[time-nuts] GPS "tests" by the DoD

Chris Albertson albertson.chris at gmail.com
Fri Jan 21 01:59:37 UTC 2011

On Thu, Jan 20, 2011 at 5:25 PM,  <lists at lazygranch.com> wrote:

> Another time I was driving I-5 near Lemoore Navy airstation and got a different type of jamming. The whole gps display rotate back and forth. No idea how that jamming was done.

Not just with GPS but in general that is the more sophisticated and
useful method of jamming.  Think of an airplane being targeted by an
radar guided missile.  It could simply broadcast while noise but then
it would become a very bright target to a radio homing missile.  And
you can bet $$$ that all radar guided missiles have a radio homing
mode build into their software.    The smarter jammer sends a faulse
signal back that is only "off" enough to cause the missile to miss but
not "off" enough that the missile can know it is being jammed.

A smart GPS jammer would slowly "move" the location reported by any
GPS receiver in the area just enough that weapons would miss their

Your civilian GPS can't really know if it is hearing a satellite or a
nearby 1.5GHz transmitter and will just take the stronger signal

The military GPS units are much harder to jam because they listen to
an encrypted signal.  So a military jammer either has to have the
right key (very unlikely) or just blast out white noise and make
himself a very bright target for radio homing missiles.

Jamming is a very sophisticated science because for every trick there
is are counter measures and so on for several layers

Chris Albertson
Redondo Beach, California

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