NGS OPUS Won’t Process my GPS Observation File!


I collected static data with my (xyz) GPS receiver, just like I always do. It was in a wide open area, but when I submit data it reports that it cannot process the file or the vectors because they are noisy or fewer than 3 useable stations remain.


There are a lot of possible answers, but in this case the error message may be correct: “There are no nearby CORS stations WITH data.”

Let’s look at an example. [ Continue Reading …  OPUSWontProcess_R001 ]

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Checking the OS Version on a Surveyor 2

How do you check for the current OS Version on a Carlson Surveyor 2 (or Mini-2)?

[ OSVersionOnSurveyor2_R001 ]


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Example Metadata for GPS Job

Wow, there has been a lot of ink spilt on North Arrows and projection declarations for jobs based on GPS data.

Since I am not a licensed surveyor, my opinion does not count. But I get asked all the time. So here is an example of what I might do as a minimum:

I, Joe Blow, do hereby certify that I am a Professional Land Surveyor, holding 
certificate 99999 as prescribed by the State of Chaos.
I further certify that I have prepared the diagram represented herein and that
the same is an accurate representation of a survey, and was conducted under
my direct supervision.

  The Benchmark for this project is CP201

Coordinate System and Projection Information
  Horizontal Datum = NAD83, North American Datum 1983,
                     2011 Realization 2010.0 Epoch
  GPS Control = Maine DOT Virtual Reference System (VRS)
  Vertical Datum = NAD88, North American Vertical Datum of 1988, 
                   GPS Derived
  GEOID (used for GPS Derived Heights) = GEOID12B (NGS)
  Ellipsoid = GRS1980
  Projection = Maine West NAD83 State Plane Coordinates 
  Distance = US Survey Feet (1 Meter = 3937/1200 US Survey Feet)

  Distances are Grid distances converted to Ground using a Combined Scale Factor
  The Combined Scale Factor (0.99996067) for this project was derived at
    Control Point 201
          CP201 = 44 2 55.34000 N 69 58 23.05000 W NAD83
          Ellipsoid Height 215.562 ft
          GEOID            -57.100 ft
          Ortho Height     272.662 ft [NAVD88 (Computed using GEOID12B)]

    Example: 9,857.824 SFeet Grid = 9,858.206 SFeet Ground

    Bearings are with respect to State Plane Grid North
    Declination at
       TN-SP  0°  8’  4.57”
       TN-MN 15° 36’ 37” (2017 Estimate)


{My Seal}
Joe Blow
Chaos PLS Number 99999

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Reusing Jobs in One Projection in a New Job with a Different Projection

Let’s assume that we have an .RW5 (Raw File) for a job in one projection (a custom projection) and we want to reuse ‘SOME’ of the coordinates and GPS shots in this job, in a completely NEW job with an alternate projection.

Thesis: I have hundreds of control points and boundary shots for a job that were taken in a custom LDP. Now I want to work on an adjoining site, but in a new projection (or perhaps a standard State Plane Projection.)

If we assign the previous file as the control file of new job with a completely different projection, then we can import the RAW GPS positions to set a base, and we can use the raw data as the GPS coordinates for a localization.

Continue Reading > survce_reusingcoordintesbetweendifferentjobswithdifferentprojections_reva

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Connecting a SP80 Receiver to a NTRIP/DIP Mount Point with Wi-Fi and SurvCE / FAST Survey

The SP80 is billed as ‘the most connected receiver’ and without question, it is.

The internal Wi-Fi transmitter makes it possible to connect a SP80 directly to a Mi-Fi, which reduces the amount of data on the Bluetooth channel.

Let’s look at a comparison between the traditional ‘Data Collector Internet’ (DCI) configuration vs. the SP80 method  [ … sp80-survce_wifi_connection … ]

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Setting the HI in SurvCE for a Focus35 Robot

There are two measure-up indices on a Spectra Precision Focus-30 / Focus-35 Robotic Total Station:


The lower tape hook is for ‘Slant Height’. The top dot & cross is for ‘Vertical Height’.

If you enter a ‘Slant Height’, the data collector shows you the equivalent ‘Vertical Height’:


(Sorry, the picture is faded…to the right of ‘Vertical’ there is a 5.1600) If I measure 4.650′ to the tape hook then SurvCE computes 5.160′ to optical center.

Alternatively I could select the ‘Vertical’ radio option and then enter 5.16 directly.

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Setting Up a Base with Local Coordinates

[ See Also ]

“Okay, I understand that I MUST set my base to a geodetic location that is within 200 meters of my base’s TRUE geodetic location X, Y and Z. But I still want to set the base at a known position and I don’t have a transformation. I swear I can do this in other software packages!”

You can do it in SurvCE also. Here is how.

First go to “Equip: 6 Localization: GPS (tab)”. Set the One Point Azimuth to ‘Geodetic’ or ‘State Plane Grid’ as desired. If you are going to use a system like 1000,1000,0 then you probably want to pick ‘Geodetic’. If you are going to use a state plane or modified state plane coordinate then you undoubtedly want to select ‘State Plane Grid’:


Also check to make sure that an appropriate Geoid File is specified. Even if you are in Latin America and have a crappy Geoid file, you STILL need to select it or your elevation error will increase as you move away from the base.

Click on the green check mark to return to the Equip tab.

Do the standard base configuration steps: “Equip: GPS Base: setup Current, COMS, Receiver and RTK tab normally”. Click the Green Checkmark in the upper right corner.

The ‘Base Configuration’ tab is shown. Select the “From Known Position” tab:


In my case I want to enter local coordinates 1000, 1000, 0; so I click on the center button ‘Use Local Coordinates’:


Enter your desired coordinates, then click on the green check mark. SurvCE will ask you what you want to use for the localization file. The default is the job name with a .LOC extension:


Accept or modify the filename, then click on the green check mark.

SurvCE will read an autonomous position from the base. (In the USA this position will be within a couple feet of the IGS08 current epoch true position; elsewhere it will be within 5 meters.)


Click on ‘Yes’ to continue.

The base will be configured and SurvCE will ask if you want to store a reference file:


Click on ‘Yes’


Choose an appropriate name and click on the green check mark.

Your base is now broadcasting corrections and if you could occupy the Base Point (under the base) with your rover, the rover would read ‘1000.00, 1000.00, 0.00’ as you desired.

You are ready to survey, but let’s spend a few extra minutes and address two things:

  • what is going on in the background?
  • how do I setup on this same base point the following day?
  • what if I have more than one rover?

What is Happening in the Background?

First off, SurvCE has done a ‘Read GPS’ and used the autonomous location to initialize the base. The base does not think that it is at 1000, 1000, 0; the base thinks it is at a position that is very close to it’s TRUE position:


SurvCE automatically sets up a single point localization. You can view it by going to “Equip: Localization: Points”:


Notice that the control point’s local coordinates are the point  that I manually entered. Click on the ‘View’ button:


and the corresponding geodetic position is the autonomous (WAAS corrected) base point. This base point is also saved in the .REF file.

So to recap, SurvCE has initialized the base with a ‘Read GPS’ position and then automatically configured a single point localization that results in the base reading the exact local coordinates that I requested.

How do I setup on the Same Base Point on a Following Day?

You want to use the .REF file to insure that the base is initialized with the exact same geodetic position that was used on the first day.

Setup the base over the EXACT same X-Y location as the first day. The HI does not need to match. Enter the correct HI on the ‘Receiver’ tab:


When you click on the green check mark, you will go to ‘Base Configuration’ dialog. Select the ‘From Known Position’ tab:


Click on the ‘Read From File’ button at the bottom:


Select the same reference file that you saved on the first day, then click the green check mark.

SurvCE will check to insure that the broadcast geodetic location is close to the actual location, then display the position read from the file:


Click on Yes:


And the base is reconfigured exactly as it was the first day. Since you are still using the original job file, the correct localization is automatically used. You are good to survey!

What if I have Multiple Rovers on my Job?

Then you must move the localization file (.LOC) onto each of the other rovers and load it with the load button in ‘Equip: Localization: Points (tab)’:


Then select the .LOC which you moved from the first rover data collector:


Again, the second rover is now ‘registered’ with the same localization and will follow the first rover’s coordinates exactly.


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