Determining spacecraft and airplane angular orientation from star photographs

The advantages of determining spacecraft angular orientation from star photographs include the documental nature and objectivity of the photographic image and also the high accuracy of construction of the reference system based on the stars. Use of the method presupposes installation aboard the vehicle of a specialized photographic camera adapted for photographing the stellar sky. From the mathematical viewpoint, the essence of the method amounts to: (1) Certain directions in space are identified and their direction cosines are determined in a specified coordinate system. (2) The direction cosines of these same directions are determined relative to a coordinate system fixed with the vehicle. (3) The sought angular orientation of the vehicle is calculated using the coupling equations between the specified and vehicle-fixed coordinate systems. In principle, vehicle angular orientation can be determined relative to any given reference system.