1. A method for synchronizing to first and second signals from different respective signal sources in a positioning system, the method comprising: determining respective first correlation values at a plurality of time offsets for the first signal; determining respective second correlation values at the plurality of time offsets for the second signal, wherein the first and second correlation values are both determined using a common set of predicted data bits in a positioning system data frame; time aligning the first and second signals; combining the determined first and second correlation values at the plurality of time offsets after time alignment; and identifying a peak combined correlation value at one of the plurality of time offsets.