Sea surface micro-motion target Radon-linear contact transformation long-time phase-coherent accumulation detecting method
A micro-moving target and coherent accumulation technology, applied in radio wave measurement systems, instruments, etc., can solve the problems of compensation performance limitation, reduction of coherent accumulation gain, dispersion, etc., to improve SCR, increase coherent accumulation gain, increase Effect of Estimation Accuracy
Active Publication Date: 2014-11-19
NAVAL AVIATION UNIV
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Problems solved by technology
At present, the long-term coherent accumulation of micro-moving targets on the sea surface mainly faces the following two problems: On the one hand, due to the continuous improvement of the radar range resolution and the rapid movement of the target, the target echo envelope in the long-term accumulation Walking between different pulse periods is called the Across Range Walk (ARU), which causes the energy of the target to disperse in the range direction, and it is necessary to perform echo range migration compensation before detection; When the parameters are accumulated, the micro-motion of the target (non-uniform acceleration motion or three-axis rotation) will cause the echo phase to change, so that the radar echo signal has time-varying characteristics and appears as a high-order phase form, and the Doppler frequency of the target will cross Multiple Doppler units, called Doppler Frequency Migration (DFM), broaden the spectrum of the target and reduce the coherent accumulation gain
[0005] At present, there are few long-term coherent accumulation methods that can compensate for range and Doppler migration at the same time, and the accumulation gain is often affected by the signal-to-noise (noise) ratio, which is not suitable for signal processing in complex clutter background environments
For the range migration effect of micro-moving targets on the sea surface, the existing compensation methods include envelope correlation methods (such as cross-correlation method, minimum entropy method, spectral peak tracking method, etc.), but in the case of low SCR, due to the adjacent echo correlation The advantage of the Keystone transform method is that it can realize the distance walking correction of the target echo without knowing the target's moving speed, but it depends on the Doppler ambiguity of the target echo; Radon - The Fourier Transform method (Radon-Fourier Transform, RFT) solves the problem of coupling distance migration and phase modulation by jointly searching the target parameters in the parameter space, but it assumes that the target moves at a uniform speed and cannot process micro-motion signals
For Doppler migration compensation, existing methods include De-chirp method, Chirp-Fourier transform method, polynomial phase method and fractional Fourier transform method (FRactional Fourier Transform, FRFT), etc., but the compensation performance is poor. Limited by estimated signal length
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[0028] In order to explain the range migration and Doppler migration effects of the sea surface micro-moving target involved in the present invention, a radar echo modulation model of the sea surface micro-moving target is first given. The geometric relationship of sea surface targets observed by shore-based radar figure 1 Shown, including target fixed reference coordinate system C ref = (X, Y, Z) and target motion coordinate system C mov = (X, y, z).
[0029] ●Micro-Doppler modulation model of translational target
[0030] In order to obtain high resolution and reduce effective bandwidth, it is assumed that the coherent system radar transmits linear frequency modulation (LFM) signals
[0031] s t ( t ) = rect ( t T p ) exp { j 2 π [ f c t + 1 2 kt 2 ] }
[0032] Where rect ( u ) = 1 , | u | ≤ 1 / 2 0 , | u | > 1 / 2 , f c Is the radar carrier...
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The invention relates to a sea surface micro-motion target Radon-linear contact transformation (RLCT) long-time phase-coherent accumulation detecting method which belongs to the technical field of radar signal processing and detection. The method comprises the following steps: (1) performing demodulation and pulse compression on radar echo, and completing calculation in pulse; (2) pre-judging sea conditions and detection target types and determining long-time phase-coherent accumulation parameters; (3) adopting RLCT compensation distance and Doppler migration and calculating micro-motion target signal energy; (4) viewing and searching parameters and establishing a distance-RLCT area detection unit graph, and carrying out constant false-alarm detection on the distance-RLCT area detection unit graph; and (5) evaluating micro-motion feature parameters, and outputting motion trace points. The sea surface micro-motion target Radon-linear contact transformation long-time phase-coherent accumulation detecting method applies sea surface target micro-motion features to target detection, meanwhile utilizes range and phase information of the echo to perform long-time phase-coherent accumulation to carry out long-time phase-coherent accumulation, effectively compensates distance and the Doppler migration, improves accumulation gain, has the capacity to detect a micro-motion target in strong clutter, can obtain the motion trace points of the target, and has popularization application value.
Description
1. Technical Field [0001] The present invention belongs to the technical field of radar signal processing and detection. More specifically, the present invention relates to a Radon-linear canonical transformation long-term coherent accumulation detection method for sea surface micro-moving targets, which can be used for the radar of micro-moving targets in the background of strong sea clutter. Detection and processing. 2. Background technology [0002] Reliable and robust weak target detection technology under high sea conditions is always a difficult problem in the field of radar signal processing. Traditional target detection methods based on statistical theory treat sea clutter as a random process, but both target models and clutter models show a diversified development trend, especially clutter distribution models, which are often not established or not fully established in complex environments. Therefore, the classic target detection method cannot obtain the expected detect...
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IPC IPC(8): G01S7/41
Inventor陈小龙关键王国庆蔡复青丛瑜刘宁波黄勇何友
OwnerNAVAL AVIATION UNIV