Abstract's details
Doris/Diode on-board Jason-3 and Sentinel-3 : real-time estimations for pole coordinates and USO frequencies
CoAuthors
Event: 2014 IDS Workshop
Session: Network and constellation: status and evolution
Presentation type: Type Oral
Contribution: not provided
Abstract:
DORIS on-board software has been much improved since the first launches of DORIS carrier satellites (SPOT2, 1990, then TOPEX, 1992). In 1998, SPOT4 flew the first version of DIODE on-board orbit restitution software for a successful probatory experiment. In the recent years, new versions of DORIS software including DIODE "navigator" have been designed in preparation to Jason-3 and Sentinel-3 flights, expected in 2015.
One peculiar characteristic of the last version (called DGXX-S v4_00) is the computation of new Real-Time products :
- Pole coordinates estimates computed by the on-board software : DIODE has been refined and is now able to produce a 1 mas estimation in real-time. This data will be interesting to produce a Near-Real-Time estimation, or to initialize longer delay adjustments. When Jason-3 and Sentinel 3A will be in orbit, ground mixing of the results of 2 satellites will help refining these estimates.
- Frequency estimates also computed by the On-Board Software for on-board and on-ground DORIS USOs : T2L2 experiment on Jason-2 has allowed improvement and validation of DORIS frequency restitution results. A 10-12 accuracy is achieved today, and this will be a great help for precise monitoring and control of DORIS integrity of the whole beacon network. Each telemetry flow coming from Jason-3, Sentinel-3A and the following satellites, will provide NRT estimates of the whole beacon network frequencies. Easy then to control them in an automatic system, leading to a red light if anything surprising occurs on any beacon. These information coulds also be used by ground programs as initialisation values in their processing.
Both Jason-3 and Sentinel-3 projects have authorised additional downlink in the telemetry of this information. In the future, other on-board estimates may be studied : tropospheric or ionospheric quantities deduced from the DORIS measurement could be downloaded using the same technique.
One peculiar characteristic of the last version (called DGXX-S v4_00) is the computation of new Real-Time products :
- Pole coordinates estimates computed by the on-board software : DIODE has been refined and is now able to produce a 1 mas estimation in real-time. This data will be interesting to produce a Near-Real-Time estimation, or to initialize longer delay adjustments. When Jason-3 and Sentinel 3A will be in orbit, ground mixing of the results of 2 satellites will help refining these estimates.
- Frequency estimates also computed by the On-Board Software for on-board and on-ground DORIS USOs : T2L2 experiment on Jason-2 has allowed improvement and validation of DORIS frequency restitution results. A 10-12 accuracy is achieved today, and this will be a great help for precise monitoring and control of DORIS integrity of the whole beacon network. Each telemetry flow coming from Jason-3, Sentinel-3A and the following satellites, will provide NRT estimates of the whole beacon network frequencies. Easy then to control them in an automatic system, leading to a red light if anything surprising occurs on any beacon. These information coulds also be used by ground programs as initialisation values in their processing.
Both Jason-3 and Sentinel-3 projects have authorised additional downlink in the telemetry of this information. In the future, other on-board estimates may be studied : tropospheric or ionospheric quantities deduced from the DORIS measurement could be downloaded using the same technique.