System and method for generating precise code based and carrier phase position determinations

摘要

A GPS system that includes a GPS beacon beacon that receives a plurality of GPS signals. Each of the GPS signals haa a carrier component and a pseudo-random code component. The beacon generates in response to the received GPS signals a plurality of beacon signals. Each of the plurality of beacon signals has a carrier component phase locked to one of the carrier components of the received GPS signals and a pseudo-random code component phase locked to one of the pseudo-random code components of the received GPS signals. The beacon then transmits the plurality of beacon signals. The system also includes a GPS receiver. The GPS receiver can make Code Based Differential GPS position determinations by making range measurements for each of the pseudo-random code components of the GPS and beacon signals and in response computing values representing a position. Additionally, the GPS receiver can make Carrrier Phase Differential GPS position determinations by first making phase measurements for each of the carrier components of the GPS and beacon signals at a plurality of measurment epochs during an initialization period. It then computes initialization values in response to these phase measurements for the GPS and beacon signals. Then, at a subsequent epoch after the initialization period, it computes a position in responsive to the initialization values and in response to the phase values for the GPS and beacon signals measured at the subsequent measurment epoch.