Notes

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Outline

1	OPUS: Online Positioning User Service
2	WHAT IS OPUS?
3	Areas Covered by OPUS
4	How Does OPUS Work?
5	OPUS Guidelines
6	How Does OPUS Compute Position?
7	Time-series plots, 60-day and long-term
8	How Does OPUS Pick Base Stations? Estimate position for remote station Compute distance to every available CORS Sort CORS by increasing distance Select the 5 closest CORS Look at 1^st 3 CORS with TEQC program. Criteria: ● data cover time span for remote station ● > 80% of data available ● low multipath ● if not, replace with 4^th CORS (then 5^th) 6. Start single baseline solutions using 1^st 3 CORS ● check solution quality ● if bad solution, replace CORS with 4^th (then 5^th)
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11	Using the OPUS Web Page
12	Allowable Data Formats Compressed archive of multiple files. Archive must contain RINEX “site123h.04o” or Hatanaka “site123h.04d”
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15	Reading OPUS Output
16	Reading OPUS Output con’t.
17	Guidelines for Good Solution
18	Reading OPUS Output con’t. Solution/Coordinates
19	How Does OPUS Compute Errors?
20	OPUS Output con’t. Grid Coordinates
21	READING OPUS OUTPUT (control)
22	How Can I Improve My Results?
23	Distribution of Horizontal Offset from Accepted Values
24	Distribution of Vertical Offset from Accepted Values
25	Error Messages and Warnings “The OPUS positioning software is only available for use for datasets taken/recorded in one of the areas determined to be valid for OPUS A solution will not be performed on the dataset submitted. The time span of the submitted dataset is too short. OPUS needs a minimum of one hours worth of data to begin processing. The dataset submitted to OPUS does not meet the RINEX standard. Please re-submit the data in RINEX 2.0 or 2.1 standard. Aborting... The dataset submitted to OPUS contained too many data gaps or a large number of sampling interval changes. Aborting... WARNING! No antenna type selected. An antenna pattern will not be applied. The observations to slip ratio is too low. There were an unusually high number of cycle slips in the dataset. Aborting... ERROR! Opus terminated abnormally in one of the processing modules.
26	How do I get help?
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30	CONTROLLING A BRIDGE SURVEY
31	Using OPUS to control Bridges On a typical bridge job, NCDOT Sets an azimuth pair ( ) Uses approximately 6-7 control panels ( ) Controls the site with 2 receivers
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34	Field Work is now complete. The following steps need to be taken to finish the process:
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39	HOW IS THE ANTENNA HEIGHT MEASURED?
40	WHY DO I NEED THE ANTENNA TYPE?
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45	Recent Solutions
46	Files processed during even-numbered months, 2002-2005
47	OPUS usage for one month
48	Total OPUS usage during 2005
49	ONGOING CORS RESEARCH * Exploring the use of NTRIP to stream GPS data from selected CORS via the Internet. * Developing OPUS-GIS which will process a few minutes of GPS code range data (for sub-meter accuracy) * Developing OPUS-RS (rapid static) that will enable users to obtain positional coordinates with cm-level accuracy using only 15 minutes of GPS carrier phase data
50	“OPUS Projects”—under long-term development OPUS files identified as belonging to a project are directed to appropriate directories Project data submission organized Reports sent to project managers Station data checked and edited as needed PAGES GPS processing accomplished ADJUST run