Evening
Jaba et al
One last one on this to ensure there is 100% factual clarity on this GPS availablity issue!
Please all, read them ... I mean, grab a cuppa and READ THEM IN FULL!
What we know so far:-
The system here and abroad will have:-
- Back-up ground based navaids
- PRIM and SSR around the capitals
- VHF and procedural sep options in the CTA GAFA and elsewhere
- TXPDR's that will (if like Microair's) be able to be selctable as A, C, S or ADS-B (redundant in other words if GPS is U/S)
All the above .... just in case GPS falls over ... no matter how unlikely!!
How unlikely? .... read on
2002 U.S. Global Positioning System and European Galileo System
U.S. Global Positioning System and European Galileo System
A nice PPT that puts much of today’s GPS and related (including Aviation) together
http://pnt.gov/public/2007/2007-09-I...idersforum.ppt
Current PNT state
National Executive Committee for Space-Based Positioning, Navigation, and Timing
US/International Co-operations
National Executive Committee for Space-Based Positioning, Navigation, and Timing
Current PNT Policy
U.S. Space-Based PNT Policy
And last but not least, a historical document suite that provides a background to the decisions that have led the GPS systems to where they are today.
RAND | Monograph/Reports | The Global Positioning System: Assessing National Policies
These links provide a clear (and verifiable) context to the significance with which the GPS systems are utilised across industries around the world, and therefore of such significance, that the number of agencies and governments (including DoD's internationally) have strict protocols, inclduing in the worst case scenario, ‘local’
contingencies in place, as the broad brush SA or OFF options are just not feasible anymore!!
…. That is off course unless something so substantial were to occur to warrant it …. When read in context with the safe guards in the PNT policies above, and the intergovernmental considerations within!
…. In such an event if the decision was sactioned and taken by multiple governments either locally or globally, the loss of civilian GPS is not likely to matter to many folks when in comparison to the event that would preceed taking such a decision IYKWIM 
Enjoy the reading …..
Bing 