Precision Orbit Determination For The Current Jason Missions Using GPS
Event: 2016 Ocean Surface Topography Science Team Meeting
Session: Precision Orbit Determination
Presentation type: Type Oral
Contribution: PDF file
We will examine the current state of the art for precision orbit determination (POD) with the two current Jason spacecraft, Jason2 and Jason3 using GPS data. With the recent launch of Jason3, January 2016, it is important to assess the performance of the GPS on-board receiver. We will present basic receiver metrics and compare them to Jason2. A new launch or a GPS antenna swap, as we had on Jason2, requires calibration of the antenna with flight data. We have calibrated the Jason3 flight antenna and will present an analysis of the calibration. For both Jason2, and Jason3 we plan to release a time series of the GPS determined orbits. For Jason2, this will be an extension of the time series released before the 2015 OSTST meeting. Orbit quality and error assessment will include comparisons with other POD analysis centers and will include both time series and geographical differences. Although these differences are quite small now, their nature allows us to infer possible remaining errors in the POD system. For instance, the difference JPL 2015 release with the GDRE, shows a distinct pattern on the globe when fit to an annual, with a peak amplitude of the radial difference of about 3.2 mm in the South Pacific. The pattern suggests some differences in the realization of the geocenter. The usual tests of altimeter cross-overs will be presented as an independent measure of orbit accuracy. Altimeter differences between Jaons2 and Jason3, during the tandem mission will be examined for systematic POD errors.