In message <20060706174621.GC16406_at_ccil.org>, John Cowan writes:
>Rob Seaman scripsit:
>
>> Most troubling would be if two moving platforms are depending on GPS
>> units with differing delays, e.g., two airplanes following neighboring
>> flight paths. How far does an airplane move in 2 seconds? What is
>> the minimum separation required by the FAA?
>
>Jetliners travel at about 550 mi/hr, or 246 m/s. Required horizontal
>separation depends on circumstances, but is rarely less than 3 miles =
>4828 m. So if the discrepancy is 2 s, there is a safety factor of
>about an order of magnitude. Good enough.
The ban on hand-held GPS for primary means of navigation is partly
because of the worries about the slowness of updates.
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Received on Thu Jul 06 2006 - 11:43:49 PDT