After years of delays, only one GPS III satellite has launched so far. To complete the “A block” of the constellation, nine more are scheduled to launch by 2023. hide ...

Until now, however, the minimum number of GPS satellites needed to determine the exact position of a mobile phone or other navigation device has remained a matter of conjecture.

Here, UNSW academics Professor Andrew Dempster and Dr. Craig Roberts give a sneak peek what people can expect from GPS over the next 50 years.

Tuning into a GPS satellite is nothing new. Your phone and your car probably do that multiple times a day. But [dereksgc] has been listening to GPS voice traffic. The traffic originates from COSPAS… ...