Design of an Assisted GPS Receiver and its Performance Analysis

Abstract

Demands on the indoor positioning capability is being increased. The assisted GPS (AGPS) needs assistance information to acquire the weak GPS signal with strength below -150dBm within 2~3 seconds. This paper proposes an efficient digital correlator scheme for weak signal acquisition in AGPS. It is explained that the proposed digital correlator reduces the squaring loss using a modified non-coherent integration technique. In order to evaluate the performance of the proposed digital correlator, this paper develops an AGPS receiver with the proposed correlator implemented on FPGA (Field Programmable Gate Array) and shows the GPS signal acquisition success rates under various environments. Finally, the performance of the designed AGPS receiver is analyzed using assistance information from the CDMA network using the cell phone.