Satellite-borne radar imaging parameter online estimating method based on Kalman filtering

Abstract

The invention discloses a satellite-borne radar imaging parameter real-time online estimating method based on Kalman filtering. Main ideas of the method are as follows: an earth inertial coordinate system, an earth fixed coordinate system, a satellite orbit coordinate system, a satellite track coordinate system and a satellite fixed coordinate system are established; a conversion relation betweenthe earth fixed coordinate system and the earth inertial coordinate system is obtained, a conversion relation between the satellite orbit coordinate system and the earth inertial coordinate system isobtained, and a conversion relation between the satellite track coordinate system and the earth inertial coordinate system is obtained; a measurement equation of a satellite at k moment is established, Kalman filtering is carried out, and a position vector of the satellite in the earth inertial coordinate system at k+1 moment is obtained; and a wave beam center directional vector of a radar antenna and a point target are determined, a vector of a slant distance between the phase center of the radar antenna and the point target at the k+1 moment is calculated, and then the newest distance moment t0 and a B parameter are calculated, the B parameter being a satellite-borne radar imaging parameter real-time online estimating result based on Kalman filtering.

Description

technical field [0001] The present invention relates to the technical field of spaceborne radar, in particular to a real-time online estimation method of spaceborne radar imaging parameters based on Kalman filter, aiming at arbitrary eccentricity orbit and elliptical earth model, and suitable for spaceborne synthetic aperture radar (SAR) Imaging processing provides the key parameters needed. Background technique [0002] At present, space-borne SAR imaging technology is developing towards high-resolution and multi-mode. The azimuth resolution of the US "Lacrosse" space-borne SAR is better than 1m, while the SAR-Lupe launched by German DLR in early 2007 can reach a high resolution of 0.5m. [0003] At present, the more mature spaceborne SAR imaging model is the equivalent airborne linear orbit model with corrected velocity, that is, the side-looking spaceborne SAR is equivalent to the airborne linear orbit model, but the velocity is replaced by the equivalent velocity, and th...

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Problems solved by technology

For the new-generation spaceborne SAR system with high resolution and wide swath, the mismatch error caused by the equivalent airborne linear orbit model increases, and even fails in extreme cases; the traditional imaging processing method uses clutter l

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