GPS Radio Occultation with TanDEM-X
- Flying in formation, TanDEM-X and TerraSAR-X
- © DLR
The GPS radio occultation data of the German TanDEM-X
 satellite are analysed and globally distributed vertical
atmospheric profiles (bending angles, refractivity, temperature, water
vapor) are derived and provided for the international user community.
TanDEM-X  was launched June 21, 2010 and forms together with
TerraSAR-X  (launch July 15, 2007) an unique tandem-satellite
The close proximity of the TerraSAR-X and TanDEM-X satellites offers an unique opportunity; the estimation of the precision of GPS atmospheric soundings. In essence, if the receivers aboard TerraSAR-X and TanDEM-X track the same setting (or rising) GPS satellite (signals traverse virtually the same atmospheric column) then the differences in the retrieved atmospheric products measure the degree of the reproducibility of the GPS RO technique. In addition the twin satellite configuration offers another opportunity: the ability to study the sensitivity of retrieved atmospheric products w.r.t signal tracking parameters.
 Zus, F., G. Beyerle, L. Grunwaldt, S. Heise, G. Michalak, T. Schmidt and J. Wickert, Sensitivity of GPS radio occultation atmospheric soundings w.r.t. open loop signal tracking parameters, submitted to Advances in Space Research, 2013.