Pseudorange Observations Research Articles

NAVSTAR/GPS Single Point Positioning at Sheltech Canada — Preliminary Results

Sheltech Canada’s active involvement in the use of Navstar/GPS for positioning was highlighted by the acquisition, in mid 1980, of a second generation geodetic receiver from Stanford Telecommunications Inc. of Sunnyvale, California, U.S.A. A brief description of Sheltech’s STI 5010 GPS receiver, auxiliary equipment and real-time software required to operate the system is presented. Mathematical models and least-squares algorithms used to derive three-dimensional positions from pseudorange observations are described. Related validation tests carried out over several months indicate that the anticipated 10-m accuracy (1 σ level) for instantaneous single point positioning, predicted for the fully operational GPS constellation starting in 1987, is already achievable for certain periods of time. Sheltech’s future plans regarding offshore and land positioning, and the integration of the GPS receiver system with other navigation aids, e.g., inertial systems, are summarized.