Research on errors of magnetic field sensors and algorithms for determining 3D spatial deviation in aeronautical heading reference systems

In the XXI century, magnetic measurements are widely used in diverse applications. This paper presents the practical application of magnetic measurements in the Magnetic Heading System (MHS) and the Helmet Mounted Cueing System (HMCS) on board of civilian and military aircrafts. The area of application of magnetic field sensors and the corresponding measuring ranges and errors are presented. The research problem and the method of its solution were defined in relation to the determination of spatial deviation occurring in aviation heading indicating systems for various angles of spatial orientation. The mathematical relationships describing the components of the Earth's magnetic field and disturbing fields originating from hard and soft magnetic iron, which are structural elements of the aircraft, were given. An innovative element is a simulation model, developed in the Matlab-Simulink package, enabling the determination of 2D horizontal deviation and 3D spatial deviation for the given spatial orientation angles. Selected results of research on the influence of inaccuracies in the positioning of magnetometers and the possibility to identify their errors using the spectral analysis applied to the course of magnetic deviation are presented.