Originally Posted by RaymondR
I seem to recall
that the old "transit" satnav was emplaced by the US navy
to allow missile submarines to come up to periscope depth
during the hours of darkness to check on their inertial navigation derived position.
The first time I observed one being used to locate an offshore oil
exploration well it required half a helicopter load of electronics and sat taking positions for about two days whilst regularly printing out a scatter plot with a fairly noisy dot matrix printer. After about two days it was assumed that the correct position was one in the middle of the scatter plot.
Now they are in mobile phones and tablets and accurate within a few metres, the wonders of modern technology.
Ok so your all slightly up the wrong tree GPS
is easy to spoof military or not they use the same system and freq ranges (mil gps looks at 2 component's in the data) the mil component has a key on it that makes it a lot harder to spoof. Both work
on time and both are very weak signals so yes your domestic jamer / spoofer is short range but put that on any decent transmiter and boom. Same for jamming both are affected and its easy to overpower. However unless you are a target you are not likley to see it, governments are very careful to not effect civilians and watch closly any one playing with this at a state level. Second all military establishments are going back to training
with satilite free sytems for crucial tasks, for a good reason, should a major conflict evolve access to any satilite systems are not guaranteed with most major states possesing anti satalite technology, and in this case the gps systems would be first down, more because of the effects on economys and telecommunications than location. I think your mad to navigate on gps alone but i know some do.