dear colleges
Hope you're doing well ....
I'm working to create a new group of control points, and the new CPs have already been observed by the GNSS Static and processed.
Now I want to convert them to the ground points by the total station traversing by a redundancy way ( to observe each point from set-up station in sequence for all)
My question as the first time I'm working with this method, is :
- Which measurements do I need to collect from the site (distance from point to other, angle, bearing ...etc? )?
- Which software is better for processing?
- Did I need to include the main official BMs with the new traverse points?
Thanks to everyone who gives a comment with helpful ideas .....
I use "StarNet" to do this sort of thing. Others use "Trimble Business Center" (TBC) or Leica's "Infinity". And there are others. They all work more or less the same.
You should traverse through your control points in the normal fashion, collecting horizontal and zenith angles, slope distances, and measure ups for instrument and target. Use the same point numbers for the points that you used when GNSSing them. Assemble this traverse data together with the GNSS vectors into a single simultaneous adjustment.
Yes, you should include ties to elevation benchmarks in your data.
When using Least Squares you can add any reasonably accurate measurement you have, along with its probable error. You are not limited to a traverse.
Depending on the relative locations of your point, it may be beneficial to include measurements between other pairs of points. An example of this would be in a long, narrow loop traverse. Measuring across the middle of the loop to make a figure-8 can improve the accuracy of the middle points relative to each other.
Hold the horizontal positions from the static survey, use a level to firm up the elevations. We use TBC to adjust level numbers, StarNet is also an excellent program. If you need to fill in, the Total Station can be useful, tie into the static control and adjust. I don't readjust fixed control once it's finalized unless there is movement (rare). Todays GNSS receivers are very accurate, there should be no need add TS numbers to them horizontally, use the TS for checks, you should always be within .5cm. With any distance between points the GNSS numbers will be superior. If you're only doing a building or small site it might be arguable, but I doubt your turning angles with a T3.
Not sure what you mean by ground points. There are any number of ways to do that from GPS data and none of the good ones involve a Total Station.
Be sure that you have defined what coordinate system you are working in. GNSS will be converted to some projection which has a scale factor and may be presented at the ellipsoid instead of the ground surface. Total station measurements are at ground. People often run into discrepancies because of mixing those data sources without properly specifying them.
Welcome to these forums. Thanks for posting this. We will be starting a topographic survey next week after we recover and locate the remaining boundary corners. What are the precision requirements for your project?
@field-dog hi mate you're welcome
It's high precision around 2mm