DJI Phantom 4 RTK with D-RTK 2 mobile station

wxfloyd · Jan 16, 2019

Hello everyone. I'm researching drone platforms for mapping, and my company is considering a Phantom 4 RTK, with the D-RTK 2 mobile station. I'm trying to get an important question answered, but haven't been able to so far.
If I have the D-RTK 2 mobile station, does it require a previously surveyed point for its location, in order to get RTK corrections when flying? Ideally, with my type of work, I would like to show up to a site, set up the D-RTK 2 station, begin my flight with the Phantom 4 RTK, and get RTK corrected location with the drone and ground station. If I have to survey a location for the D-RTK 2, then that would add to the complexity and time for the job. I was hoping that this setup would reduce that time so I can fly multiple sites in a short time.
I understand that I can use a wifi hotspot to connect to a correction network (assuming there's one available for the area I'm working), but some of the sites I would be working at have little to no cellular coverage.

If anyone here has any knowledge or insight on this, it would be greatly appreciated.

MavicMapper · Jan 17, 2019

Yes it would have to be set up over a control point that was previously tied in to a coordinate system

Florida Drone Supply · Jan 17, 2019

We have these units in stock (including the ground stations) and have been testing them locally in FL. While we have mostly been using a connection to an available network, the announcement promised a PPK workflow for when no network was available. We have not tested this yet, but I have reviewed the information on a workflow of this type at the following link: Phantom 4 RTK - PPK Processing Workflow | Aerotas: Drone Data Processing for Surveyors

They do suggest a ground control or check point to measure the accuracy of your finished project, but you could perform this process without one. I think you would be sacrificing your ability to prove or provide an accuracy report without it - but it would allow for RTK corrections without being tied to a public or subscription based network.

I hope the link helps and if you choose to pick up one of these units, please keep us in mind.

Direct link to the product: Phantom 4 RTK with Ground Station

Best of luck to you on your research and let us know if we can help at all.

wxfloyd · Jan 18, 2019

Many thanks for that link! I am also looking into PPK options. We're not necessarily looking for survey-grade accuracy to be reported. Our main goals are to create 3D point clouds that can be tied into ground-based 3D scans, and to provide georeferenced aerial imagery for general mapping purposes.

Florida Drone Supply said:
We have these units in stock (including the ground stations) and have been testing them locally in FL. While we have mostly been using a connection to an available network, the announcement promised a PPK workflow for when no network was available. We have not tested this yet, but I have reviewed the information on a workflow of this type at the following link: Phantom 4 RTK - PPK Processing Workflow | Aerotas: Drone Data Processing for Surveyors

They do suggest a ground control or check point to measure the accuracy of your finished project, but you could perform this process without one. I think you would be sacrificing your ability to prove or provide an accuracy report without it - but it would allow for RTK corrections without being tied to a public or subscription based network.

I hope the link helps and if you choose to pick up one of these units, please keep us in mind.

Direct link to the product: Phantom 4 RTK with Ground Station

Best of luck to you on your research and let us know if we can help at all.

Dave Pitman · Jan 18, 2019

@Florida Drone Supply I am seeing some reports that the native capture app used by the p4rtk is not nearly as good as those available through the sdk. And that currently, there is no way to use one of those other apps. Can you confirm if this is true?

Florida Drone Supply · Jan 19, 2019

Dave Pitman said:
@Florida Drone Supply I am seeing some reports that the native capture app used by the p4rtk is not nearly as good as those available through the sdk. And that currently, there is no way to use one of those other apps. Can you confirm if this is true?

Hello Dave. As for the quality, that is probably true. This is another instance where DJI controls the hardware and software. The app however is even different than the one for mission flying in the newest Pilot app. The P4RTK uses their own GS RTK app.

First, if it would be helpful we could record and post some screen shots or video of the GS RTK app for those who have not had the chance to see it yet.

Second, Is there a particular mapping app that you prefer - we might be able to outline some differences for you as well.

Just let us know what we can do to be helpful and we are happy to do our best to accommodate!

Florida Drone Supply · Jan 19, 2019

wxfloyd said:
Many thanks for that link! I am also looking into PPK options. We're not necessarily looking for survey-grade accuracy to be reported. Our main goals are to create 3D point clouds that can be tied into ground-based 3D scans, and to provide georeferenced aerial imagery for general mapping purposes.

Gotcha...it sure sounds like that can be accomplished without too much difficulty.

Dave Pitman · Jan 19, 2019

I typically use Map Pilot, or Drone Deploy capture, for the missions. DJI's apps have never performed as well or are vetted as well as Litchi, just for an example. And DJI usually looses interest in them in short order.

I don't have any experience with the p4rtk, but it sounds like DJI is shooting itself in the foot again if it does not allow 3rd party apps based upon it's own sdk.