DJI Phantom 4 RTK in PPK processing


#1

Hello,
I bought a P4 RTK and thought it would be an easy going but now, after 5 days in suffering, I really need to ask you guys. What is an easy software to process PPK and Update the Pics?
I tried to PPK in LIBRTK, RTKPOST, EZSURV and even in D2Harita. The main problem seems to be the P4 Output. After a flight, I have the Pics and
Eventlog.bin
PPKRAW.bin
Timestamp.MRK
Rinex.obs

The majority of the programs is asking for .ubx data, which seems to be the same like .obs but than not?!?
My best results came from EZSurv. But I have now ~13000GPS points for ~900 pics and no idea how to merge.

Here as Shape


And in CSV Trajectory Export

My sample project contains 3 Runs with following 3 OBS files

If someone could help me I would really appreciate. I can provide any kind of data which is necessary.

Thanks


#2

I am glad someone spoke up on this. I was pretty sure that getting the data straight out of the drone and uploading to DroneDeploy wasn’t going to happen. You can post-process or continue to put a couple of GCPs. 3-4 should work. Just something to get you rotated and scaled correctly.

RTKLIB will do what you need and is free. You will need the base OBS, drone OBS and drone NAV. If you have UBX then you need to use the rtkconv module of rtklib to convert to OBS and NAV.

So what have you run into that makes you think you need to post-process? This quickly turns into something ugly if they are marketing RTK and at the end of the day it is really PPK.


#3

Thanks for the answer,
unfortunately the P4 RTK is not giving you UBX… I have the listed data above, so nav file is missing…
The other thing is the Base station. For my sample it should be 18th Jan 2019 11-14 oclock, Potsdam in Germany POTS00DEU
But all my RTKLIB trys ended in a fail…
I only purchased the P4 RTK to be not longer depended to GCPs… I can never spread as that much I would need… On their Homepage DJI is saying, that PPK is possible… but how is the question and the secrete as well


#4

There may be something in the trajectory folder that is DJI’s version of the NAV file. There are several choices, but I am not seeing any of those files. I am fairly new to post-processing so would it be ok if I linked this thread into the Emlid forum? Or you can start your own. It is a GPS forum so it may be a better resource than here since the RTK is so new.


#5

The P4 RTk is only delivering these files
Eventlog.bin
PPKRAW.bin
Timestamp.MRK
Rinex.obs

The output from Reach m+ is different and all of the P4 RTK PPK suggestions seems to be based on it…

You can link me, where ever you want to, as long I will find some help :wink:

Kindly


#6

GPS files are GPS files and those guys are way more GPS oriented. Sometimes it is something as simple as renaming a file extension since they are all pretty much TXT or CSV in the end. I’ll cross-link back to here as well.


#7

Here we are!


#8

Are you using the DJI base station or a CORS site? Do you have RTK turned off? If you are going to post-process you don’t need that data.


#9

CORS is not available in Europe. My Datasource should be this for POTS00DEU (Potsdam, Germany)
http://www.epncb.oma.be/_networkdata/stationmaps.php

I am working without a base station
RTK is definitely turned off (I cross checked this)


#10

Another piece of software you may want to look at is Geosetter to update your image geotags. It is easier if you have the events log, but it can be done with the full track. It will just be harder to know which GPS point matches a photo.

I’m looking through the files now. Do you have the “base” observation file downloaded? I don’t see it in the Dropbox files?


#11

Thanks, Geosetter is new to me, I will check it out.

The P4 RTk is producing an eventlog, maybe this is suitable?!

The base should be this. The file name fits to an other tutorial I found

(Sorry but my upload is very slow today and I gave all the files to the upload today. I hope it is available right now
)


#12

Yes, I would think the camera events log would be the most suitable. Geosetter will want a tracks file that contains time and lat/lon/elev. This is what I downloaded for Potsdam. So now all we need is your equivalent of the NAV (ephemeris data).

Here’s the options for Geosetter tracks.
image

Can you upload the eventlog.bin?


#13

Here are the Eventlogs for all 3 runs

In all other Tutorials the ephemeris data for nav were included in the ubx…


#14

Ok, found the full track as shown in QGIS. Does this look correct?


#15

Here are the file types for NAV. I am betting it’s one of the highlighted.

image


#16

Yes, this is the shape result from EZSURV but with too many GPS coordinates. The amount is not fitting to the number of pictures. It is much higher (and in the end I would love to work without EZSURV, this is only a try)


#17

I tried also to work with RTKPOST and this drop down bar is familiar to me but I have no .nav file or something from the other …


#18

Yes, that is the actual full tracks of positions from the P4P. This is where the events are better. One file and we can process.

image

After that we will have the events POS and can generate the GPX and finish in Geosetter.


#19

The Shape is the executed PPK process from EZsurv, so it should be the result from RTKPOST right?
But where can we get this .nav data from? Or is there a converter to mentioned formats?


#20

The result you are going to want is the track to bring into Geosetter. Whichever of those format you can get to. From rtkpost it is the GPX and seems to be preferred in Geosetter. I’ve got to head out for now, but will jump back on this evening (morning coffee for you?) :slight_smile: We will find the NAV equivalent. I still keep looking at the Trajectory folder…