SATELLITE DATA LINK STANDARDS*

Abstract

Flexibility and survivability of Space Communications dictate the interoperability of communication links between as many satellites as feasible. Interoperability increases survivability by providing alternate paths. Interoperability also improves total system reliability and cost effectiveness, and it permits a flexible, distributed communications architecture to evolve. To implement this approach, functional satellite data link standards are needed to pull together mission data relay, communications, and tracking, telemetry and command (TT&C) requirements so that they can be satisfied by a common link design. The basic requirement which unifies these diverse users is their need for uplink jamming protection and scintillation resistance (in a perturbed atmosphere) at low (75 bps to 19.2Kbps) data rates. While the downlink and crosslink requirements are more diverse, they do not constitute major drivers of the standard. This paper describes Space Division’s standardization effort, the links to be standardized, the parameters that must be defined and an evolutionary implementation approach. The first satellite-ground links to be standardized will use 44/20 GHz with wideband spreading for jam resistance, while the crosslinks will use 60 GHz to avoid terrestrial jamming. Key issues are discussed, such as the conflicting requirements between TT&C and communications and the tradeoffs between minimum designs and flexibility.