PEDESTRIAN AND VEHICULAR NAVIGATION UNDER SIGNAL MASKING USING INTEGRATED HSGPS AND SELF CONTAINED SENSOR TECHNOLOGIES

The performance enhancements achievable under signal masking such as urban canyons, indoor and under the forestry canopy with High Sensivity GPS (HSGPS) technology are first described using sample field results. HSGPS uses a longer integration time in order to utilize signals that are 25-30 dB weaker than the nominal line-of-sight GPS signals. A self-aided implementation of HSGPS that does not require external aiding from an existing network was tested. Depending on the type of signal masking, availability increases substantially. However, this occurs at the cost of increased susceptibility to interference which leads to very large measurement errors in some cases. Many tests obtained under a variety of conditions and summarized in the paper demontrate this clearly. In order to improve HSGPS overall performance (availability, accuracy, and reliability), integration with self-contained portable, preferably low cost sensors, is described. These sensors include miniature accelerometers, gyros, and six degrees of freedom IMUs. A performance analysis of vehicular and pedestrian applications of HSGPS conducted under a variety of conditions shows the advantages and limitations of self-contained sensor augmented HSGPS.