Study of Terrestrial Radio Determination : Applications and Technology

PDFTech ReportDOT-TSC-RSPA-79-2Automatic trackingAutomatic vehicle monitoringCommunication systemsDisasters and emergency operationsGround vehiclesLaw enforcementLocationLoranMonitoringPosition fixingPublic transitPulse modulationRadioTaxicabsTechnologyTelecommunicationsUtilizationUnited StatesUnited States. Dept. of Transportation. Research and Special Programs AdministrationWard, J. E.Connelly, M. E.Tetewsky, A. K.Massachusetts Institute of TechnologyJohn A. Volpe National Transportation Systems Center, (U.S.)United States. Dept. of Transportation. Research and Special Programs AdministrationNTL-AVIATION-AVIATIONNTL-AVIATION-Air Traffic ControlNTL-GEOGRAPHIC INFORMATION SYSTEMS-GEOGRAPHIC INFORMATION SYSTEMSVolpe National Transportation Systems Center, Technical Reference CenterThe report describes the results of a study of terrestrial radio determination (TRD) applications and technology. Considerable emphasis has been placed on automatic automotive vehicle location or monitoring (AVL or AVM) systems because almost all of the system designs, tests, and operational installations over the past decade have been in these areas. Land vehicle applications considered include law enforcement, taxicabs, public transportation, emergency services, and trucking. The four basic TRD technologies -- hyperbolic, multilateration, proximity, and dead reckoning -- are discussed and compared. Particular points of comparison are accuracy, coverage area, measurement rates, communication requirements, vehicular capacity, and fixed installations required. Also discussed are the pros and cons of centralized vs. decentralized systems, multi-user systems, the advantages of hybridization among TRD technologies to achieve system goals in particular applications, and the results of Loran-C measurements made in Boston as part of the study. The subject of TRD communication has received particular attention, since in many TRD systems, communications is already the limiting factor in system capacity. The problems of digital communications on land-mobile radio channels are presented, existing TRD communications are described and compared, and some suggestions for improvement, perhaps involving development and FCC authorization of new types of radio channels, are presented. Conclusions are presented on the potential benefits of TRD, and on the actions that U.S. Government agencies might take in regard to fostering TRD developments and applications