геодезический беспилотник

PRECISE UAV SURVEY WITH DJI PHANTOM 4PRO GNSS RTK/PPK

In the first stage we installed GNSS base station on the point with known coordinates and measured locations in RTK mode of six ground control points distributed over the survey area. (Pic. 1, Pic 2).

GNSS

Pic.1 Topcon GR 5 GNSS base station

 

Ground control point

Pic.2 Ground control point

 

In the second stage a drone mission was planned (Pic.3) , uploaded to DJI PHANTOM 4PRO GNSS RTK/PPK (Pic. 4). The flight mission was performed with the following parameters:

  • survey area 40 hectares
  • flight speed 10 m/s
  • overlap 80/80%
  • altitude 200 meters above ground level.
Location of the survey area and flight routs

Pic. 3 Location of the survey area and flight routs

 

DJI PHANTOM 4PRO GNSS RTK/PPK

Pic.4 DJI PHANTOM 4PRO GNSS RTK/PPK

Stage 3. Photogrammetric processing. After landing, GNSS data were download from the drone via wi-fi and RINEX files from drone and base station were processing together using RTKLib postprocessing software (Pic. 5.). Differences between images locations measured by standard DJI GPS and upgraded GNSS system are shown at Pic.6

центры фотографирования

 

GPST

latitude(deg) longitude(deg) height(m) Q ns sdn(m) sde(m) sdu(m) sdne(m) sdeu(m)

sdun(m)

10:30:57.823

55.42721116 37.09866392 383.2712 1 13 0.0077 0.0049 0.0148 -0.0034 -0.0043

0.0067

10:31:01.823

55.42692354 37.09902841 382.1284 1 13 0.0077 0.0049 0.0148 -0.0034 -0.0043

0.0067

10:31:05.823

55.42663183 37.09938321 380.809 1 13 0.0077 0.0049 0.0148 -0.0034 -0.0043

0.0067

10:31:09.823

55.42634191 37.09974165 379.716 1 13 0.0077 0.0049 0.0148 -0.0034 -0.0043

0.0067

10:31:13.923

55.42604749 37.10009267 378.2999 1 13 0.0077 0.0049 0.0148 -0.0034 -0.0043

0.0067

10:31:18.123

55.42575137 37.10045163 376.7581 1 13 0.0077 0.0049 0.0148 -0.0034 -0.0043

0.0067

10:31:22.222

55.42546214 37.10080242 375.5348 1 13 0.0077 0.0049 0.0148 -0.0034 -0.0043

0.0067

10:31:26.422

55.42516381 37.10116678 374.3488 1 13 0.0077 0.0049 0.0148 -0.0034 -0.0043

0.0067

Pic.5 GNSS post processing report

Pic.6

Photogrammetric processing  was carried out in Photoscan software. Precise coordinates of image position were imported to the project and used for images alignment. Coordinates of ground control points were necessary only for the model accuracy estimation.

The following results were achieved with using precalibrated parameters of focal length F=3642.97108 and GPS offset Z=-0.21. (Pic.7,8,9)

Pic. 7

 

Accuracy of image locations

Pic. 8 Accuracy of image locations

 

 

Pic. 8 Accuracy of GCP location

 

#Label

X/Longitude Y/Latitude Z/Altitude X_error Y_error Z_error

gcp1

37.108468 55.428252 177.5342 0.095565 0.116266 -0.155084

gcp2

37.105661 55.429969 185.2419 0.060218 0.108619 -0.057785

gcp3

37.104604 55.42775 187.5888 0.053902 0.033637

-0.117375

gcp4 37.101668 55.430107 192.0927 0.025702 0.060954

0.020079

gcp5 37.101818 55.425095 191.8068 -0.048562 -0.088709

0.086965

gcp7 37.098997 55.427386 192.1309 -0.051945 0.01491

-0.073903

The results of the project shows capabilities to use a low cost DJI PHANTOM 4PRO upgraded with GNSS RTK/PPK receiver as a survey grade UAV. DJI PHANTOM 4PRO RTK/PPK provides high accurate drone data for precise mapping and 3D modelling. You no longer have to lay down GCPs or just minimize their number, saving countless hours and labor costs.

Demo dataset of this project including RAW GNSS files, images and GCP coordinates is available from
https://cloud.mail.ru/public/LcUW/aPGxNnehc

 

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