A reconfigurable, radiation tolerant S-Band radio for space use

Southwest Research Institute (SwRI) is developing a reconfigurable, radiation tolerant, communication system that addresses the needs for low-cost, quick turn spacecraft, as well as the reliability and connectivity required in harsh radiation environments of higher orbit systems. The core of such a Flexible Communication Platform (FCP) centers on a Software Defined Radio (SDR) architecture providing S-Band (2 GHz) communications. The Digital Processing Unit (DPU) fits in a 1U form factor and forms half of a two-slice approach (RF front-end is on a separate slice). The architecture of the DPU is based on the Virtex-4, an SRAM-based FPGA from Xilinx. SRAM-based FPGAs, however, have significant limitations in spacecraft systems due to radiation susceptibility of the FPGA programming cells. SwRI chose to implement a combination of triplicated logic (TMR) and Configuration Memory Scrubbing, specifically in an external RAD-Hard device, to mitigate radiation effects on the system. The flexible design of the DPU allows rapid integration into multiple target mission architectures. When coupled with the RF front-end, the FCP is capable of communicating from LEO and MEO orbits using a variety of wideband signals and protocols.