If your not comfortable doing the work for the precise work, I would hire a professional surveyor that has experience doing this work. They would know the areas where the needed GCP’s would be optimal for your project. Then maybe he would guide you in the proper process from beginning to end.
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The recommended maximum PPK baseline is 100km. With PPK using RS3, you can achieve positioning accuracy of H: 5 mm + 0.5 ppm and V: 10 mm + 1 ppm.
So, for the 45km baseline, the expected accuracy is ±27.5 mm for the horizontal and ±55 mm for the vertical. Please note that this level of accuracy only represents ideal conditions. You need to consider environmental conditions, atmospheric conditions, and such.
Would you recommend me to hire a surveyor to take those GCP very precisely or it’s overkill for my project?
Hiring a surveyor can definitely help you get started. Using new equipment and post-processing the data can be tedious and time-consuming, and fieldwork sometimes involves a lot of trial and error.
If this project is urgent, I suggest hiring a surveyor and learning as you go.
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100km?! We have been told for years that 60km is the recommended maximum. What’s changed? I don’t think the accuracies you stated are realistic. Rarely can you get better than 1/1.5cm HV with a PPM adjustment of 0.5mm and 1mm/km HV. This would put you at 3.3/6cm HV on a good day. This has been proven to be much more realistic in our experience.
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I’ve said this for years, short baselines are best for any GNSS projects. If your in the middle of nowhere, you can PPP your data, get a precise coordinate and post process your data from the new base.
Short baselines are more accurate and are your friends
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As pointed out by others above, you can create your own base point by setting up an RS3 over a solid, permanent, fixed point for many hours and then run the log file through OPUS to obtain the real world coordinates. I’m not a surveyor so I usually have a PLS check my base point and a few of my control points at each new project (to satisfy any questions that may arise in the future) and have been quite impressed with the RS3 results compared to the surveyors who typically use Trimble R10 or R12 equipment for their checks. During a recent check of one of my RS3’s base point results (after 7 hours on the point with the RS3 Base), the surveyor’s results (they also process in OPUS) matched my coordinates to 1cm horizontal and 1mm vertical which was pretty good considering the RS3 is typically expected to be accurate to 1cm at best. When needing to set up the RS3 over a base point again, I simply enter the base point’s lat/lon coordinates manually into Emlid Flow during the RS3 Base setup, enter the rod height, and am good to go with the RS3 Rover (or RTK drone in your case). Also, absolutely ALWAYS set multiple ground control points for drone photogrammetry (I’m still using a Phantom 4 RTK with a D-RTK2 base). You will get surprisingly good and repeatable point cloud results for ground surfaces. Stuff sticking up above ground can sometimes get a little goofy in the point cloud. Best of luck.
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You manually enter the point every time? Why not shoot in another base point with your rover, switch and shoot in the original base point and then just occupy it from the project moving forward?
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Hi Michael. I’m missing your point of shooting another base point and then switching. When I have a project area and I’ve established a permanent base point, (my projects are generally remote with no cell phone service) I’ll go back to the project site (e.g. for doing some river or pond earthwork), set up the RS3 Base over that base point and then use the RS3 Rover to check elevations or shot additional points as needed. Since I know the coordinates of the permanent base point, it takes only a minute to Manually enter those coordinates into Emlid flow and then I’m off and running to shoot points with a Rover. Is there a work flow that I should be considering with the RS3s? What I’ve indicated above is similar to what I’ve been doing for twenty years by resectioning with a robotic total stationing on multiple control points. Now, things are much easier with the RS3s. But, it appears that I’m missing something. Thanks.
This process is just to make occupying the point easier by simply selecting a point to occupy instead of entering 20-30 characters manually and removes the chance that anything is entered incorrectly.
Do your normal setup
Set a nail or some other monument and locate it with the rover
Move you base to the new point
Shoot the original base point with your rover
Now you can just select the point in base settings instead of manually typing it in every time.
- Choose Base Settings
- Make sure Entry Method is set to Manual
- Click Configure
- Click Choose from project
- Choose the project
- Choose the point
- Click Apply
- Click Save
Here’s the Emlid Doc. You can skip down to point 5.
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Got it. Thanks! It is sometimes stressful to enter the coordinates correctly and to stay focused when you’re in the field and weather’s beating down on you. I appreciate your input and will give it a try.
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Hello,
You all helped me a lot to clarify the process, thanks for that!
I have another question…
Drone: Mavic 3E
Base: RS3
I will have a surveyor to setup a permanent point for my base and permanent GCP.
I would do RTK and then PPK. Is that a good workflow, or I should only do PPK. (I’m not sure that RTK is going to be reliable because there is a lot of iron ore and steel structure around and in my project).
Thanks,
JP
Hi @JPGraphX,
You can try RTK first; if you find that the quality is not good, you can always do PPK.