AuthorMacMedan, M. L.
AffiliationCalifornia Institute of Technology
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RightsCopyright © International Foundation for Telemetering
Collection InformationProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection.
AbstractChannel coding is a well-established method for improving the performance of a channel, or link, between space and earth. Until recently, the types of codes and their parameters were frequently tailored to optimize the performance of the data through a channel for a specific application. Furthermore, lack of coordination led to a situation where different developing bodies pursued slightly different schemes with essentially the same peformance. This resulted in a proliferation of coding schemes which inhibits interoperability (among centers as well as agencies) and cross support. Work has been done by two recently-established standards coordinating bodies, the NASA-ESA Working Group for Space Data Systems Standardization (NEWG) and the Consultative Committee for Space Data Systems (CCSDS), to standardize on a few highperformance codes for general applicability. These codes, which are described in the NEWG Telemetry Channel Coding Guideline (Reference 1), can provide up to 6.8 dB of coding gain. They may not be perfectly optimized for every mission, but they can, in most cases, provide satisfactory performance at low cost through amortization of development costs. This leads to affordable inter-center and inter-agency cross support, and cooperative missions. Error protection is similarly needed for telecommanding, and work has been under way in the CCSDS to establish a Telecommand Channel Coding Recommendation. Status of this work, and methods of synchronization and telecommand frame error protection, are discussed. This paper may also be of interest to other non-NASA space communication channel users.
SponsorsInternational Foundation for Telemetering