*ahem* I think you should have been referring to _GPR_ if you thought about radar; GPS is the positioning system, which is something entirely different. (Not that you can't use it as a complement, but it's not a radar device. Radio, yes. Radar, no.)
Very few GPR systems can be used from a distance. (My father has made antennas that can detect the snow thickness from a low height, but it would probably be very different for rocks, and you wouldn't want to fly directly above a volcano, anyway.)
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timeasmymeasure
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Date: 2004-10-07 06:43 am (UTC)Very few GPR systems can be used from a distance. (My father has made antennas that can detect the snow thickness from a low height, but it would probably be very different for rocks, and you wouldn't want to fly directly above a volcano, anyway.)