GPS Reconstitution

This proposal describes a plan to design and develop techniques to utilizing legacy GPS receiver based systems, in the even of failures in GPS signals. A variety of situations are considered and we propose to perform simulations under thesesituations, where diverse mitigation schemes are needed. The mitigation schemes include satellite and airborne devices, rocket launched system as well as ground based systems. Generation of GPS replacement signals involve issues such as near-far problem,platform dynamics, frequency-offset, spoofing, pulsed operation, time synchronization, etc.We propose to use versatile software and hardware based signal simulators and GPS receivers developed by us to model these diverse conditions and situations. The modeling tools can be easily reconfigured for simulation and later be used for real-timedemonstration. During Phase I, we investigate different situations and provide performance characteristics of legacy GPS receivers under the different situations. Finally, we demonstrate the validity by performing live demonstration using our hardwareunits. Such system will find numerous applications in DoD and civilian sectors. Applications range from Pseudolites, Simulator development, various GPS development efforts and so-on.