question about GPS power level in earth surface

[ongga]

hi i am ongga, my gps have received NMEA
$GPGSV,3,1,12,14,48,076,38,30,38,343,31,31,12,017, 29,06,64,170,39*71
the article say that SNR is in the seven point, that means SNR = 38
what is the meaning of 38? 38 dB or dBm?
and what is the power level gps in the earth surface??
thank's

 

[mbavaro77]

The unit is dB-Hz.

It is a pretty long story.. please google for example
GPS_Compendium(GPS-X-02007).pdf