Patent ID: 7155183

Claim:
Within a mobile device comprising cell phone circuitry and GPS circuitry, a method for producing a reference signal for a GPS receiver comprising: producing a cellular oscillator signal and a frequency error signal within the cell phone circuitry, where the frequency error signal is for controlling an oscillator to operate the cell phone circuitry within cell phone network specifications; coupling the oscillator signal to at least one numerically controlled oscillator within GPS circuitry; processing the frequency error signal to produce a frequency control value that is coupled to the at least one numerically controlled oscillator; generating, within the at least one numerically controlled oscillator, a signal in response to the cellular oscillator signal and the frequency control value that is used for processing GPS satellite signals; searching for a pilot tone or a carrier signal of a cellular telephone by tuning a frequency of an oscillatory signal generator; fixing the frequency of the oscillatory signal generator when the pilot tone or the carrier signal are not found; searching for the GPS satellite signals; and returning to searching for a pilot tone or a carrier signal when the GPS satellite signals are not found.