GPS transmitter and receiver signal simulation

Nowadays, satellite systems that has started to be popular since early 1990s, are used in many military and civil applications. At the beginning, although the satellite-based navigation systems were used for only military purposes, they were opened up civil use over time and have begun to be used as navigation aids for all means of transport. One of the global positioning determination system developed by different countries is GPS (Global Positioning System) developed by USA. The system planned to service with 24 satellites, which was 21 operational and 3 spare, currently services to users with 31 operational satellites. Nowadays, GPS satellites broadcast in theree different frequencies along with L5 (1176,45 MHz) frequency added to the existing L1 (1575,42 MHz) and L2 (1227,60 MHz) frequencies. The aim of this study is to simulate GPS L1 signal and to design the user interface. In this framework, first of all, L1 signals are generated in four satellites selected by the user then these signals are reached to the receiver by interfering with the noise. In receiver stage after the coming signals are demodulated, navigation message including so important informations for the users is obtained. Signal processing techniques used in the simulation are implemented by means of MATLAB (Matrix Laboratory) R2015b. An interface is designed by using MATLAB-GUI (Graphical User Interface) to display the results and position informations which the receiver obtains from the coming signals. Application stage of the study enables to show the calculated and real receiver positions on the map using designed interface. Also via the interface it is possible to analyse signal outputs of process that occur from generation of satellite signal to navigation message obtained in the receiver.