APPARATUS AND METHOD FOR MAINTAIN OF TIME SYNCHRONIZATION IN ASSISTED GLOBAL POSITIONING SYSTEM RECEIVER

摘要

The present invention relates to an apparatus and method that, to maintain time synchronization with the CDMA base station correctly while the portable device search and track the GPS signals in the CDMA system, this invention is a CDMA (Code Division Multiple Access) communication in the in the system location estimation method of a portable device using the (Assisted Global Positioning system) AGPS scheme, received, using the received satellite signal to process the satellite signal received by the Doppler value of the satellite through the AGPS server the code frequency bias by using the difference of the measuring of the Doppler value of the satellite and, as the received Doppler values ​​and the measured Doppler values ​​( ) The code frequency bias process and the calculation for calculating a value ( ) Code bias by considering the values ​​and the search time ( ) Calculating a value, and the calculated bias code ( ) To compensate the value characterized in that it comprises the step of calculating a pseudo distance of the satellite. ; AGPS, CDMA, GPS receiver, the time error, bias cord, cord frequency bias