I just did a test on my cheapest (3 for $15-$20) GPS module... a V.KEL Sirf III receiver. Indoors, on the lower level floor, away from windows, etc. I was getting 25-35 dBc levels with the patch antenna properly oriented. With the module flipped over and the antenna surface on a hardwood floor (and the circuit board/GPS can pointing to the sky and shielding the antenna), signals were around 6 dBc lower. The receiver was even tracking sats that were below 12 dBc. GPS receivers have come a long way in the last few years...
I just did a test on my cheapest (3 for $15-$20) GPS module... a V.KEL Sirf III receiver. Indoors, on the lower level floor, away from windows, etc. I was getting 25-35 dBc levels with the patch antenna properly oriented. With the module flipped over and the antenna surface on a hardwood floor (and the circuit board/GPS can pointing to the sky and shielding the antenna), signals were around 6 dBc lower. The receiver was even tracking sats that were below 12 dBc. GPS receivers have come a long way in the last few years...
