Besides our IGS GNSS activities our group at ESOC is also heavily involved in LEO POD using DORIS, SLR, PRARE, and Altimetry observations, in particular for the ESA missions ERS-1 and 2 and Envisat. We do, however, have concrete plans to become a reprocessing Analysis Center for both the IDS and the ILRS. For the IDS a first 1-year solution is currently being generated. Below some interesting results from our DORIS activities.
DORIS Phase Center Variations
In GNSS we have had significant issues with the location of the receiver and transmitter phase center position. DORIS, also being a microwave technique, suffers from the same problems. The lessons learned in GNSS in this area are very useful for the DORIS technique. The top two figures below show the residuals of the DORIS observations as function of azimuth and elevation for two DORIS stations. One station, SCRB, located around the equator, the other one, FAIB, near the North-Pole. The bottom two figures show the residuals for the Envisat transmitting antenna, once in colour and once in black and white. In all cases some clear signals may be observed which are most likely caused by the phase center variations of the DORIS antennas.
Orbit Prediction Tests
Improvement of ESOC IGS Contributions
The two figures below show the improvement of the ESOC IGS contributions. The top figure shows it for the ESOC Rapid orbits. The ESOC rapid products are based on our new software Napeos starting with the products of day 2 of GPS week 1469. The bottom figure shows the improvement for our ESOC Final clocks. The ESOC final products are based on our new software Napeos starting with GPS week 1463. In both cases a significant improvement of the results may be observed.
ESOC has the ambition to remain amongst the
“best in class” in the IGS and in addition
contribute significantly to the IDS, ILRS, and IVS!