DJI Phantom 4 RTK in PPK processing


#41

Hmm, just one more thing to the agenda. It was supposed to stop doing that with the drift-turn method.


#42

Where to find this page?
It is all without GCP, I don’t have some and it is very important for me to work without.
The Alignment will process again in generic. Everything else would need to long…
Does anyone know if there is a way to update the coordinates of the Pics with the PPK CSV? Is that possible in the Geosetter? If yes, what is the name of this function? As MichaelL postet in the Screenshot?


#43

Ok, so since GCP’s were not used 8cm is the same result I was getting without. I think we can get that down to 5cm, but that is pretty much what is expected without GCP’s.

Yes, Geosetter is the program you will want to use. You will need one of these file types as the track of the PPK events. I use the GPX from RTKLIB.

image


#44

The page showing the components of the error is accessed with the middle icon of the 3 table icons on the right side of the Reference page:


I show an example from one of my missions with an ordinary Phantom 4 Pro.


#45

Try this Processing Program. We’ve been working with Klau over the last couple of years and it now does just about everything required. It now works with the P4P RTK for post processing


#46

It’s kind of spendy. I think you can get the P4P L1/L2 Loki hardware kit and processing software from GeoCue for under $6k

It’s kind of disappointing that DJI doesn’t include any PPK solution with the P4RTK.


#47

What kind of base station does Klau use?

I’d like to see a model and 3cm accuracy off of this, " With Klau PPK direct georeferencing, UAVs can cover larger areas in a single flight by reducing the side overlap down to 40%."

P4P w/ Emlid Reach RS+ base, M+ mobile PPK and post-processing solutions. $3000.


#48

Actually, you can use other base stations not just the DJI one. We have actively used two different models from two different regular GPS manufacturers to conduct live RTK missions with a P4RTK drone giving 2cm-2.5cm H and V RMS results (using no GCPs, only CPs + a vertical transformation to get to local datum).
We have this set up in NZ/Aus.
Your base needs to be capable of casting NTrip data, usually using a data sim card.


#49

Klau uses more or less any base station. Ie yours, not theirs.

I may have some models with 3cm or better accuracy, but not sure if they are mine to give out.

I do have 2-2.5cm models from P4RTK using network GPS. Still need 1 GCP to get the ellipsoid-datum separation right (I feel there are likely systematic errors in the photogrammetric processing that can’t be predicted accurately until first processing, but can be eliminated by adjusting to GCPs or average CP RMSs) or even better, 3-4 GCP around the site corners to get sub 2cm results.


#50

Thanks for that @Corbon. So it will work with any base - that can NTRIP, but does not come with a base. Anyone who knows anything about GPS knows that as distance increases corrections and local accuracy suffers.

The drone itself is $13k and includes the PPK software. Or the PPK software can be purchased for $4k standalone.

To each their own, but I can get sub-3cm RMSE’s with a standard P4P and full program of GCP’s or with my Emlid PPK with 3-4 GCP’s. Post-processing software is free and I could build 4 of a similar setup (including base stations) for the same cost.


#51

For sure, although the P4 RTK version with no PPK software costs closer to USD6-7k here. Many surveyors already have network subscription licences which they can use to get RTK corrections, and if they want to maximise precision they can use their own base if it has the capabilities.

The savings in time and safety can cover themselves in one project sometimes, in less than a month of regular use most times.

As you said, to each their own. Different folks have different needs and values.


#52

Thanks for the information. I will ask Klau for free trial.
Which photogrammetry software are you using or is it included in Klau?
Currently my main problem is still, how to process the ppk data and the drone images to one pointcloud…


#53

Hi Hirschred.

I use Pix4D (certified trainer and Reseller, full disclosure) and occasionally Agisoft. (I’m a member of this forum because we used DD for data capture for a while).

I’m not trying to sell you anything, but my perspective is from a professional surveyor (my training and background) using relatively costly but properly professional software.

Results with both Klau PPK (PPK processing inside Klau’s software which then applies the processed positions back to the image EXIFs) and DJI P4RTK have been excellent with proper professional software.

In the end, I’m a believer in the ‘you get what you pay for’ mantra. But everyone has different drivers. Because most of the people we work with are professional surveyors who already use costly tools and processes and charge accordingly, we are usually not entirely driven by the lowest cost option but by professionalism and efficiency.

We also incorporate post-processing systems (eg data cleaning, production of volumes, contours, TIN Models), which we often recommend different software for - drone data tends to overwhelm most professional CAD systems that surveyors use and the data thinning systems used by photogrammetry programs tend to be very poorly designed in terms of keeping key data points and dropping the irrrelevant chaff in between.

Klau PPK comes with its own software which is at a very well developed professional level now. You can purchase the software separately., but its a proper professional tool at a proper professional cost. You need a steady volume of work to make it cost-appropriate I guess.
I haven’t used at all that often to be expert in it. Just enough to be able to train others in how to get the job done. P4RTK has kind of blown the PPK market away really.


#54

Great commercial! Pix4d definitely has some very capable software.