Differential omega in the domestic air traffic control environment

TLDR: A proposed configuration of the differential ground monitor stations is examined and it is shown that approximately fifty will be required to obtain coverage for the forty-eight contiguous states, and a differential message format is developed.

Abstract: At the present time there is interest within the aviation community to determine how the Omega navigation system could possibly be applied to domestic IFR navigation. Assuming Omega provides a sufficient navigation information rate for a significant number of users, there are two Omega methods that are contenders for utilization in the air traffic control system; Composite Omega and Differential Omega. It appears that Differential Omega would be significantly more accurate than Composite Omega. Furthermore, Composite Omega accuracies may not be sufficient for future domestic ATC requirements, whereas Differential Omega would likely meet these accuracy requirements. However, a complete implementation of the differential technique involves several fundamental considerations before this method can be considered further. Some of these considerations are the configuration and the required number of ground monitoring stations, the differential correction message format and data rate, the practicality of various alternatives for the ground-to-air link, and resulting receiver complexity. In analyzing these considerations, a proposed configuration of the differential ground monitor stations is examined. Using a technique to locate these monitor stations, it is shown that approximately fifty will be required to obtain coverage for the forty-eight contiguous states. Based on the number of monitor stations necessary and the amount of correction information required, a differential message format is developed. The variability of the Omega propagation error sources is analyzed, so that a differential correction update rate can be specified. The alternatives for the differential communications link for complete coverage are assessed with consideration given to maximizing the benefits of the differential system. The implications of the differential system with respect to airborne complexity is also discussed.