Topcon Tools: Typo in RTK base coordinates

[mvanhank222]

How large of an area was surveyed

[felipe-g-nievinski]

Just within a city block

[jhframe]

As for the shift itself, isn’t this just delta N, delta E, delta H? Of greater concern would be the magnitude of the shift — I seem to recall a rule of thumb that every 10 meters of base error introduces 1 ppm of vector error. Not a big deal if you’re talking about 10 meters, but of greater concern if you’re dealing with 100 km.

[felipe-g-nievinski]

Yes, but where exactly in Topcon Tools would the delta values be inserted? If it were in AutoCAD, I’d know how to shift the points.

Thanks for the reminder about the ppm.

[nate-the-surveyor]

What you are talking about is Re-projecting your project. (no pun intended!) Make a coordinate at the center of the earth, and one at the base station. Now, suddenly shift the base station coordinate… now you have a problem!

These are the kind of things that have kept me awake at night! If I’m not mistaken, NGS or somebody has the software to input the perimeters, to perform this. You input the incorrect base sta coords, and all the shots made that day. Then, you modify the base sta coords, and you can see the shift…. Sorry, All I can say is I’ve read about it. Not done it.
I do know that the JAVAD system does JUST THIS… but now I’m running the risk of endorsing some brand… and some folks don’t like that!

As I was saying, the FLOWCHART for Javad goes like this:
Input bad coord for base. Start Survey. Alarm instantly goes off, and SAYS your base station is TOO FAR, from the BASE COORD. UNLESS the coord is REASONABLE, in which case, it will allow it.

(It has algorithms that make it compare an autonomous coord, with what you entered) So, the crew would have caught it right then. UNLESS it was not far off.

But, continuing our story…
Flowchart for Javad:
Set up base, and tell it base is to USE an autonomous coord. OK. It accepts that. Work all day. Return to base, as sun is dipping in the west…
It prompts you to download your BASE RAW DATA to the rover, via bluetooth. At a 30″ interval, all day takes a couple of minutes. Pack up, go home. Put feet up.
Sometime after 11:00 PM, (I’m not too sure the exact time) you turn on the JAVAD LS, and PLUG it in to a LAN connection. Select UPLOAD to DPOS. In about 3 minutes, it comes BACK from DPOS, and says:
YOUR BASE COORD should move UP 6.923 feet, and N82-14-38.96E 4.26′. SHALL I ADJUST BASE, and all shots with it? Tell it YES, and in about 20 seconds, it is all done. RE-PROJECTED. Not just translated, but RE-PROJECTED.
You could get away with a ROTATE and TRANSLATE, and all, IF your “bad coord” was not far from the real one.
BUT, a typo is not selective…. It can buy a bad coord. I’m thinking that TOPCON should have a warning if it is a very bad coord. Does it?

[INDENT=1]Please publish your good and bad coords on this site. Somebody that knows how can tell you more than I can. [/INDENT]

I will say that the Javad MAKES a new coord for EVERY base station, automaticly. This way, it can catch this sort of thing every time. You also have the option for NOT moving the base coord. Like if it says:
YOUR BASE COORD should move UP 0.026′ feet, and N82-14-38.96E 0.019′. SHALL I ADJUST BASE, and all shots with it? You could tell it no. And, to throw out the new base coord. And, it would.
So, it “Keeps a watch” on what you are doing. The DPOS thing is really cool.
IF you entered a wrong HI for the base, it’s going to catch it. BECAUSE it will check each days work, against COORS.

I said all this to say this:
There are folks that can definitively tell you this answer. Stick with it, until you are back in your comfort zone. (ie, is the shift big enough, to warrant a Re-Projection, or will a simple translate be adequate?)

God Bless on your endeavors to make good coordinates!, and Wisdom in interpreting your data!

Nate

[mvanhank222]

I am not sure about how this will work but have you tried editing the base coordinate. If the collector has software( Survey pro does this) that treats the whole job as a linked database you might be able to change the coordinate and everything will shift accordingly. I would back up before you try this I have not and wouldn’t be 100% positive how this will work. I do know that with TS data if you edit a resection point all the associated points will move.

[squowse]

I think if the data collector has recorded positions only (not vectors) then the coordinates will not move.

[leegreen]

You no raw data was collected in receiver. DO you mean Static data was stored?

What software are you suing in the controller? The controller is where you should adjust the data.

In Topcon Tools and in TopSurv, you can edit the BASE coordinate. In TopSurv or Magnet go to Edit >RAW Data >Recompute. InTopcon Tools press F8 to recompute.

Now all of your coordinates created from this base are corrected.

Or you can simply do a translation with any cogo software.

[felipe-g-nievinski]

Perfect, exactly the type of specific instructions that I was looking for. I’ll give it a try when I return to the office. Thanks!

leegreen, post: 348807, member: 2332 wrote: You no raw data was collected in receiver. DO you mean Static data was stored?

What software are you suing in the controller? The controller is where you should adjust the data.

In Topcon Tools and in TopSurv, you can edit the BASE coordinate. In TopSurv or Magnet go to Edit >RAW Data >Recompute. InTopcon Tools press F8 to recompute.

Now all of your coordinates created from this base are corrected.

Or you can simply do a translation with any cogo software.

[felipe-g-nievinski]

So after manually changing the base station coordinates
(e.g., via point properties), just click in the menu
Process > [Re]Compute coordinates. It doesn’t need
the raw observables at all. All shots will move.
Thanks,
-FGN.

Felipe G. Nievinski, post: 349121, member: 10769 wrote: Perfect, exactly the type of specific instructions that I was looking for. I’ll give it a try when I return to the office. Thanks!