Hi guys,
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Apologies if this is a basic question but I couldn't find the answer from trimble or other searches. I am wondering about the best practice for transforming survey points in TBC. I am not a surveyor, but have been using a trimble R8 and R10 for to collect topo points at somewhat remote locations so I was not tied into the CORS network (no cell service) or near any monuments. Because of this I set up the base station autonomously for static logging while collecting points with the rover. From testing the static logging on known monuments and sending corrections to OPUS I am pretty confident in the accuracy (tests were within the error range for x,y,z).
Here is my question: The point collection lasted longer than the battery for the base station so I have multiple t02 files from each site. I have sent the t02's to OPUS and have my corrections but I am wondering what is the best practice for transforming the rover points. Should I average all t02's from the entire survey period and transform all the rover points from the averaged point. Or should I transform points collected during each t02 to the individual corrections - such as points 1-100 were collected during the first to2 then points 101-200 were collected during the second t02 and I would transform those separately.
I hope that makes sense. This data is not being used for an actual survey but the highest possible precision/accuracy is the goal. Thanks for your time.?ÿ
Average them.
Think of it this way: if you had gone out and collected static sessions on it first, and then processed and gone back out to shoot your topo, you would average them and start the base with that coordinate, and run all day like that. This is no different except that you are reversing the order.
In other words the base has one POSITION, even though you've measured more than one COORDINATE due to normal random error. The best solution for that position is an average of the measured coordinates.?ÿ
Thanks David! That makes sense. I appreciate the help.
If you're using TBC why are you even using OPUS? Just use the Internet Download feature in TBC to grab concurrent data from the nearest CORS station(s) as well as orbital data and process it yourself. TBC will not only calculate a weighted mean for the point but will also provide a detailed report that shows you how well everything fits together.
Resolve your base point location first, I would expect any "errors" to be in the range of 0.0001" to 0.0003" horizontally, .02' vertically, anything larger would get my attention.?ÿ
Adjust the base point, then fix it in TBC as control, then process the rover vectors to the adjusted base, I will run RTX as a further check on the base, when you run RTX only look at the lat, long, height results.?ÿ
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