A Comparison of Automatic Vehicle Tracking Systems

Abstract

Many segments of the transportation industry will benefit from an automatic vehicle tracking and monitoring system. Such a system automatically reports the position of a number of vehicles (groundborne, seaborne and airborne) to a central location. Dispatchers, such as police, bus or taxi, could more efficiently use their resources if they could track the location of the vehicles they are controlling. Ships on a seaway could be more efficiently scheduled into docks or locks if their position and speed were being tracked. Trucking companies could more effectively protect their cargos from theft or hi-jacking if they could monitor the location of the trucks. A few automatic vehicle tracking systems have been implemented. As an example the Chicago Metropolitan Bus System has been evaluating a system. The Urban Mass Transportation Administration of the Department of Transportation is conducting a program to determine the best system for “Automatic Vehicle Monitoring”. Tests have been conducted of at least four RF positioning systems to determine which of these technologies meet DOT/UMTA requirements. The next phase will be a trial implementation of one of these tested systems. This paper summarizes the stated user requirements as determined by DOT/UMTA, St. Lawrence Seaway Authority, Forestry Service, Railroads and others. These user requirements include positioning accuracy, number of vehicles to be handled simultaneously, coverage area and implementation and operating costs. A comparison of several technologies is then presented. A very brief description of each system, including Loran–C, Differential Omega, RF trilateration, sign-post and dead reckoning is presented with a comparison of the advantages and disadvantages in view of the user requirements. A cost comparison is presented which compares the implementation and operating costs of the different systems. Overall efficiency is compared; i.e. cost per user, rf spectrum efficiency, etc. A summary of this comparison concludes that a Loran–C Automatic Tracking System is the most efficient alternative to the requirement for an automatic vehicle positioning system. A description of a Loran–C System then follows, which briefly describes the major system components. Implementation and operating costs are presented. The solution to the two prime problems of a Loran AVM System are described—namely a low-cost receiver and the availability of relatively low-cost, small, Loran–C chains presently in production.