Abstract: A GPS system (12) including an antenna (12), a GPS receiver (14), and a baseband subsystem (16) is disclosed. The receiver (14) includes a reference clock (20), a down converter (22), and a baseband detector (24). The baseband detector (24) is coupled with the output of the down converter (22) and includes a numerically controlled oscillator (30), an adder circuit (32), a code generator (34), a code mixer (36), and a carrier mixer (38). The adder (32) corrects errors caused by clock errors generated by the receiver's reference clock (20) as they occur by adding a clock correction frequency to the oscillator (30) signals.

Abstract: A method and apparatus for automatically adjusting the bandwidth of a GPS receiver's phase lock loop in response to acceleration changes of the tracked vehicle. The bandwidth is increased when the vehicle's acceleration rate exceeds a pre-determined value for maintaining phase lock loop and is reduced when the vehicle's acceleration rate drops below a pre-determined value for reducing the amount of noise introduced into the phase lock loop.