RTK Adjustment (Leica Geo Office)

You Cannot Hold Them All

You begin the day at a control point and end at a control point. You adjust after you are done so you can evaluate all your control checks.

Without continuity to your data jumping around to various control points is a crap shoot.

Paul in PA

> When running RTK (Network or Base/Rover Setup)while collecting data I always check into several vertical benchmarks and horizontal control points. Back in the office, using Leica Geo Office, I adjust all data by adjusting my base by my miss to the control points (When within tolerance). This shifts all points and will make my control points match the published values.
If you have the LGO adjustment module you can hold the tied control points and float the base station position. Perhaps this is what you are doing. But that's in the office, not the field .

>When checking into a control points at the start in the field, is there a way to tell the collector to make it hold the published value? I use the Leica GS14 with a Leica CS15 collector.
You could set up a transformation - ie/ a site calibration. I'm not familiar enough wirh Lieca's field software to guide you on just how this is done, but all, or almost all, dc software will do something like this.

But remember that a certain amount of "error" is normal, and a remeasurement of the same control point a few minutes later will differ from the first. You could be just chasing your tail if you are constantly trying to match control points you tie throughout the day.

You should be able to do this in the field. What you are describing is a typical localisation or calibration where the base is not set on a known point. This is the same senario as using a RTN where the CORS is on a different datum or epoch. We use R8's controlled by TDS so I can't help you with specifics. We used to use SR530's in the same manner.

Hunter,

It sounds like your local control is on a different epoch than the NRTK network. While you can adjust the data in the office holding your local control, you can not tell the C15 to hold your value for the base. You need to perform a transformation in either LGO or on the CS15. In LGO this is done under the 'Datum and Map' tool and on the CS15 in 'Determine Coordinate System' program (at least that's what it is called in SmartWorks). This will create a project specific coordinate system that matches your local control. In both systems you will need to determine the best transformation method for your situation. Leica being Leica does not have a simple scale, shift, tilt, rotate transformation.

I would strongly suggest that you make sure you have good observations on the local control. Any error in the measurements will be amplified throughout the project.

Hunter,

In the Leica Geo Office, (LGO), when you import the RTK Data, The RTK Base, or Reference Station will have a "Reference" Point Class. There are about nine types of point clasess in LGO, Control, Reference, Measured, Averaged, Navigated, etc.

Select the RTK Base Point, the default Point Class = Reference.
Select the RTK Base, right-mouse click - Properties, reveals WGS84 Latitude, Longitude and Ellipsoid Height values. The user can edit this position, Update and Save, Any/All RTK side-shots point values will be be re-computed based upon the Edited RTK Base position, new coordinates for the RTK data points are computed.

If the RTK Base point Class is set to any other than "Reference", the RTK side shot point positions are NOT updated.

In LGO the same applies to the Total Station, Robotic TS Data. The default Point Class is "Reference".
In LGO, GNSS Baselines + RTK Vectors are displayed in RED,
Total Station/Robotic TS measurements are displayed in Green.
Digital Level data is displayed in Purple.

In the field, The RTK Base can obtain a "Measured Position" Using the radio or cell modem, Broadcast or TX the Measured WGS84 Lat-Long-Ellip Ht to the RTK Rover, and collect/log simultaneous Static data into the GNSS receiver;s memory. Post-mission, you can down load the Static data file, convert into Rinex observation file >> Upload to NGS OPUS Service. When you receive the NGS OPUS Solution Report, you can return to LGO, open the RTK Project, in the Map View, edit the RTK Base position's Reference Class point value, bump the Lat-Long-Ellip Ht over the NGS OPUS Solution value, recompute the RTK Side shots.

Using our Hemisphere GNSS RTK Base + RTK Rover, (S320 GNSS receiver) and the Carlson SurvCE and our GeoSurveyor Office Post-Processing SW, you can same the same exact thing.

-BbBB-)

Hunter,

I think everyone covered the answer pretty thoroughly. The creation of a local transformation and review of the residuals would be the best way to go as described in other posts.

One other procedure to consider with this situation would be to get as many multiple observations as possible on each "control point" as possible. I know this is not always logistically possible due to time and money in the job but try to observe an RTK positions on each point say once in the morning once at noon and once in the evening. That way you are averaging the results with different solutions for the RTK observations. Just call the point the same exact name in the same job and take an RTK position on it again. The database in SmartWorx keeps each independent observation but also produces and averaged coordinate which considers all of the observations unless you edit the averaged coordinate and tell the software not to use certain observations. You set you averaging limits in the properties of the job when you create it under the Averaging page. If you measure and observation on a point that will be averaged and it is outside of this averagiung limit the system will warn you before you choose to or not too store the values. Again, I know this is a logistical problem to travel to points multiple times but the redundancy of measurements for your main control is worth it.