2019-03-26 16:44:06.0 [sritz] update WeightedRelation (Platform-Instrument); update WeightedRelation (1);
2019-03-26 16:43:29.0 [sritz] insert WeightedRelation (id: null related concept uuid: 41163801-6aac-43e5-aed7-9f52613a6a73 relationship type: null relationship value: null generated by: null);
2019-02-22 14:20:26.0 [mmorahan] update Resource (image); insert WeightedRelation (id: null related concept uuid: 5449d87b-5573-450f-8acb-2fdfeab3c8ce relationship type: null relationship value: null generated by: null);
Radio
[Source: ESA/Earthnet Online, http://envisat.esa.int/instruments/doris/ ] The Doppler Orbitography and Radio-positioning Integrated by Satellite instrument is a microwave tracking system that can be utilized to determine the precise location of the ENVISAT satellite. Versions of the DORIS instrument are currently flying on the SPOT-2 and Topex-Poseidon missions. DORIS operates by measuring the Doppler frequency shift of a radio signal transmitted from ground stations and received on-board the satellite. The reference frequency for the measurement is generated by identical ultra-stable oscillators on the ground and on-board the spacecraft. Currently there are about 50 ground beacons placed around the globe which cover about 75% of the ENVISAT orbit. On board measurements are performed every 7 - 10 seconds. Precise Doppler shift measurements are taken using an S-band frequency of 2.03625 GHz, while a second VHS band signal at 401.25 MHz is used for ionospheric correction of the propagation delay. On the ground, DORIS data is used to create precise orbit reconstruction models which are then used for all satellite instruments requiring precise orbit position information. In addition, DORIS operates in a Navigator mode in which on-board positioning calculations are performed in real-time and relayed to the ground segment. Group: Instrument_Details Entry_ID: DORIS Group: Instrument_Identification Instrument_Category: Earth Remote Sensing Instruments Instrument_Class: Passive Remote Sensing Instrument_Type: Positioning/Navigation Instrument_Subtype: Radio Short_Name: DORIS Long_Name: Doppler Orbitography and Radiopositioning Integrated by Satellite End_Group Group: Associated_Platforms Short_Name: CRYOSAT-2 Short_Name: ENVISAT Short_Name: JASON-1 Short_Name: OSTM/JASON-2 Short_Name: SPOT-2 Short_Name: SPOT-3 Short_Name: SPOT-4 Short_Name: TOPEX/POSEIDON Short_Name: SPOT-5 Short_Name: CRYOSAT End_Group Group: Spectral_Frequency_Information Wavelength_Keyword: Radio Number_Channels: 2 Channels Spectral_Frequency_Coverage_Range: 401.25 MHz and 2036.25MHz End_Group Online_Resource: http://envisat.esa.int/instruments/doris/ Online_Resource: http://www.aviso.oceanobs.com/en/doris/index.html Sample_Image: http://www.aviso.oceanobs.com/typo3temp/pics/98d5269f70.jpg Creation_Date: 2007-04-16 Group: Instrument_Logistics Data_Rate: 330 bps Instrument_Start_Date: 2002-01-15 Instrument_Owner: France/CNES End_Group Group: Instrument_Logistics Instrument_Start_Date: 1992-09-23 Instrument_Stop_Date: 2005-10-09 End_Group End_Group
DORIS