>I just wanted to point out that GPS logging is entirely passive This is not entirely true, for example: http://en.wikipedia.org/wiki/Radar_detector_detector h

>I just wanted to point out that GPS logging is entirely passive This is not entirely true, for example: http://en.wikipedia.org/wiki/Radar_detector_detector http://en.wikipedia.org/wiki/Radar_detector_detector It appears that many, if not all GPS devices use superheterodyne receiver as well.