Waveform diversity method for array SAR three-dimension imaging

Abstract

The invention provides a waveform diversity method for array SAR three-dimension imaging. Simultaneous waveform transmission of transmitting antennas of a multi-transmit and multi-receive array SAR is realized through an OFDM-Chirp orthogonal waveform coding / decoding method, and channel responses corresponding to different transmitting antennas are distinguished from echo received by receiving antennas and are used as data input of three-dimension imaging. According to the waveform diversity method of the invention, the transmitting antennas simultaneously transmit same-band orthogonal waveforms. The problem that pulse repetition frequency pressure is too large in a traditional time diversity method and the problem that system bandwidth demand is too high and de-coherent in a frequency diversity method are solved. Meanwhile, as transmitting signals have normal-mode characteristics of linear frequency modulation signals and have ideal self-correlation characteristics, the waveform diversity method of the invention is more in line with application requirements of array SAR three-dimension imaging compared with a conventional waveform diversity method.

Description

technical field [0001] The invention relates to the technical field of radar, in particular to a waveform diversity method for array SAR three-dimensional imaging. Background technique [0002] The use of multi-transmit and multi-receive antenna arrays is a way to realize SAR three-dimensional imaging. 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 multi-transmission and multi-reception antenna array distributed along the direction of the wing forms a real aperture for resolution in this direction, thereby realizing three-dimensional resolution imaging of the observation area. [0003] However, in order to suppress signal ambiguity, multi-transmit multi-receive antenna arra...

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Problems solved by technology

At present, some studies have been carried out on the design of waveform diversity methods 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.), but these methods have limitations when used in imaging applications. On the one hand, the signal waveform of the normal-mode envelope cannot be used to make full use of the system transmitter power amplifier; on the other hand, the complex filter design cannot Integrate with existing imaging processors; on the other hand, it is not suitable for imaging distributed target scenes due to non-ideal autocorrelation properties

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