CCSDS recommendation on lossless data compression: the ESA contribution

Every year, due to more sophisticated sensors and more powerful high data rate instruments, the data collected by new satellites is constantly growing and leading to higher and higher downlink bandwidth demand. As it is not foreseeable an increase in the downlink bandwidth allocation (both for infrastructure reasons and spectrum allocation), satellites have to improve on-board data reduction and data encoding techniques. A lossless compression technique guarantees full reconstruction of the original data without incurring any data distortion and is particularly useful when data integrity cannot be compromised. In the decompression processes the original data are reconstructed by restoring the redundancy removed during the compression phase. The Consultative Committee for Space Data Systems (CCSDS) has recently issued a Recommendation for lossless data compression selecting the Rice algorithm as lossless data compression algorithm. The paper reports on the ESA contribution to CCSDS lossless data compression by presenting the activities and products performed both at ESTEC and ESOC. It deals first with the software model of Rice algorithm, which has been developed, internally at ESTEC. Then it presents the ongoing hardware implementation (ASIC) of the Rice algorithm. Such an ASIC is able to interface the virtual channel assembler and the virtual channel multiplexer components, well known by spacecraft designers and implementers. Finally the strategy adopted in the design of the CCSDS-Rice decompression software library to produce a flexible and efficient decompression tool for packetized and “raw” compressed data is presented