Cognitive UHF Radio for Enhanced GPS Crosslinks

ABSTRACT: The accuracy and robustness of the GPS satellite constellation is tied to the ability of the satellites to communicate among themselves via their crosslink intersatellite network to implement Autonav functionality and to propagate commands and updates from the ground control segment.The current UHF-based crosslink suffers in performance due to interference from terrestrial UHF spectrum users, and the GPS constellations status as a secondary spectrum user.Application of innovative spectrum sensing techniques combined with efficient frequency-agile spectrum allocation protocols can make optimal use of current UHF frequencies without generating interference for primary spectrum users.Emerging digital radio frequency (RF) technologies, including latest space-capable field programmable gate arrays (FPGAs) and wideband data converters, can be leveraged to implement this dynamic spectrum access capability affordably in a small size, weight, and power footprint.Trident Systems (Fairfax, VA) proposes to leverage our strong background in programmable FPGA-based wideband digital RF transceivers, advanced self-forming data networks, and space-oriented architectures to develop a Dynamic Spectrum Crosslink Transceiver (DSCT).With support from key industry partners, Trident will implement a DSCT prototype capability through a comprehensive Phase I program of requirements analysis, modeling and simulation, and preliminary design, followed by prototype implementation in Phase II.; BENEFIT: The successful implementation of the Dynamic Spectrum Crosslink Transceiver will enable a more robust crosslink capability for current- and next-generation GPS satellites without requiring complete replacement of UHF-based RF signal chains and antennas.This will in turn lead to more accurate and reliable autonomous navigation performance of the GPS constellation, as well as more reliable propagation of command segment updates.Tridents modular approach to DSCT implementation will also make the proposed solution applicable to alternate crosslink frequency bands and RF front ends, as well as other space-based data communications network applications requiring high reliability and high performance.