[time-nuts] Thunderbolt GPS rollover

[Tom Van Baak]

> Keep in mind that a vast majority of these devices are used in "unmanned"  
> installations, i.e., cellular base stations, etc.

> Another factor, competition is so tough these days that most receiver
> chip manufacturers have dropped the eeprom for cost savings. 
> Doug

The trend these days for commodity GPS chips is "assisted GPS". Mobile phones and cellular base stations both have low latency access to the entire telecom infrastructure. When you can get the time of day, day of year, approximate lat/lon or up-to-the-minute GPS ephemeris, or leap second schedules over the net within milliseconds there is no longer a compelling need for something old-fashion like EEPROM or waiting 12.5 minutes to get orbit or UTC information at 50 baud from the satellites themselves. You could call it cost savings but really it's just a clever way to vastly improve specs like time-to-first-fix for a huge segment of the GPS receiver market. For example, why would a GPS chip in a smartphone need its own eeprom?

/tvb