In article , Dave Holford
wrote:

Harry Andreas wrote:

In article , Michael Williamson
wrote:

Cub Driver wrote:

as long as the GPS is working. But it's a low-powered signal from orbit
and it's easily jammed.


How true is this, really? In an aircraft, you are between the ground
and the satellite. How does someone on the ground interfere with the
signal?


I don't believe that the antenna for the GPS is directional enough
that someone off axis couldn't put a signal into your system- after
all, a single antenna is used to pick up every satellite above the
horizon.

Wrong on both counts.
Most airborne GPS systems have multiple antennas and can be
made directional.
Not sure how much I can say in this forum until I check security.

--
Harry Andreas
Engineering raconteur


Must be quite complex to track multiple moving satellites scattered
around the sky from a moving platform with limited antenna real-estate.

That's why we have the contract instead of some commercial firm.


From what I understand, from publicly available literature, multiple
balloon mounted jammers could pose a real, and relatively economical,
problem.

Not unsolvable. Just a bit more hardware and some money.

--
Harry Andreas
Engineering raconteur