PDHT Solution with Modem for High Order Modulation Schemes (MHOMS)
- Paper number
IAC-07-B1.4.09
- Author
Mr. Mario Cossu, Alcatel Alenia Space Italia, Italy
- Coauthor
Mr. Michelangelo L'Abbate, Alcatel Alenia Space Italia, Italy
- Coauthor
Mr. Carlo Svara, Alcatel Alenia Space Italia, Italy
- Coauthor
Mr. Paolo Venditti, Alcatel Alenia Space Italia, Italy
- Coauthor
Mr. Rocco Novello, Alcatel Alenia Space Italia, Italy
- Coauthor
Mr. Alberto Ginesi, European Space Agency (ESA)/ESTEC, The Netherlands
- Coauthor
Ms. Monica Martinez Fernandez, European Space Agency (ESA)/ESTEC, The Netherlands
- Coauthor
Mr. Domenico Giancristofaro, Alcatel Alenia Space Italia, Italy
- Year
2007
- Abstract
In the frame of the Earth Observation missions, the on-board Payload Data Handling and Transmission (PDHT) is a fundamental payload aimed to on-board storage of scientific data acquired from embarked payloads (SAR, Optical Payloads, Infrared Payload), their formatting according to CCSDS Recommendations, the modulation, amplification and RF filtering and the data transmission to Ground Segment in X-band. The PDHT already developed are innovative both for the overall architecture, which resulted to be highly modular and reusable on other programs, and for the usage on commercial memory components; thanks to this approach the PDHT design takes full advantage from low cost memory technology, following the natural performance and size improvements induced by the personal computer market. The proposed PDHT is an evolution of the data handling equipment already designed, developed and delivered to different customers (1 flight model to MDA for Radarsat-2 program, 4 flight models to Italian Space Agency for COSMO SkyMed program) or in a development phase (as subsystem of SAR instrument to Korea Aerospace Research Institute for Kompsat-5 program). The downlink data rate appears as the “bottleneck” of an Earth Observation satellite; in fact, the information rate transmitted to ground has to comply with the narrow allocated transmission band (8025 MHz - 8400 MHz); moreover, to achieve an high performance link and reduce the transmitted power, Reed-Solomon coding is performed, introducing an overhead in the transmitted Transfer Frame and reducing the downloadable scientific data rate. Due to interference in the DSN band, the maximum scientific data rate is expected to be about 600 Mbps, transmitted through two orthogonal polarizations and available O-QPSK modulators; unfortunately, the application of “frequency-reuse” concept highly impacts on PDHT’s current architecture due to technological constraints on antenna implementation (high required XPD). One attractive “full European” solution, able to further increase the data rate, is the implementation of Adaptive Coding Modulation through MHOMS; performing the Serial Concatenation of Convolutional Codes (SCCC) and a selectable modulation schemes ranging from QPSK to 64APSK, MHOMS has demonstrated the capability to achieve up to 1Gbps of downlink data rate in X-Band and ensures an high adaptability on the link conditions (on ground G/T, atmospheric condition of the link). A preliminary analysis of a MHOMS based PDHT is provided, including impacts on current implementation, ground segment and communication standards and details on current MHOMS state-of-art; the MHOMS based PDHT’s expected performances are compared with current and future PDHT architecture.
- Abstract document
- Manuscript document
IAC-07-B1.4.09.pdf (🔒 authorized access only).
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