RTK for M3T

[JCDiaz]

I have heard about the RTK technology to help with eventual interference while inspecting power lines, cell towers and even methalic structures.

Like to hear your opinions about this. I will receive my M3T in a couple of days.

Regards
Juan

 

[Found By Drone]

It won't work for that purpose because it is only 'single (puck) RTK'.

You need 'dual RTK' like what's on the Matrice 30 series in order to gain the benefit of using RTK to resolve environments with strong EMF interference. If you look at the M30/M30T you'll see it has two pucks, one on each rear leg. It has to have two RTK modules with some separation in order to effectively calculate a heading. The aircraft knows the precise location of each puck, so it can use that info to determine it's orientation in real-time, in the event the aircraft's onboard magnetic compass is unable to detect heading due to strong environmental electromagnetic interference.

That said, the Mavic 3 Enterprise series (M3E/M3T) RTK module provides improved positional accuracy only. This is great for survey work, mapping, maintaining positional stability in operating in elevated wind conditions, and my favorite... perfect automated landings every time! With RTK your aircraft will land on a dime - everytime!

 

[jaja6009]

It won't work for that purpose because it is only 'single (puck) RTK'.

You need 'dual RTK' like what's on the Matrice 30 series in order to gain the benefit of using RTK to resolve environments with strong EMF interference. If you look at the M30/M30T you'll see it has two pucks, one on each rear leg. It has to have two RTK modules with some separation in order to effectively calculate a heading. The aircraft knows the precise location of each puck, so it can use that info to determine it's orientation in real-time, in the event the aircraft's onboard magnetic compass is unable to detect heading due to strong environmental electromagnetic interference.

That said, the Mavic 3 Enterprise series (M3E/M3T) RTK module provides improved positional accuracy only. This is great for survey work, mapping, maintaining positional stability in operating in elevated wind conditions, and my favorite... perfect automated landings every time! With RTK your aircraft will land on a dime - everytime!

Actually the RTK is not great on the M3T for survey or mapping. The Mavic 3T does not have Time Sync, which is needed to get the precise coordinates and elevation written to each image. When mapping with it, you will get images with accuracy values in Pix4D or Metashape, but they will not be centimeter accurate.

The Mavic 3E and Mavic 3M both have Time Sync and therefore can create accurate maps and models.

You can always use ground control points if you needed centimeter accurate maps with the Mavic 3T.

For the Mavic 3T, the RTK module is for accurate positioning only. I use the similar RTK module on my Mavic 2 Enterprise Advanced and I use it to run precise repeatable inspections with images and videos. It works great when overlaying and comparing videos and images.

 

[AstroNoot]

Actually the RTK is not great on the M3T for survey or mapping. The Mavic 3T does not have Time Sync, which is needed to get the precise coordinates and elevation written to each image. When mapping with it, you will get images with accuracy values in Pix4D or Metashape, but they will not be centimeter accurate.

The Mavic 3E and Mavic 3M both have Time Sync and therefore can create accurate maps and models.

You can always use ground control points if you needed centimeter accurate maps with the Mavic 3T.

For the Mavic 3T, the RTK module is for accurate positioning only. I use the similar RTK module on my Mavic 2 Enterprise Advanced and I use it to run precise repeatable inspections with images and videos. It works great when overlaying and comparing videos and images.

Mavic 3T owner here. I'm using DJI Terra and pictures have slightly varrying positional accuracy, but the average is around 2cm horizontal and 4cm vertical.

Also in the DJI PSDK, there's mention of the Mavic 3E/T (no M) in their Time Synchronization feature table. Payload SDK

 

[jaja6009]

Since you have a M3T and Terra, make a map and use Check Points and post the results.
While I do not own a M3T, it has been reported by others that when making a map and checking with check points, people are not seeing centimeter accuracy. DJI states on the FAQ that that sUAS is not for precision mapping.

With the Mavic 2 Enterprise Advanced with RTK module I get the same image accuracies when importing into photogrammetry software.



When I process the map and check with check points gathered with a multi-constellation, multi frequency Rover the RMSE is in feet.



FAQ on Mavic 3 Enterprise




FAQ on Mavic 3 Multi Spectral.


There are tests showing the Mavic 3 Multispectral has low centi-meter accuracy mapping using just the RTK module and no GCPs.


From the PSDK

Also the M30 and M30T may have RTK, but it is for positioning only. There is no Time Sync for precision mapping.
The Matrice 300 RTK when using the H20(T) is also for positioning only and is not for precision mapping. When using the P1 and L1 payloads though, Time Sync is enabled and therefore support is there for precision mapping.

 

[AMann]

It won't work for that purpose because it is only 'single (puck) RTK'.

You need 'dual RTK' like what's on the Matrice 30 series in order to gain the benefit of using RTK to resolve environments with strong EMF interference. If you look at the M30/M30T you'll see it has two pucks, one on each rear leg. It has to have two RTK modules with some separation in order to effectively calculate a heading. The aircraft knows the precise location of each puck, so it can use that info to determine it's orientation in real-time, in the event the aircraft's onboard magnetic compass is unable to detect heading due to strong environmental electromagnetic interference.

That said, the Mavic 3 Enterprise series (M3E/M3T) RTK module provides improved positional accuracy only. This is great for survey work, mapping, maintaining positional stability in operating in elevated wind conditions, and my favorite... perfect automated landings every time! With RTK your aircraft will land on a dime - everytime!

Doesn’t the M3E RTK use a stationary base station for more accuracy? I don’t understand how having two RTK modules on the moving aircraft would allow for RTK to work- what I understand of it (and use with my two RTK survey units) is that it uses a stationary base (ground station) for reference and the rover (the drone).

I understand that the Matrice 30 dual antenna system allows for redundancy and better signal reception, however, as it says in the features list “the dual antennas are mutually redundant, and both can be used as antennas for RTK positioning system and GNSS Modules.” This doesn’t imply it’s a standalone RTK system when using just the drone, you will still need reference data from a separate base station to get true RTK accuracy.

 

[Found By Drone]

Doesn’t the M3E RTK use a stationary base station for more accuracy? I don’t understand how having two RTK modules on the moving aircraft would allow for RTK to work- what I understand of it (and use with my two RTK survey units) is that it uses a stationary base (ground station) for reference and the rover (the drone).

I understand that the Matrice 30 dual antenna system allows for redundancy and better signal reception, however, as it says in the features list “the dual antennas are mutually redundant, and both can be used as antennas for RTK positioning system and GNSS Modules.” This doesn’t imply it’s a standalone RTK system when using just the drone, you will still need reference data from a separate base station to get true RTK accuracy.

Yes, any of the drones (M3E/M3T/M30/M30T/M300/M350) still require real-time correctional reference data from an NTRIP provider in order to have RTK functionality. Dual RTK does not replace this. Dual RTK still uses correctional data, but instead of having one corrected location, it now has two. And with two geospatial data points, separated by even a small distance, the aircraft can extrapolate heading. A single puck RTK drone (M3E/M3T) cannot do this.

 

[AMann]

Yes, any of the drones (M3E/M3T/M30/M30T/M300/M350) still require real-time correctional reference data from an NTRIP provider in order to have RTK functionality. Dual RTK does not replace this. Dual RTK still uses correctional data, but instead of having one corrected location, it now has two. And with two geospatial data points, separated by even a small distance, the aircraft can extrapolate heading. A single puck RTK drone (M3E/M3T) cannot do this.

That’s pretty cool, as having a way to precisely set a heading would make image edges parallel to each other and there would be less off line drifting? Thanks for explaining it, I didn’t know they had this.