All 2015 Content
Session
Technical Session VI: Ground Systems and Communications
Abstract
The HI-BEAM DVB-S2 high-speed modem has been reviewed to determine if it is suitable to deploy on a small LEO satellite for a spacecraft to ground data link at user rates up to 800 Mbps. DVB-S2 provides close to Shannon Limit performance using QPSK, 8PSK and 16APSK modulations and LDPC codes. The original design of the HI-BEAM modem was for an aircraft to ground data link. Examination of its radiation tolerance level (Total Dose = 5 krads) indicates it can only operate at the lower altitudes of a few 100 kilometers without additional radiation hardening/shielding. Mechanical and thermal tests indicate that the existing design should not require any substantial changes to meet the requirements for launch and on-orbit operations. In addition the use of the DVB-S2 Variable Coding and Modulation (VCM) should provide over a 50% greater throughput relative to constant coding and modulation (CCM) links.
Low-Cost, High-Speed Modems for Small LEO-to-Ground and LEO-to-LEO Data Links
The HI-BEAM DVB-S2 high-speed modem has been reviewed to determine if it is suitable to deploy on a small LEO satellite for a spacecraft to ground data link at user rates up to 800 Mbps. DVB-S2 provides close to Shannon Limit performance using QPSK, 8PSK and 16APSK modulations and LDPC codes. The original design of the HI-BEAM modem was for an aircraft to ground data link. Examination of its radiation tolerance level (Total Dose = 5 krads) indicates it can only operate at the lower altitudes of a few 100 kilometers without additional radiation hardening/shielding. Mechanical and thermal tests indicate that the existing design should not require any substantial changes to meet the requirements for launch and on-orbit operations. In addition the use of the DVB-S2 Variable Coding and Modulation (VCM) should provide over a 50% greater throughput relative to constant coding and modulation (CCM) links.
