Designations given to the various GPS satellite generations.

• Block I satellites - prototypes that began launching in 1978.
• Block II satellites - 24 satellites that made up the fully operational GPS constellation declared in 1995.
• Block IIR satellites - replenishment satellites.
• Block IIF satellites - the 'follow-on' group.

TOP 10

1. travel guides

2. satellite navigation

3. gps

4. directions

5. route planner

6. satnav

7. atlas

8. postcodes

9. gis

10. compass

sat nav systems travel guides route planners travel resources GPS