Inertial reference unit

About: Inertial reference unit is a research topic. Over the lifetime, 1306 publications have been published within this topic receiving 22068 citations. The topic is also known as: IRU.

Calibration of an IMU-Camera Cluster Using Planar Mirror Reflection and Its Observability Analysis

Abstract: This paper describes a novel and a low-cost calibration approach to estimate the relative transformation between an inertial measurement unit (IMU) and a camera, which are rigidly mounted together. The calibration is performed by fusing the measurements from the IMU-camera rig moving in front of a planar mirror. To construct the visual observations, we select a set of key features (KFs) attached to the visual inertial rig where the 3-D positions of the KFs are unknown. During calibration, the system is navigating in front of the planar mirror, while the vision sensor observes the reflections of the KFs in the mirror, and the inertial sensor measures the system's linear accelerations and rotational velocities over time. Our first contribution in this paper is studying the observability properties of IMU-camera calibration parameters. For this visual inertial calibration problem, we derive its time-varying nonlinear state-space model and study its observability properties using the Lie derivative rank condition test. We show that the calibration parameters and the 3-D position of the KFs are observable. As our second contribution, we propose an approach for estimating the calibration parameters along with the 3-D position of the KFs and the dynamics of the analyzed system. The estimation problem is then solved in the unscented Kalman filter framework. We illustrate the findings of our theoretical analysis using both simulations and experiments. The achieved performance indicates that our proposed method can conveniently be used in consumer products like visual inertial-based applications in smartphones for localization, 3-D reconstruction, and surveillance applications.

Integrity monitoring of inertial reference unit

Abstract: Systems, methods, and machine-executable programming products adapted for the control of aircraft or other vehicles by receiving from at least one Inertial Reference System (IRS), including a plurality of Inertial Reference Units (IRUs), signals representing vehicle state data; receiving from at least one Augmented Direct Mode Sensor (ADMS) signals representing independently-acquired vehicle state data corresponding to at least a subset of the signals received from the IRS; performing signal selection and fault detection processes on the signals received from the at least one IRS and on the corresponding signals received from the ADMS; based at least partly on the signal and fault detection processes, determining whether at least one component of at least one of the IRS and ADMS is in a fault condition; and based on the fault condition, providing to at least one vehicle control system device one or more vehicle control command signals.

Minimax failure detection and identification in redundant gyro and accelerometer systems.

Abstract: Minimax algorithms for failure detection and identification for redundant noncolinear arrays of single-degree-of-freedom gyros and accelerometers are described. These algorithms are optimum in the sense that detection occurs as soon as it is no longer possible to account for the instrument outputs as the outputs of good instruments operating within their noise tolerances, and identification occurs as soon as it is true that only a particular instrument failure could account for the actual instrument outputs within the noise tolerance of good instruments. An estimation algorithm is described which minimizes the maximum possible estimation error magnitude for the given set of instrument outputs. Monte Carlo simulation results are presented for the application of the algorithms to an inertial reference unit consisting of six gyros and six accelerometers in two alternate configurations.

Design and Calibration for a Smart Inertial Measurement Unit for Autonomous Helicopters Using MEMS Sensors

Abstract: In this paper, we present the design of 3D Inertial Measurement Unit(IMU), which consists of 3D accelerometers, 3D gyroscopes and 3D magnetic sensors for automatic control of aerial robots. It has characteristics with very small size, low power consumption, high distinguishing ability and inexpensive. The novel automatic initial calibration of 3D accelerometers and 3D magnetic sensor, based on Newton's method, is implemented. The experiments show the hardware design is in effect and the calibration can reduces the offset error, scaling error and non-orthogonal error efficiently.

Study of inertial measurement unit sensor

Abstract: This paper contains the study about the inertial measurement unit (IMU) sensor. The study is about the types available in markets and also some research on IMU. In this paper also included the uncertainty of some IMU been used and comparison between some IMU manufacturers. Then the combination of IMU with GPS can provide more effective result for navigation, guidance and controlling system for aircraft such as UAV (unmanned aerial vehicle).