07 - Systems, Subsystems and Equipment
ATTITUDE ESTIMATION USING KALMAN FILTERING FOR SPACEBORNE SAR SYSTEMS
Y. Ding¹, D. Xu¹, Y. Li¹, Z. Fang¹, T. Chen¹, H. Zhang, Airforce Engineering University, China; B. Chen, Shanghai University, China; ¹Aviation Industry of China (AVIC), China
Doppler parameters of spaceborne Synthetic Aperture Radars (SAR) depend on the orbit elements and the direction rnof radar antenna pointing. Since satellite attitudes have impact to antenna pointing, accurate estimates of attitude rnerrors are crucial to derive SAR Doppler parameters. To system design perspective, Kalman filtering mayrncontinuously track yaw and pitch based on the measurements of Doppler centroid and the information obtained from rnorbit state vectors. The algorithms being proposed are suitable to both onboard and ground station. We show, by rncomputer simulations, that Kalman filtering may take advantages to provide attitude errors and attitude rates with rnsuperior precision. As a consequence, accurate Doppler centroid and Doppler frequency rate may be estimated by rnexplicit calculation from the spacecraft ephemeris.