Study On Spaceborne Radar Altimeter Error Analysis And Calibration Technology

Radar altimeter is one of the most important microwave sensing instruments. Error analysis is one of the key issues in radar altimetry. various kinds of error sources in altimetry is investigated, especially instrument errors and tracking errors. An error budget is then brought out finally. Besides, some issues on altimeter in-orbit calibration are discussed.The major innovation points are as following:(1) The instrument errors are analyzed thoroughly, especially those in the IF and digital chains, and some instructive results are given.(2) Three classes of echo tracker algorithms are investigated, the error discriminative curve is derived in ASG algorithm, and the noise arise from the gate tracker is computed. The correlations of the echoes are investigated, and an approach of decorrelation is derived to extend the applicability of the tracker algorithms.(3) An algorithm to retrieve the attitude angle is discussed and the accuracy of attitude angle estimation is derived.(4) The acceleration lag bias in height estimation is derived and an innovative algorithm to compensate the bias is introduced.(5) The ionospheric dispersion error in dual-frequency altimetry is investigated.(6) The in-orbit calibration of the altimeter system is considered, some engineering parameters are presented, and the relative errors are analyzed.