Global positioning system based method for high-accuracy and high-confidence level absolute and relative position and velocity determinations

摘要

An embodiment of the present invention is a shipboard GPS positioning system (12) having data links (28, 30, 32, 34) to outlying tailbuoys (18, 20, 22, 24) requipped with respective GPS receivers. On ship (12), an Intel 386-based microcomputer system collects data from various ship's equipment including the ship's GPS receiver and data from the several tailbuoy units (18, 20, 22, 24). A computer-implemented process located in the microcomputer system controls the following processes. Periodically each GPS receiver produces updated pseudo ranges (PRs) and these are time-tagged. The time-tagged PRs for the ship (12) are aligned according to their time tags with their counterpart PRs from the tailbuoys (18, 20, 22, 24). The raw PRs are then passed through a Kalman mathematical filter to produce filtered pseudo ranges$\mathop{\mathrm{image}}$;A position solution is then attempted for each GPS receiver using the; $\mathop{\mathrm{image}}$The filters provide statistical data that is used to rate the quality of each; $\mathop{\mathrm{image}}$in a weighted least squares solution process. Special measures are included to provide quality control/quality assurance, including the user of error ellipses on the display to present a graphic indication of expected solution accuracy, and the use of real time fault detection, isolation, and correction algorithms when redundant satellite information is available.