Design and implementation of automatic route guidance systems for land-based applications.

摘要

Automation of land-based navigational activities is having a positive impact on improving safety and efficiency in the transportation sector. The advancements in key technologies such as microcomputers, mass storage devices, positioning techniques, geographic information systems, and communication systems have made this automation possible, more reliable and cost effective. The present trend in automating land-based navigational activities is towards building computer-based systems. These computer-based navigational systems, however, need to be developed as easy to use and inexpensive information systems (navigational information systems), if they are to be accepted by users.;The contribution of this research relates to the theory and practice of a class of navigational information systems called automatic route guidance systems (ARGSs). In this thesis, the conceptualization, design, and implementation of ARGSs are discussed. Positioning, locating, optimal route finding, kinematic positioning, and route guidance are identified as the principal activities performed in an ARGS. To satisfy a wide range of applications, two configurations of ARGSs--stand-alone and dispatch--are proposed. To implement ARGSs, an evolutionary approach is recommended. Two generations of ARGSs in this process are recognized: conventional (first generation) and intelligent (second generation) ARGSs. The components considered in building conventional ARGSs are algorithms, data processing, and conventional software engineering. The technique considered for building intelligent ARGSs, in addition to those for building conventional ARGSs, is knowledge processing.;A conventional stand-alone ARGS was designed and prototyped. The positioning systems employed were a GPS receiver, differential odometry, and map matching. A relational data model was used to structure the road network data base required in this prototype. Extensive tests were performed and the positive results validated the original generic concept and design put forth by the author.;A generic conventional dispatch ARGS called PCG (Position, Communications, and GIS) was designed, developed, and implemented. The GPS technique for positioning and a private radio (VHF) for communications were used in this dispatch system. The GIS component of PCG was designed, developed, and implemented entirely by the author and can handle a number of functions such as address finding and optimal route determination. For the road network data base, the Area Master Files (AMF) were customized and used.;An intelligent ARGS was designed by the author and its implementation techniques are described. The challenging task in this design was the real-time constraint of ARGSs. In this design, knowledge about the system components, application, and environment is included. Clearly, the acquisition of this knowledge and its introduction into a shell requires a separate investigation, therefore, the implementation of this design was not made. A strategy for the development of two specific shells, one for intelligent stand-alone ARGSs and one for intelligent dispatch ARGSs, was proposed by the author.