Global Positioning Satellite (GPS) Receiver Test Bed Development

"The proposed Phase II program will develop a prototype for thedynamic simulation/generation of GPS signals from the antennas ona reentry body (RB) during reentry. A prototype of the GPSReceiver Test Bed System will developed and delivered that willproduce GPS signals that are equivalent to those received on anRB during the mid-course segment of the trajectory into the endo-atmospheric segment of the trajectory until there is severe GPSsignal attenuation, e.g. > 60 dB, due to the reentry plasma. Thesystem will accept as input RB dynamic descriptors characterizingreentry conditions and generate GPS signals that will be theinput to a commercially available GPS receiver. Testing theperformance of such a receiver for reentry trajectories andperturbations of the GPS signal due to plasma attenuation andgroup delay versus RB roll angle and angle of attack will beperformed. Hence, comparisons will be between the actualsimulated trajectory and the trajectory determined by thecommercial GPS receiver using the output signal from the GPSReceiver Test Bed System to evaluate candidate GPS receiversprior to flight tests. The documented prototype will bedelivered to the Navy at the end Phase II program.BENEFITS: The successful completion of the proposed Phase II program will greatly enhance the ability to perform hardware-in-the-loop ground testing of candidate GPS receivers that might be used on NavyRBs. Physical Sciences Inc.'s GPS Receiver T