Category: News of the other missions

The Doris instrument onboard Cryosat-2 was switched on 9 April. Few hours after the launch, the first data show good results with only small incertitudes on the orbit determination.

The Doris instrument onboard Cryosat-2 was switched on 9 April, few hours after the launch, and before the satellite has reached its final orbit. The Doris receiver detects and measures the Doppler shift on signals broadcast from the terrestrial beacons, put all over the world. By measuring very accurately the orbit determination, the Doris system has become indispensable to meet the quality requirements on the altimetric measurement. The use of Doris coupled with Diode navigator for locating the satellite on orbit in real time is also featured on Cryosat-2 but with more, and for the first time, the possibility of helping to maintain the satellite's position. The first data performed by the Doris system show good results on the orbit determination. During these first few days, the quality index shows small incertitudes on the orbit determination and is always below the maxima thershold.

Quality index of the orbit determination made by the Doris system on Cryosat-2 for the few days after the launch. Credits Cnes/Ssalto.

Further information:

• Missions: <link internal-link>Cryosat-2
• <link internal-link>Doris: principle, system, applications
• <link http: www.esa.int specials cryosat index.html _blank external-link-new-window>Cryosat-2 on Esa's website