WAAS Implementation for the OSGPS Receiver

TitleWAAS Implementation for the OSGPS Receiver
Publication TypeThesis
Year of Publication2007
AuthorsHagerman, DP
AdvisorMakela, JJ
Academic DepartmentDepartment of Electrical and Computer Engineering
Number of Pages81
Date Published05/2007
UniversityUniversity of Illinois at Urbana-Champaign

Single-frequency Global Positioning System (GPS) receivers lack real-time integrity monitoring of malfunc- tioning satellites and are highly susceptible to transient total electron content (TEC) values produced by magnetic storms. These electron density fluctuations, combined with the ionospheric errors that remain uncorrected by the Klobuchar model, introduce large errors in the user position. In response to these issues, the Federal Aviation Administration (FAA) developed the Wide Area Augmentation System (WAAS) to provide corrections and integrity monitoring for the GPS. The WAAS corrections were used to augment a Linux-based OSGPS receiver. This implementation involved the acquisition of the WAAS data on the GPS- L1 frequency, testing the algorithms, modifying the driver, and writing application software to apply the corrections to the navigation solution. The WAAS corrections were verified and successfully applied to the OSGPS receiver, yet the position accuracy was not improved over GPS-only navigation. Even though the performance results were less than expected, the WAAS still augments the GPS with the essential integrity monitoring information necessary for safe aviation.