D-RTK Misnomer

DXB_Inspire · Aug 12, 2016

When we see the letters RTK we expect it to be a survey grade capable instrument. Typically this would involve setting up a base station over a known point, inputting the station coordinates and then transmitting the corrections to a rover, thus providing a high accuracy kinematic solution thats tied into a coordinate system.

Having read the materials on the D-RTK system, it appears that the survey accuracy has not been accounted for. Yes there is a base station, but it doesnt allow for setting up over a known point. It transmits its coordinates to the air system mounted onboard the M600. Whilst this is technically an RTK solution and the positions of the drone will be accurate relative to the ground station, there is no facility to tie the ground station into a coordinate reference system. So the resultant images that have been geotagged will not be cm accurate with reference to a national grid. Also theres no ability to receive corrections from a transmitted VRS system from what I can see in the available documents.

Therefore, from what I have read, its NOT a survey grade RTK system.

dasko · Sep 5, 2016

this is ridiculous........... whats the point ?? to have cm accurate filming lol nice

davehrot · Sep 8, 2016

Any update from actual users of the Rtk system regarding use for mapping applications

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DXB_Inspire · Sep 9, 2016

From what I can see, the kinematic position is relative to the base station, but the base station does not have the facility for tying into a national grid.

Also you would expect to see the antenna mounted on a tribrach with optical plummet.

I guess it's probably great for accurate hovering, but it kind of misses the whole point about high accuracy positions being recorded in the EXIF data of the images and then post processing the data to take into account the base station logged positions.

dasko · Sep 9, 2016

Dear Jason,
Thank you for contacting DJI Technical Support.

We can enter your own base station's coordinates into the assistant software.
But to update the coordinates related to your own base station, we need to wait for next firmware.

Thanks for choosing DJI.
Best Regards

DXB_Inspire · Sep 9, 2016

As usual, about as clear as mud!

erikgraham · Sep 25, 2016

Not a map guy but I'm curious why it isn't good enough to be able to enter the coordinates into the base station. Isn't that effectively the same as placing the base station over a known point?

DXB_Inspire · Sep 25, 2016

A survey grade base station receiver sits on a tribrach mounted to a tripod. It is levelled over a known point by sighting the bench mark through the tribrach eye piece and slewed into place.

Have a look at the specs for a Topcon HiPer SR for example.

Once set up you also need to enter the antenna height and use the phase center value of the antenna as well.

erikgraham · Sep 25, 2016

DXB_Inspire said:
A survey grade base station receiver sits on a tribrach mounted to a tripod. It is levelled over a known point by sighting the bench mark through the tribrach eye piece and slewed into place.

Have a look at the specs for a Topcon HiPer SR for example.

Once set up you also need to enter the antenna height and use the phase center value of the antenna as well.

Ok. First let me say that's kind of fascinating, but second let me curse you for piquing my curiosity with words like "tribrach" and "slewed." You've likely condemned me to many many hours of Google and Wikipedia research and reading. The quest for knowledge I'll never use.

But to sum it up in an oversimplified way, what your saying is that you are doing a lot more than just "placing" the base station over a known point.... and whatever that other stuff is, you can't do it with DJI RTK base station.