WADGPS PROCESSING LATENCY REDUCTION | ||
| International Conference on Aerospace Sciences and Aviation Technology | ||
| Article 88, Volume 10, 10th International Conference On Aerospace Sciences & Aviation Technology, May 2003, Pages 767-775 PDF (1.29 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/asat.2001.59687 | ||
| Authors | ||
| M. A. Matar1; S. Y. Issa2 | ||
| 1Avionics Depart., MTC. | ||
| 2Syrian Assad Academy. | ||
| Abstract | ||
| Global Positioning System (GPS), the most advanced navigation system, suffers three problems that are very pronounced for safety critical applications like Aviation. These problems are namely: accuracy, availability and integrity. Standalone solutions to these problems have been developed and conceptually integrated in a framework known as Satellite Based Augmentation System (SBAS) in the 1990s. This work deals with the GPS positioning accuracy improvement obtainable out of SBAS through reduction of orbit and clock errors. More specifically, implementation of Wide Area Master Station (WMS) covering estimation techniques for these errors is extensively studied on the bases of Kinematic, and Nondynamic approaches. Published approaches rely on solving the problem of orbit error estimation on the bases of transmitted pseudorange errors yielding WMS processing latency of about 7 minutes using P-III 500 MHz IBM PC and a MATLAB 5.3 environment. This processing latency is intolerable and falls very far from the FAA time-to-alarm requirement (about 8 sec for en-route through non-precision approach phases and 5.2 sec for precision approach). To reduce the processing time to the level required by the FAA time-to-alarm, this work proposes to solve an equivalent problem of orbit determination rather than orbit error determination. Research for accelerating and improving the performance of Nondynamic approach has resulted in reducing processing time to about one fiftieth of the corresponding time obtained by implementing published solutions. | ||
| Keywords | ||
| Global Positioning System (GPS); Satellite Based Augmentation Systems (SBAS); Wide area differential GPS (WADGPS); satellite ephemeris; Orbit; pseudorange; Least squares; processing latency; Wide Area Augmentation Systems (WAAS); Wide Area Master Station (WMS); Wide Area Reference Station (WRS) | ||
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