The standard firmware has added support for gathering accurate timing information from a GPS unit, and there are some demos of this method's accuracy. However, the Audiomoth-GPS-Sync tool does not support synchronizing files recorded with the standard firmware. Looking at the metadata file recorded by the GPS, its not clear exactly how this information should be used to post-process audio files for the highest possible accuracy of time synchronization. Are there any scripts available for this? Or, could someone describe how to use the metadata so that I can implement a script?
Thanks!
I'm hoping to use the JS tools programmatically, outside of the GUI, but having some trouble. Posted an issue with details https://github.com/OpenAcousticDevices/AudioMoth-Utils/issues/1
Aha, I figured I was just missing it somewhere. Thanks!
Hi Sam,
The synchronisation tool for the standard firmware is in the Config App under the 'Process' menu option.
The code that this tool uses is in the AudioMoth-Utils repository - https://github.com/OpenAcousticDevices/AudioMoth-UtilsĀ - as aligner.js. If you configure the AudioMoth to make to make 59-minute recordings with 1-minute sleep intervals, the AudioMoth will make a fix before and after each recording, and then the Config App tool will adjust for start time drift and sample rate drift.
It is typically +/- 1ms compared to +/- 1us for the AudioMoth-GPS-Sync firmware.
The effect of correcting for the clock drift and sample rate drift are described in this application note:
https://github.com/OpenAcousticDevices/Application-Notes/blob/master/Using_the_AudioMoth_GPS_Board_and_Hat/Using_the_AudioMoth_GPS_Board_and_Hat.pdf
The Config App basically automates this process by reading the GPS.TXT file and applying the two corrections - LFXO and HFXO. Let us know if you have any problems.
Alex