multiple sets of time delay and doppler frequency shift estimates are converted into distances from targets to receivers and speeds, data fusion is further carried out, the distances and the speed values are converted into multiple sets of time delay and doppler frequency shift estimates after data fusion, and thereby time delay and doppler frequency shift of cooperative multi-satellite weak echo signals can be estimated; when a signal to noise ratio is greater than 10dB, a normalization mean square error of signal to noise ratio estimation is smaller than 1.

Description

technical field [0001] The invention belongs to the technical field of communication technology and signal processing, and in particular relates to a method for jointly estimating time delay and Doppler frequency shift of weak echo signals under multi-satellite coordination. Background technique [0002] With the complexity of the electromagnetic environment, traditional target detection technology cannot meet the requirements of detection accuracy and response capability. Therefore, how to use the interaction between the target and the radio wave propagation environment, clutter environment, etc. to detect the target by detecting the disturbance of the target to the radio wave environment is of great significance. After target detection, in order to obtain information such as target speed and locate the target, it is necessary to estimate the parameters of the weak echo signal. Time delay and Doppler frequency shift are important characteristic parameters to characterize t...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a joint estimation method of weak echo signal time delay and Doppler frequency shift under multi-satellite coordination, aiming at solving the problem of target detection and weak echo signal parameter estimation based on multiple satellite radiation sources The method has the problem of poor estimation performance of time delay and Doppler frequency shift of weak echo signals from multiple satellites in a low signal-to-noise ratio environment

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