Flexible coherent digital transceiver for low power space missions

A flexible coherent digital transceiver architecture has been developed by the APL in order to enable mission specific performance tailoring while maintaining modularity and minimizing program-incurred cost and risk. The new transceiver architecture is based on the heritage X-band transceiver system that is currently integrated into the New Horizons spacecraft. Using this new architecture, a low power, coherent, X-band digital transceiver has been made that meets the requirements for two-way Doppler tracking. The new transceiver contributes less than 0.01 mm/s to the Doppler velocity error measured over a 60-second interval in coherent mode. Secondary power consumption is 2.8 W in the uplink-only mode of operation including the reference oscillator. Transceiver designs on the TIMED, CONTOUR, and New Horizons spacecraft were noncoherent, which required downlink telemetry in order to support two-way Doppler tracking (Jensen, 1999). The addition of a coherent capability allows this new architecture to be used on missions where carrier-only Doppler tracking is desired. This paper provides a description of the new transceiver architecture and its demonstrated performance