Gary S. wrote:
On 30 Jun 2004 13:00:23 -0700, (David Harper)
wrote:
I was wondering what effect aluminum foil (used as a radiation heat
shield) would have on GPS signal reception? The scenario is a small
payload container (approx 10" cube) covered in polystyrene, with a
handheld GPS reciever located near the top on one corner.
Would aluminum foil on the inner sides (and/or bottom) interfere with
the reception of the signal? I'm worried about possible reflection or
other mechanisms of interference that might occur and prevent good
reception. Basically, my question is, would foil on the sides or the
bottom pose a reception problem?
I'd expect this to be alright as long as the GPS antenna still has a
clear view of most of the sky - i.e. if you imagine your eye being at
the location of the antenna, it should be able to directly see most of
the sky without needing to look through any aluminum foil. Multipath
problems from reflections tend to be more of an issue when the direct
path is blocked so the receiver only gets the reflected signal and when
the path length of the reflected signal is substantially different than
it would be for the direct signal. Neither would be the case here.
There could still be some destructive interference from reflected
signals but that problem is minimized if the direct signal path is
unobstructed and therefore the strongest signal and by the selective
antenna gain for signals of the proper circular polarization.