Performance Evaluation of GPS Augmentation Using Quasi Zenith Satellite System By Falin Wu Nobuaki Kubo Akio Yasuda Phu Son Nguyen ICS 280 1 31 2006 Current GPS Provides limited availability and capability Japan Mountainous terrain Urban canyons Japan Leads the world in the various applications of GPS equipment and services Civil use 5 7 million GPS equipped cellular phones 2 million GPS equipped car navigation units Annually sold Proposed QZSS Japanese Quasi Zenith Satellite System QZSS Augments GPS Highly elliptic orbit HEO satellites orbiting GEO synchronous Zenith direction high elevation angle Receive signal from at least one of the satellites Satellite Constellation 5 types of satellite constellations Considered with QZSS 3 favored types Discussed QZSS Options User located in Tokyo Track at least 1 QZSS satellite with 70 degree mask elevation 2 QZSS satellites with a 30 degree mask elevation Signal Structure QZSS uses Same signal structure as GPS and Wide Area Augmentation System WAAS Pseudorandom noise PRN code DOP Dilution of precision Measure for geometrical strength Lower the DOP is higher the quality of the position estimate GDOP is applied to evaluate the performance of positioning with code Ambiguity Success Rate Obtained once all these are known Functional model Stochastic model Integer ambiguity estimator Used to elevate the capability of carrierphase based positioning Higher Better the performance Software Simulations Spatial Variations Spatial Variations Spatial Variations Spatial Variations Spatial Variations Improve the satellite visibility Extend the positioning available area Offer better GDOP Improve the capability of carrier phase positioning Japan and neighboring regions 1st option More favorable availability accuracy and capability of carrier phase based positioning Temporal Variations Temporal Variations Temporal Variations Temporal Variations Temporal Variations Improve the satellite visibility Extend the positioning available area Offer better GDOP Improve the capability of carrier phase positioning Japan 1st option More favorable accuracy and capability of carrier phase based positioning Conclusion Improve the satellite visibility Extend the positioning available area Offer better GDOP Enhance the capability of carrier phase positioning 1st QZSS option Best for Japan 3rd QZSS option Best for the whole Asian Pacific and Australia area