Automatic gain control in system simultaneously receiving GPS and GLONASS signals

1. A method of providing automatic gain control (AGC) for a receiver configured to receive both GPS signals and GLONASS signals, the method comprising:

initializing GPS-specific amplifiers, GLONASS-specific amplifiers, and any shared GPS/GLONASS amplifiers;

correcting a gain of the GPS-specific amplifiers and any shared GPS/GLONASS amplifiers using outputs of a GPS digital front end; and

following a GPS AGC lock, correcting a gain of the GLONASS-specific amplifiers using outputs of a GLONASS digital front end.

2. A method of operating a receiver configured to receive GPS signals and GLONASS signals, the method comprising:

providing automatic gain correction (AGC) to amplifiers in an analog front end (AFE) of the receiver, the providing AGC including:

initializing GPS-specific amplifiers, GLONASS-specific amplifiers, and shared GPS/GLONASS amplifiers;

correcting a gain of GPS-specific amplifiers and a shared GPS/GLONASS amplifier using outputs of a GPS digital front end (DFE) of the receiver; and

following a GPS AGC lock, correcting a gain of GLONASS-specific amplifiers using outputs of a GLONASS DFE of the receiver.

3. The method of claim 2 , wherein correcting the gain of GPS-specific amplifiers and shared GPS/GLONASS amplifiers as well as correcting the gain of GLONASS-specific amplifiers is performed by an interface counter device (ICD).

4. The method of claim 3 , wherein the outputs of the GPS DFE and the GLONASS DFE are quantized outputs in which only magnitude bits are counted.

5. The method of claim 4 , further including debugging the ICD by measuring other quantized outputs in the receiver.