System and Method for Using CDMA PN Offset to Maintain Instrument Timing Reference

A system and method is provided enabling identification of different PN offsets values for CDMA signals without access to a GPS signal, such as when making measurements within indoor environments. When a timing reference, such as that provided by a GPS signal, is lost, the frame boundary timestamp of the CDMA signal itself is used. The parameters of the strongest available PN offset are used. The timing error is determined and the new timing reference timestamp is estimated. The strongest PN is used as the time reference and tau is corrected for. In further embodiments, a user may be able to provide identifying information allowing the estimated timing reference timestamp to be determined even when a GPS signal was never established for providing an initial timing reference.