Fig. 3

Achieved time accuracies with optimised methods for automatic time synchronisation on bio-loggers in stationary experiments (GPS [A], WiFi and NTP [B], wireless proximity messages [C-D]). The achieved accuracies with WiFi (B) are separated by the internet speed (broadband, mobile LTE, mobile 2G). During the 16-day-long relative time synchronisation experiment between two tags (one positioned outside, the other inside), an automatic resynchronisation was triggered because the tags measured a relative time difference of more than 50 ms onboard (D). The tag temperatures were measured with an onboard temperature sensor (Bosch Sensortec BME680)