Protective phase airborne interference synthetic aperture radar (SAR) terrain altitude self-adaption motion compensation method

Abstract

The invention provides a protective phase airborne interference synthetic aperture radar (SAR) terrain altitude self-adaption motion compensation method. The method can essentially remove influences of fluctuation of an unknown terrain on motion compensation precision and comprises the following steps of (1) respectively utilizing a single antenna SAR motion compensation method to conducting motion compensation on interference SAR two channel data, and obtaining an interference multiple-image pair; (2) conducting reverse phase compensation on each multiple image, and enabling phase information of each pixel of each multiple image to restore to correspond to an antenna phase center track before motion compensation is carried out; (3) conducting multiple-image registering, interference phase extracting, flat-removing phase and phase unfolding, and obtaining an interference phase image without winding; (4) calculating slant distance value corresponding to all pixels of SAR multiple images of a first channel before the motion compensation is carried out; (5) calculating the interference base line position, the base line length and the base line inclined angle before the motion compensation is carried out according to antenna phase center track data of two channels; and (6) using the interference phase, the slant distance value, the interference base line position, the base line length and the base line inclined angle before the motion compensated is carried out to conduct interference calculating.

Description

technical field [0001] The invention belongs to the field of synthetic aperture radar (SAR) signal processing, in particular to the fields of airborne SAR motion compensation and SAR interferometric height measurement. Background technique [0002] Motion compensation is a key technology in airborne SAR data processing. Due to the influence of the airflow, the carrier aircraft deviates from the ideal horizontal and straight-line flight state. It needs to use motion compensation technology to compensate in the process of SAR imaging processing, so as to restore the coherence between SAR echoes and obtain a well-focused image with correct phase information. SAR complex image. Conventional motion compensation method (reference [1]: A.Moreira and Y.Huang, "Airborne SAR processing of highly squinted data using a chirp scaling approach with integrated motion compensation", IEEETransactions on Geoscience and Remote Sensing, vol.32, no.5, pp.1029-1040, Sept.1994) It is necessary t...

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Problems solved by technology

This method does not require the use of external terrain elevation data, but compared with the traditional compensation method in which the two channels are compensated according to their respective reference trajectories, when the two channels are compensated according to the same reference trajectories, it will inevitably lead to a certain channel (or both at the same time) Channel) motion error margin increases, which in turn leads to a decrease in motion compensation accuracy, which limits the practical application of this method

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