Papers - Capabilities of Currently Available GPS Receivers for Precise Autonomous Positioning

Roger Shreenan, Luc Villeneuve and Robert Duval
Geodetic Survey Division

Abstract

What accuracies are achievable with different GPS receivers? This is the question most often asked by users of the Canadian Active Control System (CACS) performing GPS point positioning using precise ephemerides and clocks. Users of these CACS products obtain DGPS-like accuracies anywhere in Canada, without access to base station data. This is accomplished by post processing their receiver observations and replacing broadcast satellite orbits and clock parameters with precise orbit and clock information. This approach provides single epoch positioning accuracy at the sub-metre level to users operating receivers with low measurement noise and antennas with good multipath rejection performance.

To assess the positioning accuracy of various GPS receivers (offering raw data in the RINEX format), tests were conducted in static and kinematic mode using this autonomous positioning approach. In static mode, averaging periods of varying length were compared to help determine the optimum occupation period needed to reduce the effect of some of the random errors in the observations. The results provide an indication of the accuracy that can be expected from various receiver types when using CACS for precise point positioning.

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