🚀 go-pugleaf

henry@zoo.toronto.edu (Henry Spencer) writes:
: The noise being injected by DoD (the buzzphrase is selective availability)
: is currently of a relatively simple type that can indeed be removed by
: long-term averaging.

I have a few of questions. Suppose we end up with a president who places
a higher priority on commerce rather than restricting the military buildup
of countries like Iraq, and accurate navigation information is declassified.

  1. Can the "noise" be turned off, or do we need new satellites?
     (With DoD involved, this isn't a stupid question.)
  2. I thought selective availability mean't that noise was injected only
     during a military operation, e.g. the Gulf War. However, it wasn't
     enabled then due to a shortage of military units and many commercial
     receivers were used. Why do I read that commercial units still don't
     have the accuracy that military units have, i.e. how is full precision
     information transmitted?
  3. Would special or extra hardware be required to receive full precision
     information over existing receivers?
  4. Is differential GPS used just to overcome the selective availability
     noise, or are there other sources of error?
  5. What is the precision of commercial vs military GPS with/without
     SA enabled?