Array three-dimensional SAR data acquisition method

Abstract

The invention provides an array three-dimensional SAR data acquisition method. According to the array three-dimensional SAR data acquisition method, at every course-made-good slow moment when a radar platform moves along a track, echoes after sampling are decoded to achieve cross-course aperture synthesis imaging sampling by adopting a cross-course multi-transmitting multi-receiving thinned array and simultaneously transmitting / receiving OFDM-Chirp orthogonal waveform coding signals, so that signals sampled in the elevation direction, the track direction and the cross-course direction are acquired, and then three-dimensional imaging is performed to acquire a three-dimensional focusing image of a scene. According to the method, the cross-course array aperture synthesis is performed by simultaneously transmitting the orthogonal waveform coding signals, and compared with a time-division transmitting / receiving method, the method has the advantages that the pulse repetition frequency of a system can be reduced, and the echo storage data size is small.

Description

technical field [0001] The invention relates to the technical field of information acquisition and processing, in particular to an array three-dimensional SAR data acquisition method based on OFDM-Chirp waveform coding. Background technique [0002] In array SAR three-dimensional imaging, the radar uses the movement of the aircraft platform to form a synthetic aperture in the direction of the track for this direction resolution; the radar transmits a broadband signal along the elevation direction and then performs pulse compression for this direction resolution; in addition, the radar passes The antenna array distributed along the direction of the wing, that is, across the course, forms an equivalent real aperture to resolve the direction, thereby realizing three-dimensional resolution imaging of the observation area. [0003] In order to save system resources, multi-transmission and multi-reception antenna arrays that are sparsely distributed across the course are usually u...

AI Technical Summary

Problems solved by technology

The current array SAR 3D imaging data acquisition method mostly adopts the time-sharing method, but this method has poor timeliness and a large amount of data, which brings pressure to the design of system pulse repetition frequency parameters; some researches on waveform encoding / decoding methods have been carried out at home and abroad ([1 ] J.Li, P.Stoica, and X.Zheng, "Signal synthesis and receiver design for MIMO radar imaging," IEEE Transactions on Signal Processing, Vol.56, No.8, pp.3959-3968, 2008. [2 ] Deng, "Discrete frequency-coding waveform design for netted radar systems," IEEE Signal Processing Letters, Vol.11, No.2, pp.179-182, 2004.), although the shortcomings of the time-sharing method are overcome, these The method has limitations when used in imaging applications. On the one hand, the transmitted waveforms are not completely orthogonal, resulting in non-ideal autocorrelation characteristics, and inter-channel interference has a strong impact on subsequent imaging processing; on the one hand, the orthogonal encoding signal waveform uses nonlinear FM signal does not have normal-mode envelope characteristics, which is not conducive to signal power amplification

Therefore, in practice, it is necessary to construct an array 3D SAR data acquisition method based on waveform coding that can meet the requirements of orthogonality, maintain the characteristics of the normal-mode envelope waveform, and has the characteristics of strong timeliness, small data volume, and easy implementation. In addition, no related documents or patents related to it have been published in this respect

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