Phase-coherent accumulation method based on frequency domain shear

Abstract

The invention relates to a phase-coherent accumulation method based on frequency domain shear. When a target echo envelope walks over a range unit within a phase-coherent processing interval, the envelope walking track of a range-slowing-down time dimension signal space is regarded as an image and rotates and translates by a certain angle by a frequency domain shear processing method, each rotary transferring process is subjected to slowing-down time dimension fast Fourier transform to obtain phase-coherent accumulation peak values, so that each rotating angle corresponds to one accumulation peak value, the gradient and the start distance of a corresponding target track are obtained by the aid of the maximum peak value, and the movement track of a target is obtained. Range walking correction and target energy accumulation are effectively realized, and the phase-coherent accumulation method is applicable to radar dim target signal detection and range walking correction in radar imaging technology, high in precision, rapid in operation, easy in engineering realization and fine in robustness.

Description

technical field [0001] The invention belongs to the technical field of target detection and tracking in radar systems, in particular to a coherent accumulation method based on frequency domain shear. Background technique [0002] Stealth targets, UAVs, cruise missiles and other weak targets pose a serious threat to traditional radar systems, and long-term coherent accumulation technology can effectively detect stealth and other weak targets. However, in the long-term coherent accumulation processing of radar signals, the long-distance walking caused by target motion seriously affects the accumulation and detection of target energy. And with the demand for high resolution of radar, the distance unit is getting smaller and smaller, and the phenomenon of crossing the distance unit is more serious. For the problem of cross-distance unit compensation, accurate estimation of target motion parameters is required, but in general, when the signal-to-noise ratio (SNR) is low, accurat...

AI Technical Summary

Problems solved by technology

For the method of searching for target motion parameters, its time domain shift or addressing amount is an integer, and there is energy accumulation loss when it is not interpolated, and the amount of calculation is large

The Keystone transform can perform uniform compensation across distance units within a certain speed range (see "Zhang Shunsheng, Zeng Tao, Faint Target Detection Based on Keystone Transformation, Acta Electronica Sinica, 2005, 33(6): 1675-1678."), but The algorithm needs to estimate the Doppler ambiguity number, otherwise the performance will be severely degraded

In image processing, the Hough transform and Radon transform of line detection are applied to the "tracking before detection (TBD)" technology, but due to the SNR threshold phenomenon of non-coherent accumulation, the accumulation efficiency for low SNR is not high

Coherent Radon transform is used to detect faint targets, which uses rotation and bilinear interpolation to realize Radon transform and performs phase compensation through Doppler filter to realize coherent accumulation (see "Javier C M, Javier G M, et al., A Coherent Radon Transform for Small Target Detection, IEEE Rader Conference, 2009:1-4."), but there is a loss in interpolation and it is easy to cause side lobes

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