A ground-based test facility for airborne magnetic gradient tensor instruments simulating calibration flights

Progress is slow in terms of the research and evaluation of calibration algorithms for full tensor magnetic gradient instruments using airborne tests. The main reason is that, based on knowledge gained by actual calibration flights, problems exist regarding high risk, high costs, and long development cycles. In this paper, we describe a ground-based simulation facility for calibration flights which combines the nonlinear aerodynamic model with a magnetic interference model. Environmental magnetic fields can be calculated and produced by tri-axial coils, which are measured by the magnetic tensor gradiometer in calibration flights. Influence from systematic errors and magnetic interference can be extracted from the simulated calibration flight provided by the facility. Compared to system evaluation in airborne operation, this method has the benefit of zero risk, low costs, and short duration of evaluation cycles. In view of ground-based multi-degree of freedom motion platforms, it has the advantages of simple manufacture, good dynamic characteristics, and adaptability to different aircraft types.