Spike Jones (
Mon, 14 Dec 1998 22:19:08 -0800

> Spike Jones [] wrote:
> >yes. this is a major shortcoming of gps guided exoatmospheric
> >devices. at typical reentry velocities you have only a very few
> >(typically 3) seconds to reacquire gps and react.

> wrote:
> Why would this be a problem? At least for the shuttle and other shallow
> reentry vehicles the shielding only occurs below it; the shuttle is now
> in continuous contact with the ground via the TDRS sattelites using the
> upper antennae. I guess that a much steeper re-entry might block out
> signals from above as well.

yes it does.

> Of course the fundamental flaw of all GPS-guided weaponry is GPS-faking
> or GPS-jamming. Relying on external signals to tell you your position is
> always risky.

right but as it turns out, the problem is daunting even with a fully cooperative
target. {8^D against a target that is technologically advanced and does not want to be hit, forget it. this might be exactly why the gps guided reentry bodies are not classified: they are not really practical. spike