Study of Real-time Filtering for an Inertial Measurement Unit (IMU) with Magnetometer in a 155mm Projectile

V. Fleck, E. Sommer and M. Brokelmann

Abstract:	In this paper we present the study of active flight path correction capabilities in a spin stabilised 155mm-projectile. For any kind of trajectory correction the instantaneous flight conditions must be known very well. To determine the flight characteristics of a projectile, accurate aerodynamic coefficients must be available. Our approach consists of a telemetry system which includes acceleration sensors, gyrometers and a threeaxis- magnetic sensor embedded in a projectile at a well known location. These sensors define a 6DOFmeasurement system and are integrated and calibrated in our laboratories for the test firings. The validation of the sensor-based flight path calculation is done by measuring the trajectory of the projectile by a radar system. Exact backward calculations of the flight condition immediately after launch confirm the quality of our measurement data. This precision of the algorithm is obtained by a multi-parameter-estimation of the aerodynamic coefficients. In the algorithms an extended Kalman filter is used. It is based on a rotation matrix which turns the projectile frame into the velocity frame to separate the attitude from the velocity vector. The roll angle during flight could be determined by a combination of the acceleration and magnetic sensor data, although the projectile is spin stabilized. We reached a relative error less than 0.2%. Real measurement data are shown in this report. Future work will focus on the implementation of the algorithm for different steering systems. The algorithm and assumptions have to be simplifying for a real-time data reduction system which is the base for an active flight control.
Published in:	Proceedings of IEEE/ION PLANS 2006 April 25 - 27, 2006 Loews Coronado Resort Hotel San Diego, CA
Pages:	803 - 807
Cite this article:	Fleck, V., Sommer, E., Brokelmann, M., "Study of Real-time Filtering for an Inertial Measurement Unit (IMU) with Magnetometer in a 155mm Projectile," Proceedings of IEEE/ION PLANS 2006, San Diego, CA, April 2006, pp. 803-807. https://doi.org/10.1109/PLANS.2006.1650676
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