Outer radiation source weak signal detection method based on PCA (principal component analysis)

Abstract

The invention provides an outer radiation source weak signal detection method based on PCA (principal component analysis). The method comprises the following steps of solving an autocorrelation matrix R=E{x(t)x<H>(t)} of a sampling sequence x(t); carrying out SVD (singular value decomposition) on the autocorrelation matrix R, to obtain R=Q Lambda Q<H>, utilizing the decomposed diagonal matrix Lambda and unitary matrix Q to carry out linear conversion on the sampling sequence x(t) to obtain a strength-decreased sequence y(t) of received signals; carrying out the two-dimensional correlation of time frequency distribution on the third path to the Mth path of signals in the received signal y(t) to obtain the corresponding correlation value, namely the absolute value of psi i (tao, f); when the signal-to-noise ratio of one certain path is greater than or equal to a threshold value, determining the time delay and Doppler frequency corresponding to a peak point as the time delay and Doppler frequency displacement of one target; and when the signal-to-noise ratio of one path is smaller than the threshold value, judging that the signal of the path has no target. The method has the advantage that a weak target signal can be extracted under the conditions of strong same-frequency interference and low signal-to-noise ratio.

Description

technical field [0001] The invention belongs to signal processing technology, in particular to weak signal detection technology. Background technique [0002] The dual multistatic radar system based on external radiation sources can use civilian TV signals, broadcast signals, communication signals, satellite signals, and mobile phone base stations with known geographic locations as illumination sources to detect echo signals reflected by moving targets in the air. , to realize the detection and location tracking of the target. Because the external radiation source radar itself does not emit signals, the whole radar system has the advantages of strong concealment, strong anti-interference ability and strong survivability, so it has attracted extensive attention from various countries. [0003] The principle of the system is shown as figure 1 As shown, taking the broadcast signal as an example, the received signal from the radar includes the direct wave from the broadcast to...

AI Technical Summary

Problems solved by technology

However, this method will fail when the target signal is very weak. At the same time, because co-channel interference may also exist in the same beam, this will make it impossible to extract the target time delay and Doppler frequency parameters, so that the target cannot be estimated DOA

Images