Geometric cross-calibration method and system for spaceborne SAR images

Abstract

The invention relates to a geometric cross-calibration method and system for spaceborne SAR images. The method comprises the steps of step 1), establishing an atmospheric delay correction model of images to be calibrated; step 2) establishing a geometric calibration model of the images to be calibrated; step 3), selecting pairs of points with the same name from the images to be calibrated and reference images; step 4, according to imaging time of the images to be calibrated, using global atmospheric data provided by NCEP and ionospheric electron content distribution data provided by the European Orbit Determination Center (CODE), through the atmospheric delay correction model established in the step 1), calculating atmospheric delay correction values of the image to be calibrated; step 5),substituting the several pairs of points with the same name obtained in step 3) and the atmospheric delay correction values obtained in step 4) into the geometric calibration model established in step 2) to complete geometric calibration parameter solution. The method can achieve the normalization and short-period geometric calibration of a SAR satellite, do not need to arrange targets in advanceon the ground, and greatly save manpower and financial cost.

Description

technical field [0001] The invention relates to a geometric calibration method, in particular to a spaceborne SAR (Synthetic Aperture Radar) image geometric cross calibration method and system. Background technique [0002] Geometric calibration refers to the use of high-precision ground control data to accurately calibrate the geometric parameters of on-board imaging, which is of great significance for improving the geometric accuracy of satellite images. [0003] The traditional geometric calibration method relies on the high-precision control data of the geometric calibration field. Therefore, after the satellite is launched, it is necessary to collect images of the calibration field area to complete the geometric calibration. Only when the satellite successfully obtains the image of the calibration field area can it be carried out Geometric calibration, which cannot meet the needs of satellite normalization and rapid geometric calibration. In addition, the number of fix...

AI Technical Summary

Problems solved by technology

[0003] The traditional geometric calibration method relies on the high-precision control data of the geometric calibration field. Therefore, after the satellite is launched, it is necessary to collect images of the calibration field area to complete the geometric calibration. Only when the satellite successfully obtains the image of the calibration field area can it be carried out Geometric calibration, which cannot meet the needs of satellite normalization and fast geometric calibration

In addition, the number of fixed and available geometric calibration fields is too small, and the frequency of satellite shooting of calibration fields is too low, so it is impossible to use calibration technology to monitor changes in geometric imaging parameters on the satellite, resulting in a decrease in the accuracy of satellite products

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