Combination of Space Geodetic Techniques with Clock Ties and Atmospheric Ties (COCAT) (P10)

P10 aims at improving the International Terrestrial Reference Frame (ITRF) in multi-technique combination via exploiting advanced atmospheric modeling strategies and atmospheric ties at global co-location sites with an emphasis on the novel clock strategies and clock ties at the Geodetic Observatory Wettzell (GOW).

The realization of the International Terrestrial Reference System, i.e. the ITRF, is based on the combination of Global Navigation Satellite Systems (GNSS), Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR), and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS). The multi-technique combination depends on various ties providing links between these techniques. Currently, only global ties (Earth Orientation Parameters, EOP) and local ties (station coordinates) are used. While local ties are fundamental for the combination, the accuracy and availability thereof are insufficient. Due to the discrepancies between different techniques, the limited availability and accuracy of ties, and the deficiencies in the combination strategies, the current ITRF accuracy still does not meet the accuracy requirement of 1 mm and 0.1 mm/yr, which is important for the monitoring of global sea level and climate change.

Due to the strong correlation between atmospheric delay, clock, and station coordinate estimates, improving the modeling and parameterization of atmospheric and clock parameters can enhance ITRF. P10 exploits the advanced modeling of atmospheric delay at global geodetic stations and employs the atmospheric ties at global co-location sites. P10 also investigates the inter- and intra-technique clock performances using the calibration data obtained from the novel clock technology, and exploits clock ties in the multi-technique combination. Working closely with other projects within the RU, P10 will demonstrate the successful separation of clock, atmospheric delay, and station coordinates in multi-technique combination and the benefits in TRF determination.
 

Publications:

• Test1
• Test2