DORIS APPLICATIONS

DORIS instrument is used for different applications such as:

		Precise (centimetric) orbit detemination for altimetry
		Precise positioning of ground Beacons (DORIS is one of the IERS technics) Earth pole motion monitoring ITRF contribution Tectonic
		Models improvement: gravity field, geoid
		On-board orbit determination
		On board time tagging w.r.t. TAI time scale

Missions with a DORIS instrument

DORIS is part of the scientific payload, it is a primary sensor for the subdecimetric orbit determination which is required to achieve the large scale ocean monitoring goal of this mission. It was early decided to get an in-flight validation of DORIS before TOPEX/POSEIDON. This was done by flying DORIS on board the SPOT2 earth observation satellite (launched in 1990) as a passenger experiment.

Recognising the ability of the system to provide precise positioning of ground beacons, DORIS was approved for flying on board SPOT3 (launched in September 93) and SPOT4 for this mission.
In the case of SPOT4 a real time on board orbit determination capability, called DIODE, has been added to DORIS to provide SPOT images users with satellite ephemeris.
The Doris System has also been approved by the European Space Agency to determine the precise orbit of the ENVISAT-1 Satellite to study Earth Environment.
New DORIS on board instruments are embarked on JASON-1 (TOPEX-POSEIDON follow on mission) and on SPOT5 satellite platforms. These new instruments (called Miniaturised 2nd Generation) are similar to the DORIS/ENVISAT on board instrument in terms of functions and performances, but with improved Mass / Volume / Consumption characteristics, a more integrated design, and a wider use of digital processing techniques.

Current generation of instruments called DGxx fly on board JASON-2 (JASON-1 follow-on), on board CRYOSAT-2 (European Space Agency ice monitoring mission), and will fly on board SARAL/AltiKa (the franco-indian ocean altimetry mission in Ka-band).
DGxx instruments are equiped with 7 bifrequency channels to allow simultaneous tracking of up to 7 beacons to fullfil the needs of the International Doris Service.
Such receivers are also envisoned on board HY-2A (chinese ocean observation mission) and latter on board JASON-3.