Evaluation of a double equipped MEMS IMU based on real flight trial scenarios

The Inertial Measurement Unit (IMU) investigated within the presented work consists of two (optional three) dissimilar sets of MEMS accelerometers and gyros, respectively. Both sets are mounted in one enclosure and thus are subject to the same calibration procedure. Different combinations of these dual sensor sets can be used to exploit the complementary sensor properties, e.g. measurement range, resolution and noise characteristics as well as to benefit from redundancy in airborne applications. To cope with the nonlinear and unsteady behavior of the chosen MEMS sensors, look-up tables and correction polynomials are applied to describe sensor response. The calibration accounts for temperature, acceleration, turn rate, axes nonlinearity, cross-coupling and, regarding the gyros, higher order g-dependencies. The data required for identification of calibration parameters have been obtained using high precision turn tables equipped with temperature chamber and precise vibration excitators at iMAR GmbH, St. Ingbert. The sensor signals can be applied to different integration algorithms, which will be compared in an overall performance assessment. The evaluation is realized using the navigation software frame developed at the Institute of Flight Guidance (IFF) of the Technische Universitaet Braunschweig. The applied algorithms were analyzed using data from high and low dynamic flight trials with the research aircraft D-IBUF operated by the IFF.