Powering UP/DOWN a GNSS Receiver
When power is first applied to a GNSS receiver, it begins looking for satellites. It does this by searching for each satellite, individually, listening for every satellite's distinct spread-spectrum hopping sequence. This process can take several minutes, as the receiver iteratively locates satellites, refines its position, and determines for which satellites to search.
When the power is switched off, a GNSS receiver retains the last known position. This typically results in faster satellite acquisition the next time it is switched on, because the receiver will use the previously mentioned Almanac data to locate the satellites. If, however, the antenna has been moved more than a few miles, or too many days have passed since the power had been turned off, acquisition time will be longer.