Optimization of Time Data Codification and Transmission Schemes: Application to Gaia
Gaia is an ambitious space observatory devoted to obtain the largest and most precise astrometric catalogue of astronomical objects from our Galaxy and beyond. On-board processing and transmission of the huge amount of data generated by the instruments is one of its several technological challenges. The measurement time tags are critical for the scientific results of the mission, so they must be measured and transmitted with the highest precision – leading to an important telemetry channel occupation. In this paper we present the optimization of time data, which has resulted in a useful software tool. We also present how time data is adapted to the packet telemetry standard. The several communication layers are illustrated and a method for coding and transmitting the relevant data is described as well. Although our work is focused on Gaia, the timing scheme and the corresponding tools can be applied to any other instrument or mission with similar operational principles.
Keywordsastrometry data codification optimization pipelined processing satellite communications telemetry
Unable to display preview. Download preview PDF.
- Bastian, U.: 2004, ‘Reference systems, conventions and notations for Gaia’, Technical note GAIA-ARI-BAS-003.Google Scholar
- Consultative Committee for Space Data Systems: 2000, ‘Packet telemetry’, CCSDS 102.0-B-5 blue book.Google Scholar
- Consultative Committee for Space Data Systems: 2002, ‘Time code formats’, CCSDS 301.0-B-3 blue book.Google Scholar
- De Bruijne, J.: 2003, ‘Gaia clock accuracy and stability’, Technical note GAIA-JdB-004.Google Scholar
- European Space Agency, Standards Approval Board for Space Data Communications: 1988, ‘Packet telemetry standard’, ESA PSS-04-106 Issue 1.Google Scholar
- Høg, E.: 2002, ‘Sampling for all magnitudes: Scheme C’, Technical note GAIA-CUO-113.Google Scholar
- Jordi, C., Babusiaux, C., Katz, D., Portell, J. and Arenou, F.: 2003, ‘Gaia: Instrument and satellite parameters’, Technical note GAIA-SWG-012.Google Scholar
- Pace, O.: 1998, ‘Clarification on the Probability of Frame Loss (PFL) in data transmission to ground’, Technical note SAG-OP-001.Google Scholar
- Portell, J., García-Berro, E. and Luri, X.: 2001, ‘Flux data codification: Proposals of simple codification schemes’, Technical note GAIA-BCN-001.Google Scholar
- Portell, J. et al.: 2002, ‘Payload data handling, compression and telemetry formatting’, Kick-off meeting of the Simulation Working Group of Gaia.Google Scholar
- Portell, J., García-Berro, E. and Luri, X.: 2004, ‘Timing and transmission schemes for Gaia’, Technical note GAIA-BCN-006.Google Scholar