Time resolution in log file

ArduCopter
1

Hi,

I am trying to understand what is the best timing resolution of GPS logs I can get. Currently it seems it is 100msec.

GPS time is recorded in my logs in a granularity of 100 msec since 6Jan1980 and I read it in the CAM event

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I need to know the CAM event on a finer resolution.

Is it possible to get this tag at a finer resolution? At what frequency does the navigation module or EKF is working at? Even if the GPS is updating at 1,5,10 Hz, navigation solution can happen faster and then the log can be maybe tens of msec (maybe faster?).

Is it possible to control this resolution in MP?

Tnx !

2

No, it is not possible without changing the source code.
Each message is logged at different frequencies, there is no such thing as a single global logging frequency.

3

Tnx @amilcarlucas Is it possible to control the CAM/TRIG tag frequencies then?

4

Search this forum, I’m sure there is some info about that here.

5

Tnx @amilcarlucas. I actually did not find anything relevant.

i did find relevant discussions here https://github.com/ArduPilot/ardupilot/issues/2289 noting it may be possible to get down to 20msec but I am still not clear exactly on how to do it.

I am running Copter 3.5.5 and I get 100msec consistent granularity between TRIG and CAM which is not accurate enough in my case. I configured according to https://ardupilot.org/copter/docs/common-camera-shutter-with-servo.html#enhanced-camera-trigger-logging (Enhanced camera trigger)

Would appreciate any pointers in the matter.
Tnx!

6

Save the parameters so that you can downgrade later… and update to 4.0.4 to re-test. If it works worse, downgrade and re-load the parameters that you saved before.

7

so far 4.0.4 did not yield any difference.

Very fruitful discussion here for anyone interested. I was not able to get better logging resolution however. Seems using the TimeUS logged at usec resolution can be used to interpolate the CAM time better than the log.