Applying base shift multiple times

Emlid Flow & Emlid Flow 360 Survey tools
1

Hi Emlid Community,

Concerning base shift function, in order to apply more than once, do you delete the previous one and then repeat the procedure? Is this the correct way to do it?

I tried applying base shift a second time and there seemed to be a bigger error. Am I doing it right?

3

Hi Nicolas,

The base shift changes the current base position. So, you need to remove the previously used base shift before applying a new one.

I’ve just double-checked that in the latest ReachView 3 7.6, the app asks to remove the current base shift before you can add it again. Are you working with an older app version?

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6

Thank you for your answer.

I´m indeed working with app version 7.6.

I guess my initial question concerns the correct procedure as to how to apply base shift multiple times in a project. I´m currently working on moderately dense vegetation conditions and irregular topography, so the Lora connection wanes quickly, losing FIX correction. I´ve tried compensating by decreasing the baseline, moving the base closer to the required to-be-surveyed points, applying base shift. The first base shift worked fine with minor calculated displacement, but the second base shift has a 7.3m total displacement which seems a bit much to me…or is this an acceptable error?

What I´ve done so far is average single my initial base position for 15min aprox, then survey whatever points I can with a FIX correction. Then I would apply base shift following the procedure described in the videos by @TB_RTK (thank you!). Since I´ve had to return multiple times to the site on different days (and I can’t leave my equipment onsite), I reposition my base on the same spot as the previous day and manually add the base coordinates calculated the day before. I would then continue with my survey. Is this the correct procedure?

Thank you again for your answer and hopefully I´m not being too confusing. Regards

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8

Hi Nicolas,

The shift is applied only to the points collected after Base shift is turned on. So, the workflow looks as follows:

  1. Place the base and average it with a Single solution.
  2. Add the known point’s coordinates to the project.
  3. Go to the known point with a rover and measure it.
  4. Apply the base shift using the known and measured coordinates.
  5. Collect points.

More details are in our How to apply base shift guide.

You can leave the base shift applied and continue collecting points in the same project on your next visit if:

  • The base is placed at the same point.
  • You’ve entered the Average Single coordinates obtained in the first survey in the Base mode. You can find them in the CSV file – it’s the base’s position for the Measured point.

If you can provide both receivers with Internet access, you can also try out our Emlid NTRIP Caster for correction transmission. It doesn’t require a line of sight between the base and rover, which can be handy in your environmental conditions.

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10

Thank you for your answer. I’ll continue working following the procedure you described. Cheers!

11

Sounds like a plan :slightly_smiling_face: Feel free to share your feedback on how it goes!

1 Like