A SDR-based GPS Receiver with Low Accuracy of Local Oscillator

A high accuracy local oscillator of GPS receiver is usually a basic requirement for a successful fix due to the Doppler effect of GPS signals. Most of software defined radios are equipped with low accuracy oscillator, it is difficult to realize GPS positioning in such platforms. In this paper, we propose a frequency calibration method to narrow the frequency search range of the acquisition of GPS satellites so that the GPS C/A signal can be tracked and decoded successfully. We develop a SDR-based GPS receiver using a low cost PlutoSDR transceiver with built-in low accuracy oscillator. An outdoor GPS fix was conducted with positioning accuracy HDOP 2.4.