Abstract

• This paper presents the code tracking method for software defined GPS receiver. A number of methods have been developed to enhance the robustness of Global Positioning System (GPS) receivers when there are a limited number of visible satellites. In this work, code tracking method is developed to improve the accuracy of positions of GPS receiver. The GPS signal consists of the navigation data, the carrier and code sequences for each of the satellite. The signal of each satellite is demodulated using Delay Lock Loop (DLL) for code tracking. The code tracking output errors feedback to Numerically Control Oscillator (NCO) frequency for exact signal lock between GPS signal and NCO signal. In position calculation, each channel of code is controlled by individual loop filter. The code tracking method for software defined GPS receiver is implemented by using MATLAB.