GCP with RTK NTRIP + UAV PPK

Hi,
I use 1 UAV with a PPK system and an RS2 + NTRIP to place GCPs.
So I understand theses 2 system use 2 different network:
RS2 use a NTRIP network and UAV is post corrected (I do not use the RS2 as base).

Is there any recommandation about using the same network? Should I link my UAV with RS2 as base ?
thanks for help !

Your flow should be like this:

  • Arrive on site
  • Set up your base, and leave it running with raw/rinex logging on. This setup could include averaging a 5-10 min fix from the NTRIP network for your base-location.
  • Set-up your rover to receive corrections from your own base
  • Place your GCP’s
  • Fly your mission
  • When back in office, process the UAV-data against your own base, using the Base Coordinates derived from the 5-10 min fix averaging.
  • Your GCP’s and UAV positions are now aligned.
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Thanks for helps,

I have few noobs questions:

  1. What would be the workflow for a very large site for which I plan several/differents days to fly and place GCP ? Another situation I will meet is : I use one day for placing some GCPs , and another day for placing the last GCPs ?

  2. I’m not sure to really understand : will it work with only 1 RS2 ?
    In my case I only own 1x RS2 + NTRIP suscribtion and 1x UAV with PPK system.
    can you correct me if I’m wrong:
    I should use the rinex of the the same base to correct both my GCPs position and UAV data?
    then I should : place a my rover (RS2) in NTRIP for 10min at the point an scale the derivation from the BASE (free online base) . Then I use the same BASE to correct my UAV data?

if you can give more details for theses two points:

  • Set up your base, and leave it running with raw/rinex logging on. This setup could include averaging a 5-10 min fix from the NTRIP network for your base-location.
  • Set-up your rover to receive corrections from your own base

thanks

Since you have access to an RTN system (NTRIP), your first step can be GCP placement and it doesn’t necessarily matter if they are taken on different days. The main issue will be your baseline with the receiver from which you get the correction, which will dictate your absolute accuracy. It all depends on how accurate your project needs to be.

When you’re ready to fly your mission, set your RS2 up on a fixed point, and record the raw log, making sure you have a little bit of extra data at the beginning and end of your aerial mission. Since you know the position of your base from the RTN service, doing the 5-10 minutes average before the flight will help narrow the position down (you can enter that value as a manual coordinate entry after averaging).

When back at the office, you can post-process your aerial raw log against the fixed RS2, then you can use your GCPs to further realign the images in your photogrammetry suite.

That’s how I would do it anyway.

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Hi @ziok,

It seems that the Christian’s workflow will work if you have 2 Reach RS2. With 1 unit, you can try the following workflow:

GCPs collection:

PPK workflow:

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Hi everybody,
Everything seems to be much more clear now, thanks you so much !
Your team & community is really powerfull.
I’m happy to have bought this stuff from your brand !
See you later !

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About the PPK uav workflow:
There is a case in which this workflow will be not easy to reproduce is the case when I have to move my base at every flight I’ll do:
I’ve a mission for which I need to do 12 flights, and I will move at every flight and change my takeoff place (and also my base if I use a mobile one). Then, with this workflow I’ll have to wait 5-10min *12 at each takeoff place … and redo the process at every battery…

Is there another way get aligned datas?
I’m noob but I do not understand why I should use the RS2 as base for the PPK (UAV) process?
I mean, the remote base (that I paid for my NTRIP RTK service) could also record rinex and using the same reference like the one used for the GCPs collect with RS2 RTK?

thanks !

You can leave it if you want, but shorter baselines are better.

If you are using a dual frequency receiver, you might get away with a shorter time. And if your flighttimes are beyond 20 minutes, you can probably get down to a few minutes (basically the time it takes before you and the drone is ready).

Because short baselines matters. You will see poorer results the further your baseline is. In example, the RS2 in kinematic mode has a precision of 10 mm + 1 PPM, so with an 80 km baseline, you are looking at 90 mm of precision, where as if you use your own base, you will get 10 mm + 1 mm or so.

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Hi @ziok,

Reach RS2 can provide centimeter-accurate coordinates on distances up to 100 km in PPK. If the NTRIP base is within a 100 km radius from your site area, you can use logs from it for post-processing instead of a second unit.