GPS data for each frame
1978 3 2019-3-26
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sebko
lvl.2

Germany
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Hey, I am doing a software project for the university with the DJI Matrice 100. A part of the project is object tracking. For that, I am using GPS data and the camera. I noticed while analyzing the flight data that there isn't a GPS entry for every frame in the log file. So is the Matrice not able to log flight data for every frame? Has anyone experience with syncing flight data and the video output?
I wrote my own data logging app which only logs while filming, but it also logs way fewer data points then there are frames in the video.
2019-3-26
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Keule
Second Officer
Flight distance : 3733015 ft
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United Kingdom
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If you need GPS position data inflight then you should use the UART port on the M100.
The flight controller provides detailed real-time state information at up to 200 Hz for positioning, altitude and a few more parameters.

If you need GPS data for something after the flight, use the onboard .DAT logs to get higher resolution data.
The .txt logs provide only low resolution data, so there is a chance that your footage and GPS position do not exactly match for each frame.
2019-3-26
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sebko
lvl.2

Germany
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Keule Posted at 3-26 21:37
If you need GPS position data inflight then you should use the UART port on the M100.
The flight controller provides detailed real-time state information at up to 200 Hz for positioning, altitude and a few more parameters.

Thanks for the insight.
I am still a little confused. I am using my own logging function where my app calls the function getPosition from the flight controller. The function is called on every frame update, so I should get the same amount of data points as the number of frames in a video. But there are much fewer data points in the GPS log as there are frames in the video.
2019-3-27
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Keule
Second Officer
Flight distance : 3733015 ft
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United Kingdom
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If you are recording with 25 frames/sec then you are calling getPosition() every 25th of a second? (e.g. every frame)
Does the function return NULL or junk?
What's the latency of that function?
2019-3-27
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