Design and implementation of an embedded controller for a vehicle navigation unit

Abstract

This thesis describes the design and implementation of an embedded controller that is used for the Vehicle Navigation Unit (VNU) prototypes that are being developed at the University of Alaska Fairbanks (UAF). The goal of the VNU project is to develop a system that will measure relative position and provide wireless communication between four identical vehicles without the use of GPS signals. Each VNU consists of an antenna and phase detector array, embedded controller, radio modem magnetometer, and a diagnostic computer. The main focus of this thesis is the design and implementation of the embedded controller hardware and software that integrates all the VNU components into an operational system. The embedded controller utilizes the Motorola MC68HC711E9 microcontroller and the Zilog Z85230 Serial Communication Controller that receives and transmits the data serially. The relative distance and bearing between VNUs is estimated by measuring the angle of arrival and received signal strength of the radio frequency packets transmitted by each VNU. The magnetometer is used to monitor the horizontal orientation of the VNU and to serve as a fixed referencefor comparing the relative bearing between vehicles. These raw measurements are archived into a diagnostic computer, which estimates the relative position between the VNUs and provides a graphical representation. These VNU prototypes are designed for ideal environments and are intended to provide a test bed for evaluating signal processing and hardware strategies for mitigating multipath effects. The complete VNU design is presented, started with a functional block diagram of the hardware and software, and concluding with operational tests that demonstrate the performance of the fully integrated prototype.