The application of spread spectrum datalinks to GPS-based air traffic navigation, surveillance, and control

A spread spectrum datalink is considered as a potential candidate for support of DGPS-based navigation, surveillance, and control. Spread spectrum communications is a technology that for years has been exploited in military communications because it could provide the desirable characteristics of either immunity from intentional jamming or low probability of interception. More recently, the technology has been applied to civil communications because the same properties that result in those characteristics also provide for an efficient mechanism for multiple users to simultaneously share a band of frequencies on a noninterfering basis. The paper provides a brief review of the basic concepts of spread spectrum communications. That information is then used to support a discussion of the rationale for considering spread spectrum techniques in this air traffic control application. The advantages and disadvantages relative to alternative approaches are presented; and, the most appropriate spread spectrum designs in terms of both signal architecture and hardware implementation are discussed. The paper describes an effort underway at Harris Air Traffic Control Systems Division on a FAA contract. The program goal is to demonstrate a spread spectrum datalink in support of a GPS-based airport surface traffic management system. It is believed that it will result in the first ever demonstration of a spread spectrum datalink being utilized at an airport to help solve a real air traffic control problem.<
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