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The GPS owners (US DOD) have the prerogative to turn it off, or at least impair its resolution significantly. without a lot of warning. So a backup system is n
by OliverJones 11y ago
The GPS owners (US DOD) have the prerogative to turn it off, or at least impair its resolution significantly. without a lot of warning. So a backup system is necessary. But, it sounds like the engineer's knowledge of the route is that backup.
- jonknee 11y agoIf GPS gets shut off there will be such disruption that we can just stop all the trains.
- AnimalMuppet 11y agoWhen do they shut off (actually go to lower resolution) the GPS? When there's a war (invasion of Iraq, for example). Or when there's a bottleneck for two long in the process of launching replacement GPS satellites. You want to stop all the trains if one of those occurs? Until the military action is over or there's a successful satellite launch? Get outta here.
- jhayward 11y agoYour larger point about backup being required is very salient, however it is no longer the case that GPS can be turned off or impaired by DOD. When SA was turned off in 2000 it was irrevocable. GPS satellites designed since that date do not carry the SA feature capability.