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Combining trajectories from PPK for a weighted solution?

  • 1.  Combining trajectories from PPK for a weighted solution?

    Posted 05-05-2020 12:37

    Hello all,

     

    I am afraid I know the answer to this already, but I figured it was worth a shot to ask:

     

    Is there a way to combine trajectory solutions from different reference stations so as to yield a weighted mean for the corresponding points observed in a PP kinematic, continuous points survey?

     

    One of our other offices collected route data with a vehicle mount, and they are looking for final point positions. Being the sole TBC guy in the region, it is now my data to process.

     

    While I have done a fair amount of PPK work using my own base (while far away from any other reference stations) for this particular project we had no base station of our own running. This would not have been my choice, but it was not my project...until it became my project this week.

     

    However, we do have multiple public continuously operating stations in the vicinity of the project. Any one of those stations will give mediocre-to-good results from a single-baseline solution; however, I would much prefer to combine the results of multiple stations and get a better solution. We are also performing static and network RTK work using the same base stations.

     

    Processing baselines with data from the reference stations yields multiple trajectories and updated coordinates for the points that came in from the job file; however, point derivations show that only the first trajectory processed is used to derive the final point position.

     

    The project is set to derive the weighted mean of all sideshot observations, but I am guessing since trajectories are not technically sideshots this does not apply.

     

    I realize that I could turn off "store continuous as trajectory" and manually merge the vectors to get a weighted solution, but I am not about to do that for nearly five thousand separate points.

     

    Anyone have a solution? Or can at least tell me that this is not possible?

     

     

    Thanks!

    -Eric in WA



  • 2.  RE: Combining trajectories from PPK for a weighted solution?

    Posted 11-06-2024 18:38

    Hi Eric, I've got the same question.  Did you find a solution to this?

    Cheers

    Bevan in NZ



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    Bevan Waller
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  • 3.  RE: Combining trajectories from PPK for a weighted solution?

    Posted 11-15-2024 17:25
    Edited by Kyle Calhoun 11-15-2024 17:30

    Hello Eric,

    Realize the other post revised an otherwise dated request. Maybe this response will help others in a similar situation.

    I am going to assume it is not as easy as just running a network adjustment to have the adjustment average out the trajectories. The only other solution I am aware of but have not used myself would be to look into Trimble Applanix: POSPac. I have requested we have the Smartbase feature specifically added to TBC for situations similar to this so we can shorten vector lengths and have a traceable reportable self-created network RTK like solution.



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    Kyle Calhoun
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  • 4.  RE: Combining trajectories from PPK for a weighted solution?

    Posted 11-15-2024 17:49

    It's a great question. Here is the only way I can think of at the moment.

     

    • Process the PPK normally from one of the several CORS stations at a time.
    • Copy the points from the Points spreadsheet to Excel or somewhere else.
    • Reprocess from the next CORS.

     

    You would need to manually evaluate and weigh the multiple point files. At least you would have separate independent measurements to the drone from multiple stations.

     

    I'm glad you asked this question. We had a similar situation where we lost our local PPK base data. Hopefully someone comes up with a more robust solution. I would love to hear other ideas.

     

    Bob Epstein, PLS

    Mobile: 949-279-2226

    Email: bepstein@hunsaker.com

     






  • 5.  RE: Combining trajectories from PPK for a weighted solution?

    Posted 01-05-2025 16:57

    Hi Kyle

    The addition of the Smartbase feature from POSPac would be great and would seem like a good way to address this.

    Cheers

    Bevan



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    Bevan Waller
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