C-Band station coordinate determination for the GEOS-C altimeter calibration area

Dynamical orbital techniques were employed to estimate the center-of-mass station coordinates of six C-Band radars located in the designated primary GEOS-C radar altimeter calibration area. This work was performed in support of the planned GEOS-C mission (December, 1974 launch). The sites included Bermuda, Grand Turk, Antigua, Wallops Island (Virginia), and Merritt Island (Florida). Two sites were estimated independently at Wallops Island yielding better than 40 cm relative height recovery, with better than 10 cm and 1 m (relative) recovery for ϕ and λ respectively. The tracking data used in this analysis were taken during 1969 when the radars tracked the GEOS-II transponder. The data used were exclusively that from the estimated sites and included 18 orbital arcs which were less than two orbital revolutions in length, having successive tracks over the area. In all, over 120 passes of data were used. Range biases were estimated. Error analysis and comparisons with other investigators indicate that better than 2 m (1 σ) relative recovery has been achieved at all sites. The techniques employed here, given their independence of global tracking support, can be effectively employed to improve various geodetic datums by providing very long and accurate baselines. C-Band data taken on GEOS-C should be employed to improve such geodetic datums as the European—1950 using similar techniques.