Three-dimensional imaging kinematic error compensation method for re-sailing array synthetic aperture radar

Abstract

The invention discloses a three-dimensional imaging kinematic error compensation method for a re-sailing array synthetic aperture radar. The method comprises the following steps that: obtaining arrayeach submatrix position corresponding to each sailing and array deformation measurement data, and carrying out polynomial fitting; through MURA (Modified Uniformly Redundant Array) positive and negative coding, carrying out spatial modulation on echo data; adopting a three-dimensional BP (Back-Projection) imaging algorithm to obtain an SAR (Synthetic Aperture Radar) three-dimensional complex imagepair corresponding to each sailing; carrying out interference processing on the three-dimensional complex image corresponding to a MURA orthocode; establishing a relational expression between compleximage frequency domain coefficient vectors after SAR echo signal-interference, and solving each sailing relational expression; carrying out inverse transformation on the frequency domain coefficientvectors obtained by solving into a spatial domain, and equivalently realizing array deformation error compensation and single-sailing three-dimensional imaging; carrying out phase compensation on thesingle-sailing complex image formed by the MURA orthocode echo; and carrying out coherent addition on each compensated complex image to realize re-sailing array SAR three-dimensional imaging. The method has an important meaning for the application of onboard / satellite-borne re-sailing observation data.

Description

technical field [0001] The present disclosure relates to the field of radar imaging processing, and in particular to a motion error compensation method for three-dimensional imaging of heavy navigation array synthetic aperture radar. Background technique [0002] Array antenna SAR achieves three-dimensional resolution of the observation scene by forming a two-dimensional synthetic aperture array and broadband signals in the wave propagation direction in the sampling space, where the resolution in the array direction is limited by the length of the cross-track array. Over-sampling in the array direction can expand the equivalent array length to improve the cross-track resolution (see Li Daojing, Teng Xiumin. Cross-Track Sparse Flight Simulation Analysis for Airborne Sparse Array Downward-Looking 3D Imaging Radar[C]. in Geoscience and Remote Sensing Symposium (IGARSS), Canada, July 2011: 1686-1688). Under the ideal re-travel oversampling conditions, the spatial positions corr...

AI Technical Summary

Problems solved by technology

In practice, the array SAR based on heavy navigation oversampling realizes three-dimensional imaging through multiple passes of the same scene at different times. The relative positions between the phase centers in the interior will also change, seriously affecting image inversion (see Salzman J., Akamine D., Lefevre R., et a1.Interrupted synthetic aperture radar(SAR)[J].IEEE Aerospace and Electronic Systems Magazine, 2002, 17(5): 33-39)

[0003] In view of the above background, relevant researchers have worked on array error correction, platform motion error compensation, and multi-pass echo data registration (see Yang Zemin, Sun Guangcai, Xing Mengdao, etc. Airborne 3D SAR motion compensation based on multi-channel joint self-focusing technology[ J]. Journal of Electronics and Information Technology, 2012, 34(7): 1581-1588) and other aspects have done corresponding research work, but the research on the down-looking 3D imaging and motion error compensation of heavy-flying array SAR under the condition of motion error is relatively limited. few

Due to the heavy flight of the airborne array antenna SAR, on the one hand, there is an array deformation error, and on the other hand, there is a track curve offset, which brings many difficulties to its three-dimensional imaging.

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