Opus X Your Software

[Vickiana Sconyers]

PROBLEMOPUS doesn39t recognize the internal format of your data file reac1234.00o as RINEX, or as any format it could translate to RINEX.WHAT TO DO: translate your data file to RINEX yourself before uploading. Ask your receiver manufacturer for format conversion software, usually available for free.

9999 Error: Datasets less than two hours in duration no longer accepted to OPUS-S.

9999

9999 Your data file appears to span less than 2 hours. OPUS guidelines require a

9999 minimum data span of 2 hours and strongly recommend 4 hours to achieve

9999 best accuracies. Datasets less than two hours in duration are no longer

9999 allowed in OPUS-S. Please re-submit your data to OPUS-RS.

9999 If your file is actually over 2 hours, check for formatting compliance

9999

Rest assured though that PAGES (the underlying OPUS software) can NOT process single frequency data. Yes there are single frequency antenna models which can be selected like say the NovAtel 501, but OPUS does REQUIRE dual frequency GPS data. Without it you will get a random error message.

9005ERROR! OPUS terminated in one of the processing modules.

9005 The dataset submitted to OPUS cannot be processed. The file

9005 contains data that is very noisy and probably has many data gaps.

9005

The file I submitted to CSRS came back in about 10 minutes with a full report and was able to resolve the location within +/- .009 and .006 m (Latitude and Longitude) and +/- 3.23 cm on elevation although I believe that is because I was unable to figure out how to set the antenna calibration.

Anyone else have this issue? Check out the satellite plot from RTKLib. I have sent this issue in to Emlid but have not heard back yet so I figured I would post this here in case someone in case anyone has seen this very same issue.

According to OPUS support, approximately 90% of solutions use 70% or more of the observations, and approximately 30% of solutions use 90% or more of the observations. They also say that the longer the session duration is, the better the results tend to be.

I converted your data to Rinex 2.11 and ran it through WinTeqc to check the data. It reported an error with R26 and invalid data on G23. I then excluded those two satellites when converting to Rinex again. This fixed the time duration issue but OPUS then reported the same 9011 error you had. I have sometimes found that if you wait for a few days, the same file will then process and give a solution. As an additional test I submitted the data to the CSRS-PPP site and it processed the data successfully and returned a position.

As mentioned by Jasonl there are some satellite data quality issues. This makes things more difficult for OPUS when you are working with minimum time period requirements AND you have a L2C-only receiver.

A service like the Canadian CSRS-PPP which also uses dual frequency Glonass might be the better choice if you need to limit the observation time. Of course, good old-fashion differential processing will get you the best accuracy in the shortest amount of time when there are CORS reasonably close like you have.

A literary opus is often a single novel, though the word may sometimes refer to all of a writer's works. But opus normally is used for musical works. Mendelssohn's Opus 90 is his Italian Symphony, for example, and Brahms's Op. 77 is his Violin Concerto. Since many composers' works were never given opus numbers in an orderly way, they now often have catalog numbers assigned by later scholars. So Haydn's Symphony No. 104 is Hob.104 (Hob. is short for Anthony van Hoboken, the cataloger), and Mozart's Marriage of Figaro is K.492 (K. stands for Ludwig Kchel).

NOAA's Online Positioning User Service (OPUS) provides free access to high-accuracy National Spatial Reference System (NSRS) coordinates. OPUS uses the same software which computes coordinates for the nation's geodetic control marks and the NOAA CORS Network (NCN).

To use OPUS, simply upload a GPS data file (collected with a survey-grade GPS receiver) to the OPUS upload page. Your computed NSRS position will be emailed to you. If you choose, your position can also be shared publicly on the NGS website, or added to a larger survey project.

Enter the vertical height (in meters) of your Antenna Reference Point (ARP) above the mark. See antenna calibration for a drawing of the ARP for your antenna (usually the center of the base or tripod mount).

Under normal conditions, most positions can be computed to within a few centimeters. However, estimating the accuracy for a specific solution is difficult because formal error propagation is notoriously optimistic for GPS reductions. User errors (such as misidentification of antenna or ARP height) cannot be detected. Local multipath or adverse atmospheric conditions may also negatively impact your solution.

Rapid-Static: The best estimates of coordinate errors are the standard deviations reported by single baseline analysis. Our experiments indicate that the actual error is less than these estimated accuracies more than 95 percent of the time.

Please note: OPUS-RS may perform poorly or fail during periods of high ionospheric disturbance or during the passage of a strong weather front. In general, it is best to avoid collecting GPS data during these events. To avoid collecting data during a geomagnetic storm, see NOAA's Space Weather Prediction Center, which issues geomagnetic storm alerts.

For static: overall root mean square (RMS) error for the doubly-differenced iono-free carrier phase observables for the three single baseline solutions.

For rapid static: a unitless normalized RMS

Your position: Earth-centered cartesian coordinates in the International Terrestrial Reference Frame (ITRF).

The North American Datum of 1983 (NAD83) is also reported, if applicable.

Accuracies below are reported as either solution range errors (static) or standard deviation estimates (rapid static).

All initial computations are performed in ITRF. Your NAD83 coordinates are derived by transforming ITRF vectors into the NAD83 reference frame and recomputing the 3 independent and averaged positions (not a direct transformation of the ITRF coordinates; a direct transformation could be considered more accurate, but wouldn't fit your surrounding NAD83 network as well.) For both ITRF and NAD83, the reference coordinates for each CORS are derived from the NGSIDB and are updated using crustal motion velocities from HTDP (Horizontal Time-Dependent Positioning software to your data file's epoch. Your final ITRF reference frame coordinates retain this observed epoch, while your NAD83 coordinates are transformed again to the standard epoch date of January 1, 2010.

I got a warning message that the IGS Precise Orbit was not available at the time of processing, but the "rapid" was used. What does that mean? We will not have the "final" IGS Precise orbit until the International GPS Service (IGS) completes a full week (Sunday through Saturday). This final precise orbit is the combination of seven analysis centers worldwide. It can take these analysis centers several days to upload the orbit to the IGS so the availabilty of a Sunday orbit can be 19 days. The IGS rapid orbit is used in the absence of the IGS precise orbit. However, this is not cause for alarm since the IGS rapid is nearly as "good" as the IGS precise. How does this relate to positions on the ground?

Since most OPUS baselines are less than several hundred kilometers, the differences between using the IGR (rapid orbit) and the IGS (precise orbit) is barely detectable if at all. Because of this, OPUS has discontinued this warning message (1/1/2004). For more information see IGS.

Some of my attempts to submit data generates a return email saying, "The observations to slip ratio is too low. There were an unusually high number of cycle slips in the data set. Aborting ..." (Code 1012). What does this mean, and how can I correct it? This error message primarily indicates that your carrier phase data set contains too many cycle slips to assure an automated hands-off processing to obtain accurate results. The data may still be useful, but will require human intervention to efficiently resolve the cycle slips. Perhaps nearby radio interference or obstructions have caused an unusual amount of cycle slips.

I am trying to upload a RINEX file and I am getting a message that there are illegal characters in the file name -- what am I doing wrong? The problem is probably not with the file name, but with the path name. OPUS is run on a UNIX machine, and it can only read path names that contain numbers, letters, the period, dash, and the underscore. If you move your file to another directory, it should be able to be uploaded.

FAQs - Static I uploaded data. Why no response? Solutions are usually sent within a few minutes, but it may take more than an hour to complete if traffic is heavy or your file is large. You will eventually receive either a solution or a failure message. Take care to enter your email address correctly and check your spam filters.

My nearest CORS weren't used. Why not? OPUS tries to use your nearest CORS, but tests the integrity of each dataset, and will expand the search area until enough quality data are found. Also note some CORS data are not available until the following day. You may use OPUS options to force include or exclude specific CORS.

Is antenna required? If I select "NONE" will it use the L1 phase center? While strongly recommended, if you leave the antenna as NONE your data will be processed with no offsets applied, resulting in a position a few centimeters above or below the L1 phase center. Ignoring your antenna's phase center variations will be interpreted as changes in tropo delays, causing errors in the tropo parameters which will degrade your solution.

What is the ARP height for Leica antenna model SR 399, with GRT44 tripod mount? If you have this type of antenna mounting, the ARP height can be determined by using the following equation: Height of ARP (meters) = 0.350 + tape measurement (meters) "Tape Measurement" is the distance in meters from the bottom of the hook in the antenna mounting to the monument.

Why do so many antennas include the term "NONE"? What are SPKE, SNOW, SCIS, etc? A NONE suffix means no radome, a shell occasionally used to protect permanent antenna installations. OPUS identifies antenna types using the 20-character antenna+radome codes adopted by the International GNSS Service (IGS); see antenna calibration for more information.

My NAD83 coordinates are missing. Why? Sometimes OPUS uses CORS from outside the NGS CORS network that only have IGS reference frame positions and no listed NAD83 positions. Your resulting positions will be just as good as if all CORS were used, except the NAD83 positions will not be listed. You may wish to go to the NGS home page, click on "Products and Services", and download the program HTDP. This program converts positions between different reference frames.

How do the NAVD88 heights from GEOID18 compare with heights from GEOID12B, GEOID09, GEOID03, or GEOID99? Newer geoid models provide improved orthometric height accuracy. Upgrade your older GPS heights as follows: NAVD88new geoid = NAVD88old geoid - new geoid ht + old geoid ht. Use the interactive computations tools within geoids or VDatum to compute geoid heights for your project area.

contact OPUS

Sharing your OPUS solution

Why share?Your data helps maintain local ties to the National Spatial Reference System (NSRS). Your shared solutions will also help your community prepare for the NSRS modernization in 2022 by contributing to the GPS on Bench Marks for the Transformation Tool campaign (GPS on BM). The Transformation Tool will enable conversions from current vertical datums to the new North American-Pacific Geopotential Datum of 2022 (NAPGD2022). To see examples, check out shared solutions near you.

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