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D-RTK 2 base station co-ordinates
4596 8 2022-9-15
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rob_s85
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Flight distance : 1115 ft
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Is there a way to find what the D-RTK 2 base station thinks its location is for a given survey, please?
I have flown some repeat surveys for topographic change detection, and had to switch the base station off between surveys to save the battery, so each survey has an XYZ offset. Presumably if I can find the co-ordinates of the base station for each survey I can calculate the offsets quite precisely (absolute accuracy is not important).

I assume that the base station fixes its location whilst on. For other repeat surveys I left it on and don't have the same problem, or any obvious drift.

I flew the surveys with the standard base station setup (I realise it is possible to assign the 'real' base station co-ordinates).

Thanks!
2022-9-15
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patiam
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You can pull the logged files off of the D-RTK 2 using Windows or DJI Assistant:

D-RTK2 Mobile Station stores GNSS data (satellite observation, broadcast ephemeris and calculated coordinates) in its internal memory as .DAT files. You can find them into the following directories (DF 184788) (DF 188122) :
/log/rtcmraw
/log/userlog0

To download them:
a)switch on the D-RTK2 receiver;
b)connect the D-RTK2 to your PC using the USB-C cable;
c)read the D-RTK2 internal memory as an USB storage device.
They can also be exported from the D-RTK2 receiver using DJI Assistant 2 for Phantom:
a)switch on the D-RTK2 receiver;
b)run DJI Assistant 2 for Phantom;
c)connect the D-RTK2 to your PC using the USB-C cable;
d)use the “Log Export” function
DJI Assistant 2 > Log Export > RTCM Data > Save to Local
rtcm_log dir > .DAT (binary) RTCM 3.2 raw data
DJI Assistant 2 > Log Export > User Log > Save to Local
user_log dir > .DAT (ASCII) (GPS time, lat, lon, hgt, std)
DJI Assistant 2 > Log Export > User Log > Save to Local
EXPORT_FILE_2019-11-14_16-40-52.DAT (bin) ??
In the /log/rtcmraw (D-RTK2 directory) and \log_export\rtcm_log (PC directory) you find binary .DAT files in RTCM 3.2 MSM5 format containing raw satellite data.
In the /log/userlog0 (D-RTK2 directory) and \log_export\user_log\ (PC directory) you find .DAT files in ASCII format containing the position of the antenna phase center (APC) calculated by the D-RTK2 receiver at each epoch.
RTCM 3.2 raw binary files
File name structure: RTKnnn_YYYYMMDDHHMM_code.DAT
File type: binary
Directory: /log/userlog0 or \log_export\user_log\
Example: RTK027_202002211100_13ALG630050025.DAT
These files are in RTCM 3.2 MSM5 format (DF 188122) and contain raw satellite observation data and broadcasted ephemeris data.
It is possible to convert them from RTCM 3.2 to RINEX format using a third-party tool (e.g. RTKCONV and CONVBIN tools available in the RTKlib and RTKlib demo5 software suites) (DF 202392).
ASCII DAT files
File name structure: RTKnnn.DAT
File type: ASCII
Directory: /log/userlog0 or \log_export\user_log\
Example: RTK049.DAT

The RTKnn.DAT file contains in each raw (i.e. record) data about the x,y,z position of the antenna phase center (APC) calculated by the D-RTK2 receiver (one every 200ms = 5Hz)
Example:
during initialization, when not enough satellite data have been recorded yet...
bestpos:0,0ms,type:0,lat:0.000000000,lon:0.000000000,hgt:0.000,std(0.000000,0.000000,0.000000)
bestpos:0,0ms,type:0,lat:0.000000000,lon:0.000000000,hgt:0.000,std(0.000000,0.000000,0.000000)
…after the first GNSS positioning solution...
bestpos:2082,133858200ms,type:16,lat:40.838071183,lon:14.364137186,hgt:193.776,std(1.469309,1.049694,2.386449)
bestpos:2082,133907000ms,type:16,lat:40.838053814,lon:14.364128258,hgt:196.118,std(1.663673,1.278624,2.781688)
...after averaging the found solutions...
bestpos:2082,133908400ms,type:1,lat:40.838053603,lon:14.364117239,hgt:197.287,std(0.000000,0.000000,0.000000)
bestpos:2082,133908600ms,type:1,lat:40.838053603,lon:14.364117239,hgt:197.287,std(0.000000,0.000000,0.000000)
bestpos:2082,133908800ms,type:1,lat:40.838053603,lon:14.364117239,hgt:197.287,std(0.000000,0.000000,0.000000)
...
Here the description of the content of each field in the record:
Field 1
GPS week of the recorded GNSS observation (i.e. calculated position) in UTC time
Field 2
Milliseconds of the recorded GNSS observation in UTC time, with milliseconds expressed in GPS time format (i.e. milliseconds from the beginning of the GPS week)
Field 3
Positioning type flag. 0: no positioning; 16: single-point positioning mode; 1: averaged position (single point mode); 34: RTK floating solution; 50: RTK fixed solution
Field 4
Latitude (lat) of the of the APC, in degrees
Field 5
Longitude (lon) of the of the APC, in degrees
Field 6
Height (hgt) above the reference ellipsoid (h or Hell) of the of the APC, in meters. Not to be confused with the orthometric height (i.e. altitude above mean sea level).
WGS84 is the default ellipsoid. When using the "Custom network RTK" Service Type, it can be set to another ellipsoid by choosing the appropriate Mount Point of the NRTK service.
Field 7
Standard deviation (in meters) of positioning results in the north direction
Field 8
Standard deviation (in meters) of positioning results in the east direction
Field 9
Standard deviation (in meters) of positioning results in the vertical direction

Thanks to M.Buonanno for compiling the D-RTK2 - User Notes!!!
2022-9-15
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DJI Natalia
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Hi, there.
We have confirmed your problem with the relevant team and will keep you updated here asap, please don't worry.
2022-9-16
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rob_s85
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Flight distance : 1115 ft
United Kingdom
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patiam Posted at 9-15 12:23
You can pull the logged files off of the D-RTK 2 using Windows or DJI Assistant:

D-RTK2 Mobile Station stores GNSS data (satellite observation, broadcast ephemeris and calculated coordinates) in its internal memory as .DAT files. You can find them into the following directories (DF 184788) (DF 188122) :

Thanks, this is amazingly helpful!
2022-9-18
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DJI Natalia
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rob_s85 Posted at 9-18 10:58
Thanks, this is amazingly helpful!

Update:
Sorry for the late reply.
We hope your problem is already resolved.
Our engineer said the reply from patiam is right. After transcoding dat into rinex, you can see the base station coordinates in ECEF format in the metadata, you can also search the standard documents of rinex.

Besides, if there is anything else that we can help with, please feel free to contact us.

2022-9-18
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djiuser_nWSN3OrvjME2
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I just tried exporting dat files from an RTK-2 base station using the latest dji assistant 2 enterprise and it wrote zero size files.
I copied the .dat files just using the drive that pops up - and the files are not recognised by RTKconv - any ideas on using the recorded files for RINEX post processing?
its really not documented anywhere I can find
2023-5-23
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kirdji
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if you find this thread  - be aware that the .dat files on the dji rtk-2 are RTCM3.2 MSM5 binary format
if you edit .dat to .rtcm3 RTKlib converter can convert them to RINEX OK!
2023-5-23
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patiam
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Flight distance : 1093865 ft
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kirdji Posted at 5-23 05:47
if you find this thread  - be aware that the .dat files on the dji rtk-2 are RTCM3.2 MSM5 binary format
if you edit .dat to .rtcm3 RTKlib converter can convert them to RINEX OK!

I think I said that last year...
2023-5-23
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kirkmart
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yes and it was very helpful ;-)
is there another thread on dji rtk-2 processing?
2023-5-24
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