I sent some .dat files to OPUS RS last friday and was looking through them today and here is a message from 2 of the solutions (out of the 10 OPUS RS sessions I did).
"Warning - OPUS-RS was able to find a set of reference stations
with data suitable for use with your dataset. However, your position does not fall within the polygon enclosing these reference stations. This means that the geographic interpolation algorithms performed within OPUS-RS must instead perform extrapolation. Extrapolation, especially if your position is far from the reference stations, is prone to error. Use this solution with caution.
Your station is 13.0 KM outside the polygon enclosing the reference stations."
These solutions are independent and random "check points" for an aerial survey following FAA/NGS standards and contract requirements. The area is approximately 36 sq. miles. (6x6). These "random" points are fairly evenly spaced throughout. I estimate no 2 points are more than 3 km apart.
The part in red is what gets me....
I have another check point (closest to the first warning) that did not return the warning message, but had 2 additional CORS stations in the solution (6 common with the other but 2 more). If I were to rough estimate the locations of these 2 points, the one with the 2 additional stations is further from the CORS than the one that spit out the WARNING message.
Should I send those 2 WARNING points back in for another try? They were all over 10 days old before I sent the data to OPUS RS.
This seems rather elementary to me...
Its not so much a matter of distance, its a matter of geometry. If your points do not lie within a polygon connecting the CORS stations used in processing you are going to get this notification.
Jim
Were all 10 done simultaneously? Were the points 100% in the clear?
If cooked under a different constellation or different obstructions, maybe OPUS couldn't be happy with those 2 CORs for a quality solution?
You could select the same 8 under options and see what RS tells you?
> Were all 10 done simultaneously? Were the points 100% in the clear?
> If cooked under a different constellation or different obstructions, maybe OPUS couldn't be happy with those 2 CORs for a quality solution?
> You could select the same 8 under options and see what RS tells you?
No, they were leapfrogged with +/-25 minute observations.
Of the 2 that returned WARNING messages, one was wide open and the other was not. I tried selecting the same CORS manually along with the additional 2 CORS from the "good" point and got a Base line failed message from one of the CORS sites so OPUS aborted the run.
The 2 points mentioned were only measured 25 minutes apart, but that must have been enough time for a major constellation change, that and having a point with about a 15° obstruction in one quadrant "killed" that CORS.
I have another CORS I can try that wasn't used in any solution for the 10 points. Further away than any other station which might put it out of RS reach, but I'm going to try it anyway.
OPUS RS uses a different calculation to process the points than OPUS static. They are trying to do a network adjustment. So they want to see the processed points within a set of parameters and there wasn't enough Cors points nearby to do it. That doesn't mean the points don't have good values. If you can, run a processing session yourself. Since you leapfrogged the points, include those vectors in the processing session and you should get a very good answer. And if there was only one occupation on each point the result will be good locations of the receivers but not the points on the ground. To get that there needs to be multiple occupations of each point.
