Highest altitude GPS fix
Who
MMS Navigator GPS Receiver
What
70,135 kilometre(s)
Where
United States (Greenbelt)
When

The highest altitude GPS fix is 70,135 km above Earth, detected aboard NASA's (USA) spacecraft MMS Navigator, and relayed to Goddard Space Flight Center, Greenbelt, Maryland, USA, on 19 March 2015.

The GPS signals were captured by a NASA's own GPS receiver, named Navigator.