Data logging for geotagging photos

I’ve purchased a base and rover module (TinyRTK), and I was hoping to used these modules ultimately to geotag images from a camera. I see a few options:

  1. Use my Pixhawk to record the GPS positional data from the RTK, and record camera trigger events somehow with an accurate timestamp from the TinyRTK.

  2. Do the same as above, but use a Raspberry Pi.

  3. Use the TinyRTK only, and send positional data back to the ground station in telemetry.

Can these be done with the TinyRTK, and if so, could someone please point me to a guide?

I think I may have gotten the wrong modules for my application. The rover could be any camera help in hand by a person or on a drone.


I do not think that the Tiny RTK can be useful for geotagging.

What do you mean by "accurate " ?
As far as I know with the Pixhawk. method 1, you will always have at least 200ms error .

Do not think that method 2 or 3 will make things better or work better.

Why the 200 ms delay?

A few answers to your questions :

  1. You can use your Pixhawk to record camera trigger events indeed, if you use the hot shoe method (Enhanced camera trigger logging), you can get pretty accurate timestamps. The timestamp will be generated by Pixhawk, but Pixhawk syncs itself with GPS at startup, so it is pretty much the same.

  2. It is possible, max. RTK rate is 8Hz, so you can use a GPIO input to detect camera shutter and then interpolate position depending on previous and next positions. There is also a possibility to generate the timestapm on TinyRTK directly by using the EXTINT pin.

  3. Also possible, the timestamp can be generated with the EXTINT pin and then a little post-procesing will be needed to calculate the position due to the 8 HZ rate limit.

Thanks Kevin. I’m interested in using the EXTINT pin. Can you point me to some documentation on how to hook it up and use it? Thanks.


You have to enable the UBX-TIM-TM2 message, then a rising or falling edge on EXTINT pin will output one of those messages. The messages contains a counter, timestamps, estimators, etc…