Achieving synchronization and syntonization using GPS receivers

Abstract

Every day, millions of people ask what time it is. Depending on the person and their reason for asking, the required accuracy and precision of an answer varies. Humans are not the only ones that care about time though, (perhaps more importantly) countless electronic devices ranging from cell phones to satellites do as well. Without accurate and precise frequency references and timekeeping systems, many of the electronics in use today would function incorrectly. The primary goal of this thesis was to achieve both synchronization and syntonization using a Global Positioning System (GPS) receiver called Namuru, which was developed at the University of New South Wales (UNSW). In the former case, this means that the pulse per second (PPS) signals output by the receiver should be aligned with the second boundaries of GPS Time (GPST). In the latter case, this means that the frequency of the voltage-controlled temperature-compensated crystal oscillator (VC-TCXO) onboard the receiver should be equal to its setpoint. The secondary goal of this thesis was to develop a clock model that accurately simulated the synchronization and syntonization performance of the receiver. The tertiary goal of this thesis was to develop supplementary features for the receiver like position-hold and holdover modes. In order to achieve these goals, several new capabilities were added to the receiver and much work was done in a number of different areas, such as field-programmable gate array (FPGA) programming, writing firmware, modifying hardware, and modeling.