Determining the attitude of the advanced crew transportation spacecraft federatsiya from measurements of global navigation satellite systems

The paper discusses the functionality of the Satellite Navigation Equipment (SNE) for the advanced Crew Transportation Spacecraft (CTS) Federatsiya, algorithms for determining its attitude exclusively from measurements of a global satellite navigation system without using any additional navigational or gyroscopic devices. It proposes methods for determining the attitude with successive increases in accuracy, providing attitude determination in minimal time: - the method based on the filling of fields of view of the antennae with signals from navigation satellites, which provides a rough determination of the attitude to within 20-30° over a period of 2 to 3 seconds; - the method based on phase increments, which provides attitude determination to within 2-3° over a period of 50 to 100 seconds; - the method based on phase measurements, which provides continuous attitude determination to within -0,5° in 10 seconds after the mode is started. The paper defines the solvability criterion for the attitude problem, introduces the notion of Attitude Dilution of Precision (ADOP) and provides its rigorous definition by analogy with the standard notion of Geometric Dilution of Precision (GDOP) in the navigation problem. The paper compares the performance of an SNE, which fulfils the functions of a Strapdown Inertial Navigation System (SINS) with the performance of a conventional SINS built around various gyroscopic devices.