Architectures for Joint GPS/LEO Satellite Carrier Phase Receivers Designed for Rapid Robust Resolution of Carrier Cycle Ambiguities on Mobile Platforms

摘要

The emerging satellite telecommunication industry hasrnseen substantial progress in the design and manufacturernof low-cost, low-power transceivers which interface directlyrnwith Low Earth Orbit (LEO) Telecom Satellites.rnHerein, we describe the architecture of a joint GPSLEOrnnavigation receiver which tracks LEOS in conjunctionrnwith GPS in order to rapidly resolve cycle ambiguitiesrnon both the GPS and LEO signals. The objectivernis to achieve centimeter-level navigation performancernusing pre-existent LEO transceiver hardware, designedrnfor low-cost data communication. The obstacles tornbe overcome include: synchronization of the LEO andrnGPS receivers, precise time-tagging of carrier-phasernmeasurements without the use of hardware accumulatorsrnand latches, accommodating different frequencydependentrnphase lags for each of the receiver paths, andrnthe ability to scale the number of trackable LEO satellitesrnand/or antennas in firmware. Different techniquesrnfor performing the integrated phase measurement, consistentrnwith these objectives, are discussed. We describernthe radio-frequency hardware, together with anrnefficient information smoother which we apply to thernestimation of cycle ambiguities.