If you look at the datasheet for any of ublox’s current GPS chips, you’ll see that they’re supposed to be able to keep tracking GPS satellites down to -167 dBm. That is a terrifyingly small amount of power, and probably the smallest number that I’ve ever actually seen in real life. To make sense of this, you need to know what a dBm is — it’s a decibel relative to 1 milliwatt. Decibels are logarithmic, so every time you add or subtract 10 dB the power gets multiplied or divided by ...
