Evaluation of the Online Positioning User Service for Processing Static GPS Surveys: OPUS-Projects, OPUS-S, OPUS-Net, and OPUS-RS
Publication: Journal of Surveying Engineering
Volume 145, Issue 3
Abstract
The National Geodetic Survey has developed four versions of the online positioning user service (OPUS) for postprocessing dual-frequency, static global positioning system (GPS) data. Each version was designed for a different application and outputs coordinates at a mark to varying accuracy. To compare the accuracy of these four versions, 88 10-h-duration GPS data files collected on 18 marks in Oregon were processed in OPUS-Projects, producing horizontal coordinates and ellipsoid heights at these marks with an estimated network accuracy of less than 0.5 and 1.3 cm at 95% confidence, respectively. Then, these data files were windowed into sessions ranging from 20 min to 10 h in duration. The windowed files were processed in OPUS-static (OPUS-S), OPUS-Net, and OPUS-rapid static (OPUS-RS), and the resulting coordinates at each mark were compared with the coordinates from OPUS-Projects. At a session duration of 2 h, OPUS-RS was found to be more accurate than both OPUS-S and OPUS-Net. For sessions less than 2 h, OPUS-RS frequently produced poor solutions with error messages. At a session duration of 4 h, OPUS-S and OPUS-Net produced coordinates with both horizontal and ellipsoid height errors less than 3 cm at 95% confidence.
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Acknowledgments
National Oceanic and Atmospheric Administration (NOAA) funded part of this research study by cooperative agreement via the Cooperative Institute for Marine Resources Studies (CIMRS), award No. NA11OAR4320091. Leica, David, Evans and Associates and the Oregon Department of Transportation provided most of the survey hardware for the survey campaign in Oregon. Mark Armstrong, National Geodetic Survey (NGS) regional adviser (retired), provided helpful guidance when processing the data in OPUS-Projects. Oregon State University civil engineering students Michael Eddy, Marian Jamieson, Nathan Jones, and Tyler Wall assisted with the survey and/or helped organize and process the raw GNSS data. Weibing Wang, NGS geodesist, assisted with loading the RINEX files to OPUS-RS and OPUS-Net.
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Published In
Journal of Surveying Engineering
Volume 145 • Issue 3 • August 2019
Copyright
© 2019 American Society of Civil Engineers.
History
Received: Oct 8, 2017
Accepted: Dec 10, 2018
Published online: Jun 6, 2019
Published in print: Aug 1, 2019
Discussion open until: Nov 6, 2019
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