UST-Lite Direct Waveform Sampling Software-Defined Radio for Spaceflight Applications

The Universal Space Transponder (UST) product line developed at the Jet Propulsion Laboratory offers Software-Defined Radio (SDR) solutions for various spaceflight applications. The UST-Lite is the latest product offering that provides a more miniaturized radio package with cutting-edge processing capabilities and features by taking advantage of recent advancements in digital processing and sampling technology. Parts selection and design guidelines follow JPL flight practices suitable for missions with high reliability requirements (e.g., Discovery or New Frontiers class), but the radio could also be adapted for use on SmallSat missions given its reduced power consumption, volume, and mass compared to other JPL radios. The main digital processor is implemented with a Swift Processor Module (SPM) developed in collaboration with JPL's Common Instrument Electronics task. The SPM uses a Kintex UltraScale FPGA (XQRKU060) with two mezzanine card slots to house application-specific circuit cards such as digital samplers, interface electronics, or additional processors. The UST-Lite uses mezzanine cards with high-speed digital samplers to directly sample and synthesize waveforms. With such direct waveform sampling approach, component counts can be drastically reduced while avoiding the use of baseband and intermediate frequency (IF) waveforms. The higher digital processing capability, coupled with expandable access to multiple high-speed samplers, allow the UST-Lite to support up to four simultaneous communication bands. The first version of the UST-Lite is targeted at supporting a quad-band link: S/Ka-band proximity, and X/Ka-band Earth communications simultaneously. This paper will provide an overview of the UST-Lite quad-band radio and its key design features, as well as optional configurations that are adaptable and configurable for mission needs. Test results from the prototype radio will be presented, as well as potential design modifications being considered for the next design revision. The current plan is to achieve TRL-5/6 by mid 2023.