why did old (like 90s/2000s) GPS take up to 15 minutes to get a lock, in giant bulky units, but my running watch gets it in 15 seconds?

Question

why did old (like 90s/2000s) GPS take up to 15 minutes to get a lock, in giant bulky units, but my running watch gets it in 15 seconds?

In: 3751

Answer 1

In the 90s the GPS signal was degraded to keep our enemies from using the GPS system.

>[On May 2, 2000 “Selective Availability” was discontinued as a result of the 1996 executive order, allowing civilian users to receive a non-degraded signal globally.](https://en.wikipedia.org/wiki/Global_Positioning_System#Timeline_and_modernization)

After 2000 the signal was no longer garbled. We went form seeing yourself within about 20 meters, to seeing yourself within about 15 centimeters.