Precise Platform Positioning with a Single GPS Receiver

摘要

With the removal of Selective Availability about two years ago, the twice-distance root-mean-square horizontal accuracy of single-receiver, single-epoch GPS point positioning afforded by the Standard Positioning Service has improved to better than 10 meters in many situations. Differential positioning techniques and the use of carrier-phase data can provide higher accuracies, even to sub-centimeter levels. However, these techniques require raw data or corrections from another receiver. The subject of this month's column is the design of a GPS data processing technique capable of producing positions with accuracies at the few-decimeter level using data from a single receiver, regardless of platform dynamics. This feat is accomplished by combining two processing philosophies: point positioning - making use of precise GPS constellation ephemeris and clock offset information to estimate a single receiver's state; and carrier-phase-filtered, pseudorange processing - supplementing pseudorange-based positioning with carrier-based position-change information.