Gravity model improvement for SEASAT

摘要: Analysis of the data from SEASAT altimeter, a 10-cm precision instrument, requires accurate knowledge radial position spacecraft for oceanographic applications such as study tides and ocean circulation well geodetic applications. Initial orbit determinations using best available force models gave errors approaching 5 m. The dominant source this error was gravity field model. Improvements in modeling were made by successively incorporating laser Unified S Band ground tracking data, GEOS 3 altimeter finally, data. With most recent model (a set spherical harmonic coefficients complete to degree order 36), ephemerides have been computed an orbital arc length 12 days with rms accuracy about 70 cm.