Hello,
These questions are related to M30T cameras and jpg files metadata.
Can you kindly clarify the following questions:
1. Default setting for Zoom camera is always 2x. Can it be set to start with 1x (not zoomed at all?)
2. When switching from Wide camera to Zoom camera it always starts with x5 zoom. Can it be defaulted to the lowest zoom level or no zoom at all?
3. When flying an M30T drone connected to D-RTK 2, what line of sight is more important: is it between Drone itself and D-RTK 2 station or is it between drone remote controller and D-RTK 2 station? Or should it be both?4. The metadata that drone recorded in jpg images consist of GPS values of Latitude, Longitude and Altitude. Images are taken simultaneously by Wide camera and Zoom camera of M30T. Zoom was at its default lowest value of x2. These cameras are located on the same gimbal and are very close to each other. For some reason, these two cameras recorded jpg files with a large difference in Altitude. For example Zoom camera jpg shows Altitude value of 78.239 but Wide camera jpg shows Altitude value of 18.992. Why is it happening? Which one is correct? I noticed that the drone was given a warning message that the satellite signal was weak. Is this a reason for such a large difference?
5. Image from Zoom camera, for parameter "Altitude Type" shows "GpsFusionAlt". Image from Wide camera, for parameter "Altitude Type" shows "RTKAlt". What does it mean?
6. EXIF metadata reporting "Absolute Altitude" and "Relative Altitude". What does it mean?
7. When Latitude, Longitude and Altitude are recorded what location is it defined? Is it the center of the camera lens? Is it the center of the drone? Is it the center of the image?
8. Can you please confirm that Altitude units reported in jpg images are in meters and it is reported Altitude is ASL (Above Sea Level)?
9. What does "Surveying mode"=0 versus "Surveying mode"=1 mean? One is reported in the image by Zoom camera and other from Wide camera

I appreciate any help you can provide.
Best regards

Hi, there.
Sorry for the late reply.
This link may help you solve your problems, please have a look: https://www.dji.com/matrice-30/downloads
We will also forward your problems to the relevant team to see if we can help you more.
Thank you.

Update: Please check the following details:

1. Default setting for Zoom camera is always 2x. It can normally not be set to start with 1x.
For 1x magnification, it is recommended to switch to a wide-angle lens.

2. When switching from Wide camera to Zoom camera it always starts with x5 zoom. It can not be defaulted to the lowest zoom level or no zoom. This is the default setting of the APP and cannot be modified

3. When the M30T is connected to the D-RTK2, the D-RTK2 communicates directly with the aircraft, so it is necessary to ensure that the communication between the UAV and the D-RTK2 is good (no blocking and no interference)

4.If the height difference between the wide-angle and zoom photos taken at the same time is large, it is recommended to provide the original photos for further confirmation

5. GpsFusionAlt" altitude calculated for the fusion of GPS and barometer, the altitude value will be affected by the ambient air pressure, and the error is relatively large. "RTKAlt" is the RTK positioning altitude, which is an absolute altitude, and the error is relatively small.

6. The absolute altitude can also be understood as the normal altitude, when RTK is positioned, the absolute altitude is obtained, and the relative altitude is the altitude of the aircraft relative to the take-off position.

7. M30T is not professional photogrammetry equipment, the defined position is not the center of the lens or image, when it is GPS positioning, it is the center of the aircraft, and when it is RTK positioning, it is the phase center of the RTK antenna

8. In the case of RTK positioning, the height in the photo is ASL, and the unit is m.

9. "Surveying mode"=0 (not recommended for surveying and mapping operations), "Surveying mode"=1 (the accuracy of this photo is guaranteed, it is recommended for surveying and mapping operations)

Natalia,
Thank you very much for your help!
Nilich

DJI Natalia Posted at 10-7 22:32
Update: Please check the following details:

1. Default setting for Zoom camera is always 2x. It can normally not be set to start with 1x.

Hi there,

"8. In the case of RTK positioning, the height in the photo is ASL, and the unit is m."

I cannot confirm that. Even though it's stated otherwise in EXIF data. For example:

GPSAltitudeRef - Above Sea Level
GPSAltitude - 719.42 m

I can confirm that the listed value is not ASL (Above Sea Level) but HAE (Height Above Ellipsoid). The HAE at my location is always about 45m highter than ASL hight. This is very confusing since every other altitude is ASL (drone altitude, laser range finder, etc). It would be great if this could be fixed

rmuc_ Posted at 10-27 07:29
Hi there,

"8. In the case of RTK positioning, the height in the photo is ASL, and the unit is m."

Hi, there.
We will confirm this problem with the relevant team and keep you updated here asap.
Please don't worry.
Thank you for your patience as well.

rmuc_ Posted at 10-27 07:29
Hi there,

"8. In the case of RTK positioning, the height in the photo is ASL, and the unit is m."

Update:
Sorry for the late reply.
Please note that the height recorded in the EXIF information of the photo is ellipsoid height, non-ASL altitude.
Thank you.

So the "GPSAltitudeRef - Above Sea Level" tag is incorrect? I've wondered about this with other DJI RTK-equipped aircraft...

I don't think you can.

DJI Natalia Posted at 2022-10-7 22:32
Update: Please check the following details:

7. M30T is not professional photogrammetry equipment, the defined position is not the center of the lens or image, when it is GPS positioning, it is the center of the aircraft, and when it is RTK positioning, it is the phase center of the RTK antenna

In reference to number 7.. Can you provide the location of the RTK phase center and/or an offset for M30T RTK antenna phase center to center of sensor for post processing similar to the information provided in this article for the M300?
https://forum.dji.com/thread-276512-1-1.html