Time/frequency and transportation

Current and future problems are presented for the land, sea, and air transportation environments that are, or can be, solved using time/frequency technology. Problem areas in transportation encompass vehicle surveillance and location, traffic management, collision avoidance, command and control, communications, navigation, and search and rescue. Time accuracy requirements vary widely from seconds to submicroseconds. The need for time/frequency technology in the orderly and safe movement of people and material is shown to be a function of the type of transportation and environment involved. Various characteristics of the transportation environments are discussed, and time-related aspects of transportation both today and in the future are designated. Transportation statistics indicate tremendous growth in the years ahead with concomitant problems. We consider the impact of the vast difference in the various economic budgets of transportation medium users, and the stated government policy of requiring users of federally operated aids and services to pay their fair share of the costs. Recommendations are presented for broad coordination in the development and introduction of electronic systems for transportation services. We conclude that time/frequency technology can solve some of today´s problems in transportation, and it offers economic integrated-system solutions to future problems with concurrent frequency spectrum conservation. The interrelationships of navigation, communication, and time/frequency systems should encourage coordinated efforts of disciplines in the design of multipurpose systems as opposed to a proliferation of new single-use facilities.