WAAS Clarification

March 27, 2006  - By


The FAA’s announcement (reported in March GPS World) that WAAS in the northeastern United States and eastern Canada may be significantly inhibited by relocation of WAAS-broadcasting satellite AOR-W before the new PanAmSat becomes fully operational in fall 2006 caused unease in some surveying organizations. Based on tests completed last year, before anyone knew that AOR-W would relocate to 142W longitude, these organizations replaced legacy GPS mapping units using post-processing and the Coast Guard NDGPS with high-performance WAAS-enabled mapping receivers.

The FAA notice doesn’t tell the full story, however. Two new WAAS broadcasting satellites launched last fall. PanAmSat (133W) began broadcasting in test mode with corrections full-time this March, and Telesat (107W) is scheduled to begin the same mode on or around April 1, 2006. The FAA announcement does not take into account either of these broadcasting satellites.

If these test signals are considered, there will be no degradation in WAAS visibility. In fact, users in the northeastern United States and eastern Canada will enjoy dual WAAS satellite coverage. WAAS satellite visibility in central and western North America has improved in the past 60 days with the new test signals and relocation of AOR-W.

However, the FAA won’t certify the accuracy/reliability of the new satellites until after extensive testing. Until then, non-aviation receivers may use the signals at their discretion &#151the same mode WAAS operated in prior to its July 2003 commissioning. Also, non-aviation WAAS receivers may not be configured to use the new test signals; check with the manufacturer.

&#151 Eric Gakstatter, Editor of GPS World’s new Survey &#38 Construction E-Newsletter

This article is tagged with , and posted in Opinions, Survey

About the Author:

Eric Gakstatter has been involved in the GPS/GNSS industry for more than 20 years. For 10 years, he held several product management positions in the GPS/GNSS industry, managing the development of several medium- and high-precision GNSS products along with associated data-collection and post-processing software. Since 2000, he's been a power user of GPS/GNSS technology as well as consulted with capital management companies; federal, state and local government agencies; and private companies on the application and/or development of GPS technology. Since 2006, he's been a contributor to GPS World magazine, serving as editor of the monthly Survey Scene newsletter until 2015, and as editor of Geospatial Solutions monthly newsletter for GPS World's sister site Geospatial Solutions, which focuses on GIS and geospatial technologies.

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