Interferometric calibration method and system for a space-based interferometric imaging radar altimeter

Abstract

The invention relates to a method and system for calibrating interference of a space-based interferometric imaging radar altimeter. The method comprises the following steps: determining the radar viewing angle of each pixel point of a reference target according to the altitude information of the reference target as well as rail and slant distance parameters acquired by the space-based interferometric imaging radar altimeter; performing polynomial fitting on the spatial variation relation between the unrapping phase and the radar viewing angle; determining the sensitivity of the unwrapping phase and the slant distance on the radar viewing angle separately; determining the length and the inclination angle of a base line; and determining interferometric phase offset. The system comprises a radar viewing angle calculation module, a fitting coefficient calculation module, a sensitivity calculation module, an interferometric base line determining module and an interferometric phase offset determining module. Estimation of the interferometric base line and the interferometric phase offset can be separated by fitting and estimating the sensitivity of the unwrapping phase on the radar viewing angle, so that the three parameters such as the length of the base line, the inclination angle of the base line and the interferometric phase offset, can be completely estimated.

Description

technical field [0001] The invention belongs to the field of interferometric calibration of an interferometric imaging radar altimeter, in particular to an interferometric calibration method and system for a space-based interferometric imaging radar altimeter. Background technique [0002] A new type of radar altimeter developed in recent years, that is, space-based interferometric imaging radar altimeter, can obtain the average sea surface height value in a large area, with a spatial resolution of 100 meters and an observation swath of 50 to 100 kilometers. Compared with the traditional sub-satellite point radar altimeter, its spatial resolution and temporal resolution have been greatly improved. But to apply this technique, precise interferometric calibration is an essential key step. Interferometric calibration enables precise on-orbit measurement of interferometric parameters of space-based interferometric imaging radar altimeter, including baseline length, baseline inc...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is: the influence of the curvature of the earth is not considered in the existing technical solutions, and the estimation of the interference phase offset cannot be realized due to the "ill-conditioned solution" or the failure of the iterative algorithm to converge when estimating the parameters

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