In recent years, microelectromechanical system (MEMS) inertial sensors (3D accelerometers and 3D gyroscopes) have become widely available due to their small size and low cost. Inertial sensor measurements are obtained at high sampling rates and can be integrated to obtain position and orientation information. These estimates are accurate on a short time scale, but suffer from integration drift over longer time scales. To overcome this issue, inertial sensors are typically combined with additional sensors and models. In this tutorial we focus on the signal processing aspects of position and orientation estimation using inertial sensors. We discuss different modeling choices and a selected number of important algorithms. The algorithms include optimization-based smoothing and filtering as well as computationally cheaper extended Kalman filter and complementary filter implementations. The quality of their estimates is illustrated using both experimental and simulated data.

In this paper a comparison is made between four frequently encountered resampling algorithms for particle filters. A theoretical framework is introduced to be able to understand and explain the differences between the resampling algorithms. This facilitates a comparison of the algorithms with respect to their resampling quality and computational complexity. Using extensive Monte Carlo simulations the theoretical results are verified. It is found that systematic resampling is favourable, both in terms of resampling quality and computational complexity.

An optimization-based approach to human body motion capture using inertial sensors, 2014, In Proceedings of the 19th IFAC World Congress, 2014, 79-85. ISBN: 978-3-902823-62- Abstract: In inertial human motion capture, a multitude of body segments are equipped with inertial measurement units, consisting of 3D accelerometers, 3D gyroscopes and 3D magnetometers. Relative position and orientation estimates can be obtained using the inertial data together with a biomechanical model. In this work we present an optimization-based solution to magnetometer-free inertial motion capture. It allows for natural inclusion of biomechanical constraints, for handling of nonlinearities and for using all data in obtaining an estimate. As a proof-of-concept we apply our algorithm to a lower body configuration, illustrating that the estimates are drift-free and match the joint angles from an optical reference system.

Abstract-In this work we present an approach to combine measurements from inertial sensors (accelerometers and gyroscopes) with time of arrival measurements from an ultrawideband system for indoor positioning. Our algorithm uses a tightlycoupled sensor fusion approach, where we formulate the problem as a maximum a posteriori problem that is solved using an optimization approach. It is shown to lead to accurate 6D position and orientation estimates when compared to reference data from an independent optical tracking system. To be able to obtain position information from the ultrawideband measurements, it is imperative that accurate estimates of the ultrawideband receivers' positions and their clock offsets are available. Hence, we also present an easy-to-use algorithm to calibrate the ultrawideband system using a maximum likelihood formulation. Throughout this work, the ultrawideband measurements are modeled by a tailored heavy-tailed asymmetric distribution to account for measurement outliers. The heavy-tailed asymmetric distribution works well on experimental data, as shown by analyzing the position estimates obtained using the ultrawideband measurements via a novel multilateration approach.

Abstract-In this paper we propose a 6DOF tracking system combining Ultra-Wideband measurements with low-cost MEMS inertial measurements. A tightly coupled system is developed which estimates position as well as orientation of the sensorunit while being reliable in case of multipath effects and NLOS conditions. The experimental results show robust and continuous tracking in a realistic indoor positioning scenario.