A FLEXIBLE, LOW-COST APPROACH TO DIFFERENTIAL OMEGA

D. A. Zomick

Peer Reviewed

Abstract:	THE WORLD-WIDE OMEQA navigation system, used in conjunction with locally-derived differential Omega updates, promises to provide the position-fixing accuracy and reliability required 1.) by commercial aircraft for area navigation in even heavily-trafficked terminal locales, 2.) by military aircraft for the successful execution of the vast majority of tactical missions, and 3.) by space shuttle and similar vehicles for re-entry navigation during the post-blackout portion of flight. A mechanization of the differential Omega concept is presented which provides maximum flexibility, allowing users to determine their positions with circular (rho-rho), hyperbolic, or pure differential mechanizations and yet does not require the differential ground subsystem to contain an expensive, highly-accurate oscillator which is normally associated with rho-rho capabilities. The hardware and software implementations are outlined and a rationale for the particular navigation and updating mechanization selected is presented. It is shown that while skywave propagation variations and local oscillator off-sets are not separated by the ground subsystem, this ambiguity need not introduce errors to user aircraft. In fact, users operating in the circular mode can generally achieve greater accuracy than for a purely hyperbolic mechanization in which all clock errors were eliminated. The implementation described is incorporated as a selectable mode of operation in the Omega subsystems to be delivered by Bendix Navigation and Control to the FAA for its differential Omega evaluation program.
Published in:	NAVIGATION: Journal of the Institute of Navigation, Volume 21, Number 4
Pages:	288 - 297
Cite this article:	Zomick, D. A., "A FLEXIBLE, LOW-COST APPROACH TO DIFFERENTIAL OMEGA", NAVIGATION: Journal of The Institute of Navigation, Vol. 21, No. 4, Winter 1974-1975, pp. 288-297.
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