Andrew Hansen
Stanford University
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Publication
Featured researches published by Andrew Hansen.
ieee/ion position, location and navigation symposium | 1998
Eric Peterson; Todd Walter; Andrew Hansen; Per Enge
The Wide Area Augmentation System (WAAS) is designed to augment the Global Positioning System (GPS). One of the services provided by WAAS is a broadcast ionospheric correction based upon dual-frequency measurements. These observations are used to construct a grid of expected vertical ionospheric delays. To date, the broadcast single frequency model has been used to project vertical delay observations onto the predefined grid points. The performance of the WAAS ionospheric grid could be improved by incorporating a more realistic description of the ionosphere than this nominal transport model. In this paper we explore the use of IRI90 for this purpose by means of a software-based WAAS simulator. The quality of the broadcast WAAS ionospheric corrections is tested by comparing the ionospheric delays predicted by the WAAS grid algorithm with those derived from a truth source. Results to date indicate that using a transport model derived from IRI90 yields a small improvement over the broadcast model.
Annual of Navigation | 2001
Todd Walter; Andrew Hansen; Juan Blanch; Per Enge; Tony Mannucci; Xiaoqing Pi; Larry Sparks; Byron A. Iijima; Bakry El-Arini; Roland Lejeune; Mine Hagen; Eric Altshuler; Rob Fries; Aleck Chu
Proceedings of the 10th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1997) | 1997
Andrew Hansen; Todd Walter; Per Enge
Proceedings of the 11th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1998) | 1998
Sam Pullen; Guttorm Opshaug; Andrew Hansen; Todd Walter; Per Enge; Bradford W. Parkinson
Proceedings of the 2001 National Technical Meeting of The Institute of Navigation | 2001
Todd Walter; Andrew Hansen; Per Enge
Proceedings of the 10th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1997) | 1997
Todd Walter; Per Enge; Andrew Hansen
Archive | 2001
Larry Sparks; A. J. Mannucci; Todd Walter; Andrew Hansen; Juan Blanch; Per Enge; Eric Altshuler; Rob Fries
Proceedings of the 1999 National Technical Meeting of The Institute of Navigation | 1999
Jock Christie; Ping-Ya Ko; Andrew Hansen; Donghai Dai; Sam Pullen; Boris Pervan; Bradford W. Parkinson
Proceedings of the 2000 National Technical Meeting of The Institute of Navigation | 2000
Andrew Hansen; Eric Peterson; Todd Walter; Per Enge
Annual of Navigation | 2000
Jonathan Nichols; Andrew Hansen; Todd Walter; Per Enge
