Gsm cellular telephone and gps receiver combination

Abstract

A GPS/GSM receiver combination for receiving GSM and GPS signals using an RF GPS integrated circuit for downconverting the GPS signal. The GPS integrated circuit includes a synthesizer for generating LO signals, first and second downconverters for using the LO signals for downconverting the GPS signal, and a sampler for providing in-phase and quadrature phase sampled output signals representative of the GPS signal. The synthesizer includes a multi-mode divider for providing substantially the same first LO frequency at about the midpoint of the L1 and L2 GPS frequencies when either of a standard GSM reference frequency or historically common GPS reference frequency is selected. A standby mode in the integrated circuit is controlled by a power logic circuit using a power supply input as a logic control signal. The GSM/GPS receiver combination includes a GSM reference oscillator and a microprocessor system including a GSM frequency correction code for correcting the GSM reference frequency based upon a frequency correction beacon (FCB) signal received in the GSM signal. The GSM-based correction is then used for correcting the GSM reference frequency in order to center a frequency search for acquiring the GPS signal.