A polar flight guidance method based on polar-plane rhumb route

When civil aircraft flies along a great circle route, the route is usually approximated by multiple rhumb routes segments in order to guide easily. However, traditional guidance methods become inadequate for the flight in polar regions since great circle routes exhibit non-constant azimuth, while rhumb routes converge into high-curvature spirals. To solve these problems, a polar guidance method based on the polar-plane rhumb route was proposed in this paper. Firstly, the polar plane was defined and a polar-plane parameter projection algorithm was derived, therefore overcoming the limitations of traditional mechanization schemes that only work within specific ranges and require complex coordinate system switching calculation based on navigation area. Then, according to the projection characteristics of great circle routes on the polar plane, the polar-plane rhumb route was defined and its route equations were deduced. The proposed polar-plane rhumb route maintains constant polar-plane azimuth while possessing the route length comparable to that of the great circle route, thus being more suitable as a reference route in polar regions. Finally, a flight guidance algorithm based on polar-plane rhumb route was derived and relative polar flight simulation was conducted based on a transport aircraft model. The simulation results demonstrate that the aircraft guided based on polar-plane rhumb route can fly with high precision in polar regions.