Re: GPS

Thomas Barclay schrieb:
> 
> 2) Can differential GPS (multi-receiver) defeat or 
> significantly attenuate the futzing up signal? 
> (That is, can't differential GPS be used in such a 
> way as to amerliorate the effects of signal 
> uncertainty introduction)? If so, the only 
> receivers that will be seriously futzed by the 
> fuzz that can be inserted (fuzz substituting for 
> any real technical understanding....) would be 
> the non-differential single receiver GPSes, 
> correct? (And yes, these are the more common 
> variety IIRC)

I am not sure about differential GPS being used to correct distorted
signals. My guess is that it's possible.

The differential GPS schemes I am aware of all require a fixed
reference point or terrestrial GPS sender of known location. This
implies limited range (covering say, a city, port or airport). Thus it
is not too relevant for military operations, though it could be useful
in street fighting. Taking out differential GPS antennas might be as
relevant an aim as other communication devices.

> 3. If the US (or anyone) were to fuzz up a 
> signal coming from someplace and this caused 
> some manner of disaster (air crash, ship to run 
> aground and sink, etc), wouldn't that be a very 
> bad thing? (Yes, I know secondary navigation 
> methods are meant to verify positions, but 
> people ARE becoming GPS dependent).  I 
> realize when weighed against a large scale 
> offensive, these risks are minimal, however I can 
> see someone attempting some form of 
> litigation... (Land of the Free, Home of the 
> Lawyer)

Interesting thought. Certainly the GPS distortion cannot be aimed to be
limited to, say, Iraq. Other countries in the area might be affected
(including allies such as Israel or Turkey), as well as international
air traffic in the region. Air traffic disruption (even without
accidents) might be enough to have the airlines calling for help from
the government.

Greetings
Karl Heinz