Radar slightly-moving target detection method based on Radon-linear canonical ambiguity function

Abstract

The invention relates to a radar slightly-moving target detection method based on a Radon-linear canonical ambiguity function (RLCAF) and belongs to the technical field of radar signal processing and detection. The radar slightly-moving target detection method based on the RLCAF comprises the following steps that (1) demodulation and pulse pressure are conducted on a radar echo in the distance direction so that in-pulse accumulation can be completed; (2) the type of a target to be detected is predicted, and parameters are initialized; (3) the distance and Doppler migration are compensated through the RLCAF and signal energy of a slightly-moving target is accumulated; (4) the parameters are traversed and searched, an RLCAF domain detection unit figure is established, and constant false-alarm detection is conducted; (5) target moving parameters are estimated and moving trace points are output. According to the radar slightly-moving target detection method based on the RLCAF, the advantages of an ambiguity function and the advantages of linear canonical transformation are combined, non-uniform velocity translational motion target signals or turning target signals can be flexibly matched and accumulated in a clutter background, the signal-to-clutter ratio is improved, range migration can be compensated through the extraction of a target observation value in a distance-slow-time plane, phase-coherent accumulation for a long time is completed, the detection capacity of radar to the slightly-moving target is improved, and therefore the radar slightly-moving target detection method based on the RLCAF is wide in applicability.

Description

1. Technical field [0001] The invention belongs to the technical field of radar signal processing and detection. More specifically, the invention relates to a radar weak moving target detection method based on Radon-linear canonical ambiguity function, which can be used for radar detection processing of weak moving targets in complex environments. 2. Background technology [0002] In recent years, the emergence of low-altitude / ultra-low-altitude penetration, anti-radiation missiles (Anti Radar Missile, ARM), comprehensive electronic countermeasures (Electronic Counter Measures, ECM) and stealth targets have greatly weakened the ability of radar to detect targets, and have The living environment of radar presents serious challenges. In particular, stealth targets (such as stealth aircraft, stealth ships, etc.) and high-speed maneuvering targets pose more and more serious threats to modern radars, and have been highly valued by countries all over the world. On the one hand, t...

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Problems solved by technology

However, in practical engineering applications, the above assumptions are no longer valid

On the one hand, due to the continuous improvement of radar range resolution and the increase of accumulation time, the target echo envelope moves between different pulse periods, and the range migration effect (Across Range Walk, ARU) appears, making the available coherent accumulation pulse number decreases, the accumulated target energy is scattered in the distance direction; on the other hand, in the long accumulation time, the Doppler frequency of the high-speed maneuvering target changes nonlinearly with time, and it is difficult to use the linear frequency modulation (Linear Frequency Modulated, LFM) signal to model the echo Doppler, the target detection problem at this time becomes more complicated, for example, the jerk (jerk) caused by the thrust change of rockets and missiles during flight produces more than two orders of magnitude Phase, another example is the target detection under high sea conditions, the target is bumped with the sea surface ups and downs, and the echo phase is periodic. At this time, the target energy will spread in the Doppler dimension, and the frequency will span multiple Doppler units, which is called Doppler Frequency Migration (DFM), which reduces the coherent accumulation gain

[0004] In order to solve the problem of distance migration, the classic methods mainly include data segmentation method and envelope shift compensation method (time domain and frequency domain), but in the low signal-to-clutter (noise) ratio (Signal-to-Clutter / Noise Ratio, In the case of SCR / SNR), a better compensation effect cannot be obtained; the Keystone transform method depends on the Doppler ambiguity of the target echo; as a generalized Doppler filter bank processing method, the standard Radon-Fourier transform method (Radon-Fourier Transform, RFT) solves the problem of range migration and phase modulation coupling by jointly searching the target parameters in the parameter space, but when the target moves at a non-uniform speed, the RFT algorithm still has room for improvement

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