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? Are there any "configurations" that
might not pose a problem? (i.e. 2 furthest sides only, half of bottom
only, etc).

I am adding in the sci.geo.satellite-nav newsgroup, as people there
are familiar with GPS antenna issues, and could explain this better
than I can.

First, you need to know what style of antenna your GPS has. Most are
either a patch antenna (the Garmin eTrex series) or a quad helix
antenna (some Garmin and most Magellan). The positioning and shielding
issues are rather different for the two.

You are right to be concerned about reflected signals, or multi-path,
issues. That can degrade accuracy.

Also consider a GPS model with provision for an external antenna,
which might give you more mounting options. You could have a
completely shielded box, with a passthrough for the GPS antenna cable,
to the antenna mounted completely outside the shielding.

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom