GPS for accurate synchronization and position measurement must use precise clock, so GPS satellites are equipped with atomic clocks. Clock accuracy is amazing ± 1 second in 1 million years. Using GPS module is available not only acquire position, speed, bet also time and date, so in this post I’ll explain how to do it.
Sirf II module has RS-232 interface for communication and it can be connected to PC Com port. Atmega in Arduino board has UART interface. RS-232 basically is the same UART, only zeros and ones voltage levels are different. To match levels MAX232 driver is used. Today’s GPS modules have UART port, so there isn’t any need for MAX232.
Arduino GPS clock using NMEA protocol - [Link]