Precise Positioning with Local Signal Carrier Phase Measurements, Global Positioning System (GPS) and Inertial Data Fusion

QuNav and Illinois Institute of Technology propose the development of local-radio carrier phase methodology mechanization. Phase I will develop carrier phase tracking approach; and, precise positioning mechanization. Carrier phase of CDMA signals (such as pseudolites) will be tracked by utilizing the GPS receiver design to minimize changes for legacy receivers. For TDMA radios (such as Link 16), our innovative tracking approach will maximize the use of existing communication receivers (an inner loop for symbol decoding) and will add two additional layers (a mid-loop for tracking over the dedicated time slot and a feed-forward loop for coasting over idle periods) to enable the tracking of carrier phase. The proposed methodology of precise positioning is based on a carrier phase-only estimation approach. Highly accurate positioning is enabled by observing local-radio transmitters from multiple locations over time (thus synthesizing a favorable measurement geometry) and applying displacement information (derived from temporal phase changes) to combine these multiple observations. The proposed development starts from local-radio positioning mechanization, then augments it with inertial navigation, and finally adds GPS measurements. It is expected that the use of local radio carrier phase will enable automated landing scenarios such as Case-I shipboard landing, which is challenging to GPS alone.