> [...]and uses military-grade GPS to ferry it to a secure bay[...]
Something tells me Gatwick isn't actually in possession of the decryption key for the US Air Force's P (precise) signal and this is just some PR person taking it too far.
It's a myth that civilian GPS is less precise than military. A modern, dual-frequency or augmented civilian GPS receiver is just as precise as a military GPS.
P may have once stood for precise, but now days the main advantage of the encrypted, military P signal is that it prevents spoofing attacks.
It used to be true but in 2000 Selective Availability was disabled which made the civilian signal just as precise. This is basically why GPS took off around that time despite having been in operation for two decades at that point.
It's just one of many whys. Differential GPS was widely available and it gave cm-level positioning precision.
Equally if not more important why was your good old hardware minituarization and its cost reduction. In the late 90s a decent GPS reciever was still a size of thick book and cost prohibitively.
Again, coupled with differential corrections (available for free over radio) the resulting precision was in centimeter range. The reason it wasn't used was the physical size and cost (for hand-held navigation) and the lack of supporting hardware in cars (no user-facing on-board systems with screens and UI).
SA was _not_ the reason for the lack of consumer-level GPS adoption.
In my experience using DGPS around 2000, most of the DGPS sources were near the coasts and operated by the Coast Guard. There were a few scattered transmitters here and there, certainly not enough to provide the kind of coverage we now enjoy.
It's probably safe to conclude that they don't, but you don't need COMSEC crypto keys to achieve "military-grade" accuracy down to 10cm either, i.e. differential GPS[1].
Yea I was on a project where a professor lent us a Trimble GPS (I think they ran $2k ~ $4k at the time). It had a backpack, synced up with a tower at the local airport and gave us information down to a couple of centimeters.
Probably not, since the main benefits of the military signals are improved resistance to jamming/spoofing, and having a signal that can continue to work if the civilian signal is turned off. If you sell those keys to random businesses they become less effective
Something tells me Gatwick isn't actually in possession of the decryption key for the US Air Force's P (precise) signal and this is just some PR person taking it too far.