Laser synthetic aperture radar image-forming range direction phase compensation process

Abstract

The invention discloses a method of compensating the laser aperture composed radar imaging distance to phase. The method comprises: respectively performing the difference frequency to the target path of the laser aperture composed radar and the target local oscillator path, the reference channel and the reference local oscillator path to obtain echo after difference frequency; calculating the first phase error ratio p(taux) of the target echo based on the second phase of the echo after difference frequency; precompensation the phase error using the p(taux) and constructing the auxiliary function S(p(taux)); obtaining the corresponding phase error ratio p'(taux) by the auxiliary function and compensating and compressing the distance of the target echo signal to the phase error. The invention solves the problem of echo phase error due to instability of the laser waveform, therefore the compensated echo is compressed in the azimuth direction.

Description

technical field [0001] The invention belongs to the technical field of radar and relates to imaging technology, in particular to a phase compensation method for laser aperture synthetic radar imaging range direction. Background technique [0002] The formation of a synthetic aperture lidar image requires the measurement of the phase change process of the returned lidar signal during the formation time of the synthetic aperture. This process is completed by coherent detection, that is, the laser echo signal is mixed with a stable local oscillator signal to realize the demodulation of the echo signal. Due to the large bandwidth of the chirp signal, the sampling rate must be at least 4THz to satisfy the Nyquist sampling interval. Current analog-to-digital converters cannot handle such a large bandwidth, so the echo signal is demodulated by mixing it with a copy of the transmitted signal. However, the waveform of the LFM laser is not ideally linear, and the waveform between pu...

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Problems solved by technology

[0004] The purpose of the present invention is to apply W. Buell's thought, propose a kind of laser synthetic aperture radar imaging distance direction phase compensation method, to solve the echo phase error problem caused by the instability of the laser waveform, so that the echo after compensation Well compressed in distance up

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