One-station fixed frequency-modulated continuous wave double-base SAR imaging method

Abstract

The invention discloses a one-station fixed frequency-modulated continuous wave double-base SAR imaging method. The one-station fixed frequency-modulated continuous wave double-base SAR imaging method mainly solves the problems that azimuth range migration spatial-variant properties and orientation frequency-modulated spatial-variant properties can not be corrected at the same time according to an existing method. The method is achieved according to the steps that (1) a two-dimension time domain echo signal of a target is acquired, and a distance frequency domain azimuth time domain echo signal of the target is calculated; (2) azimuth range migration spatial-variant properties and orientation frequency-modulated spatial-variant properties are corrected according to the distance frequency domain azimuth time domain echo signal; (3) residue phase compensation is conducted on the corrected signal, and range-direction range migration spatial-variant properties are corrected; (4) azimuth pulse compression is conducted on the signal after range-direction range migration spatial-variant property correction, and azimuth inverse Fourier transform is carried out to acquire a target time domain image. The one-station fixed frequency-modulated continuous wave double-base SAR imaging method has the advantages of being capable of correcting azimuth range migration spatial-variant properties and orientation frequency-modulated spatial-variant properties at the same time, high in achieving efficiency and capable of being used for one-station fixed frequency-modulated continuous wave double-base SAR imaging.

Description

technical field [0001] The invention belongs to the technical field of radar, in particular to an imaging method of a one-station fixed FM continuous wave bistatic SAR in synthetic aperture radar imaging technology, which can be used for imaging of a one-station fixed bistatic SAR in an FM continuous wave mode. Background technique [0002] Frequency modulated continuous wave FMCW synthetic aperture radar SAR combines continuous wave and synthetic aperture imaging technology, and has the characteristics of simple structure, small size, light weight, low energy consumption, low cost, low interception rate, and strong anti-interference ability. The frequency modulation continuous wave bistatic SAR system combines the structural characteristics of bistatic radar with separate transceivers, which can avoid the interference problem between the transceiver antennas when FMCW signals are applied in monostatic SAR, taking into account the advantages of bistatic and FMCW radars, and h...

AI Technical Summary

Problems solved by technology

However, due to the relative position changes between the receiver and the transmitter of a fixed bistatic SAR, this change leads to different range cell migration RCM and azimuth modulation frequencies in the same range gate, that is, a fixed bistatic SAR Bistatic SAR is space-varying in azimuth, so traditional imaging algorithms based on invariant azimuth and space, such as RD algorithm, CS algorithm, and ωK algorithm, are not suitable for this type of bistatic SAR imaging problem.

[0005] A nonlinear The scaling method is used to compensate the space-variation of the azimuth modulation frequency, but this method corrects the echo signal in the two-dimensional time domain and ignores the change of the range migration along the azimuth direction. When the change is relatively large, a larger error will be introduced

[0006] Literature "Robert Wang, Otmar Loffeld, Yew Lam Neo, Holger Nies, Ingo Walterscheid, Thomas Espeter, Jens Klare, and Joachim H.G. Ender, Focusing Bistatic SAR Data in Airborne / Stationary Configuration, IEEE Trans. On Geoscience and Remote Sensing, Vol. 48, No.1,452-464,2010" proposed a method based on data partitioning, which divides the data into blocks, although the change of distance migration along the azimuth direction and the frequency of azimuth modulation along the azimuth direction are considered However, this method requires matching filtering in each data block, which requires a large amount of calculation, and is only suitable for situations where the azimuth range does not change much.

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