Showing papers on "GNSS augmentation published in 1977"

A comparative performance analysis of modern ground-based, air-based and satellite-based radio navigation systems

Abstract: This paper presents a comparison of the performance characteristics and limitations of the major radio navigation systems which are currently operational or under development. The comparative analysis concentrates on six critical operational parameters which are considered basic to both civil and military applications. These parameters are Volumetric Coverage, Signal Reliability, Accuracy, Data Content, Application Versatility and User Equipment Cost. The ground–based systems analyzed are VORTAC, Loran–C, Omega and Differential Omega. The air–based systems include airborne radar position fixing, Doppler Navigation and the Joint Tactical Information Distribution System (JTIDS) Relative Navigation (RELNAV) function. The satellite–based systems covered are the Navy Navigation Satellite System (NNSS) and the Global Positioning System (GPS). Each of these systems is described and examined on the basis of the six evaluation criteria and a composite system comparison is presented. It is shown that the true cost effectiveness of a navigation system is a strong function of volumetric coverage, data content and application versatility, as well as the more frequently–used parameters of accuracy and signal reliability. The high degree of development maturity of some of the ground–based systems have led to very–low–cost user equipment and this will result in their continued use. The time–synchronous systems, i.e., GPS and JTIDS RELNAV, have unique performance and versatility advantages and these powerful systems will be used widely during the next decades, provided user equipment cost is reduced to acceptable levels. In order to increase over–all cost effectiveness, it is suggested that these latter systems be interconnected so as to take advantage of certain mutually beneficial characteristics.

Maritime and Aeronautical Satellite Navigation Systems

Abstract: This paper inciudes a brief survey of the generic types of radio navigation aids, including satellite navigation; then a more detailed review of the TRANSIT and NAVSTAR systems, thus encompassing the principal developmental and operational satellite navigation systems. The precision and accuracy of these systems, their basic operating characteristics, and the ancillary equipment required for their operations will be covered. The technical problems associated with performance, reliability and cost will be described.