Magellan ephemeris improvement using synthetic aperture radar landmark measurementsA technique is described for measuring the positions of landmarks in multiple SAR images of the surface of Venus taken aboard the Magellan spacecraft. These measurements are then used to improve the spacecraft orbit estimate. The Venus-fixed coordinates of the landmarks are also estimated, as are the low-order coefficients of the gravitational field. Sample results are shown for five-orbit and 13-orbit data arcs using hundreds of landmark measurements. Reasonably good fits to the data are obtained for the short-arc solutions, while the data fits over long arcs are poorer, possibly due to higher-order uncertainties in the gravitational field. A comparison of post-fit orbit uncertainties shows that the SAR data significantly improves the orbit estimate.
Document ID
19920060678
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Chodas, Paul W. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Wang, Tseng-Chan (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Sjogren, William L. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Ekelund, John E. (JPL Pasadena, CA, United States)