> For the complete documentation index, see [llms.txt](https://support.onegiantleap.co.nz/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://support.onegiantleap.co.nz/legacy-features/gps-sync-box.md).

# GPS Sync Box

## For what length of time will the sync remain valid?

Located inside every power meter is a Real Time Clock (RTC) which accurately keeps tracks of Coordinated Universal Time (UTC) since the last sync took place with a GPS Sync Box.

The RTC is accurate to ±0.432 Second/Day over the entire temperature range from -45°C to +85°C. In other words, the RTC will drift no more than ±0.432 over the course of 24 hours, even if the temperature varies significantly throughout the day.

We have defined it such that a sync will be considered expired if 6 hours or more have elapsed since that sync occurred. This equates to a worse case drift of ±0.108 seconds which closely lines up with the 100Hz High Speed Data sampling period of 0.100 seconds.

## How often will the power meter search for a sync?

Searching for an active GPS Sync Box consumes power, so we want to limit the time the power meter spends searching for one.\
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If the power doesn't currently have a valid sync, then it will start search more frequently - more specifically, the power meter will begin a short search (for 5 seconds) every 60 seconds.