LOW ELEVATION SENSITIVE GPS ANTENNA WITH MULTIPATH SUPPRESSION

ADROIT SYSTEMS, INC. PROPOSES TO DESIGN A NEW ANTENNA FOR A DIFFERENTIAL GPS (DGPS) BASE RECEIVER IN PHASE I, AND TO PROTOTYPE AND TEST THIS ANTENNA IN PHASE II. THIS NEW ANTENNA WILL INCORPORATE OPTIMUM LOW ELEVATION GAIN AND MULTIPATH SUPPRESSION TO ALLOW THE TRACKING OF SATELLITES AT ELEVATIONS FROM THE HORIZON TO FIVE DEGREES. AT ALL ELEVATIONS, THE ANTENNA WILL MINIMIZE ERRORS DUE TO MULTIPATH, REDUCE THE POSSIBILITY OF CARRIER CYCLE SLIPS, AND IMPROVE CODE TRACKING BY INCREASING THE CODE TO NOISE RATIO. ADROIT WILL ANALYZE AND SIMULATE MULTIPATH IN A DGPS SYSTEM TO DERIVE REALISTIC MULTIPATH AND GAIN REQUIREMENTS FOR THE ANTENNA. MICROWAVE LINK ANALYSIS WILL ALSO BE USED TO DERIVE ACCURATE REQUIREMENTS. SEVERAL GPS ANTENNAS, WITH THEIR GROUND PLANES AND FEED NETWORKS, WILL BE DESIGNED. THESE MULTIPLE DESIGNS WILL ALLOW SIMULATION OF ALTERNATE METHODS TO ACHIEVE THE ABOVE DESIGN GOALS. THE CANDIDATE ANTENNAS WILL BE EVALUATED ON THEIR SIMULATED PERFORMANCE IN A DGPS SYSTEM. IN THE FINAL REPORT FOR PHASE I, ADROIT WILL RECOMMEND TO THE COAST GUARD, BASED ON PERFORMANCE AND COST, THE BEST DESIGN FOR PROTOTYPING.