I have successully used my new Promark 3 receivers and GNSS Solutions for static work on several projects, and have had no trouble.

But now I am trying to process yesterday's static work. I set four control points (let's call them 1, 2, 3, and 4). I have only two receivers, so I first occupied points 1 and 2, then 2-3, 3-4, and finally 4-1 (I called 1 "5" for this 2nd occupation of point 1).

When I download the data into GNSS and look at the time view window, all looks well except the occupation of 1-2 shows a dashed line. The dashed line begins and ends at the correct time. But I haven't seen this dashed line before. I 'm sure it's not a good sign, though! Does anyone know what it means? I'm talking about the time line, not a vector.

I think I found the problem. I had entered the wrong antenna height and some other wrong info at point 1.

We'll see what happens now.

Wrong antenna height can really skew the solution.

You may have a problem trying to rename Point 5 as Point 1. GNSS Solutions sometimes gets persnickity about it and sometimes it tells you you have 2 different point names for the same point.

Paul in PA

Lawrence,

After processing (before adjusting), point "5" differs by <0.01 horizontally from the coordinates of point "1".

So I'm satisfied with that. But for some reason, I'm having a hard time getting it to do the "check loop closure". It's not letting me select all four vectors. Could that be because the second time I occupied point "1" I called the second oppupation point "5"?

You need to use the same Site ID for both occupations of point 1.

The software may fuss at you a little for attempting to change it but it will allow you to do so. Be certain to run a new adjustment after you make that change.

Since you used "5" for the Site ID for the reoccupation of point 1, you do not have a closed loop because points 1 & 5 have slightly different positions in your solution.

Yes, Jerry, it helped when I changed the site #.

Also, another problem I had was that the vectors were so close together, I was selecting the wrong vector.

Thanks.
Modified By Compass Rule on 1/30/2008 at 1:11 PM

You really do not have to give the point a different name to make the accuracy comparisons.

Use the repeat vectors tab to evaluate different measurements to the same point.

You can also exclude a vector to see what difference it makes in the adjustment.

If you have one name for one point on the ground it makes loop closures easier and takes advantage of all your measurements in the adjustment.