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.

Gps-aided inertial navigation method and system

Abstract: A GPS-aided inertial navigation method includes providing multiple sensors including multiple inertial measurement units (IMUs) and at least one global positioning system receivers and antennas (GPSs) and computer with embedded navigation software. The computer interfaces with all IMUs and all GPS receivers; running, in parallel, in multiple standard inertial navigation (IN) schemes; computes the mean of all the INSs to obtain a fused IN solution for the IMUs' mean location; computes the mean of all the GPS solutions to obtain a fused GPS solution for the GPS antennas' mean location; applies a lever-arm correction, with the vector from the mean IMU location to the ‘mean antenna’ location, to the fused GPS solution; feeds the fused IN solution and the lever-arm corrected fused GPS solution to a single navigation filter, as if there were a single IMU and a single GPS; and runs an IMU/IN/GPS correction module.

Positioning apparatus and positioning method

Abstract: A positioning apparatus includes: a unit that calculates an inertial navigation positioning result by performing position calculation using inertial sensor data and stores the inertial navigation positioning result in a storage unit with time information being added to the inertial navigation positioning result; a unit that calculates a GPS positioning result by using GPS positioning data; a unit that performs a coupling process for the GPS positioning result and the inertial navigation positioning result, which is stored in the storage unit, having the same time information as time when the GPS positioning data is acquired; a unit that corrects the inertial navigation positioning result stored in the storage unit based on information of a position error, an attitude error, a velocity error, and a bias error of the inertial sensor that are acquired through the coupling process.

Automatic calibration of a motion capture system based on inertial sensors for tele-manipulation

Abstract: We introduce an intuitive way of controlling a manipulator. This control should fulfill several constraints like low room consuming and operable in a short time. With this constraints in mind we chose an inertial sensor based motion capturing system. Such systems have to be adapted to the user. We present a method to adapt the system by a fast calibration while it is been used. The calibration does not require specified given motions. The soundness of the system is shown in synthetic and real experiments.

Continuous Tuning and Calibration of Vibratory Gyroscopes

Abstract: A method of control and operation of an inertial reference unit (IRU) based on vibratory gyroscopes provides for continuously repeated cycles of tuning and calibration. The method is intended especially for application to an IRU containing vibratory gyroscopes that are integral parts of microelectromechanical systems (MEMS) and that have cloverleaf designs, as described in several previous NASA Tech Briefs articles. The method provides for minimization of several measures of spurious gyroscope output, including zero-rate offset (ZRO), angle random walk (ARW), and rate drift. These benefits are afforded both at startup and thereafter during continuing operation, in the presence of unknown rotation rates and changes in temperature. A vibratory gyroscope contains a precision mechanically resonant structure containing two normal modes of vibration nominally degenerate in frequency and strongly coupled via a Coriolis term. In the case of the cloverleaf design MEMS gyro, these normal modes of vibration are plate rocking modes. The rocking motion of the plate is described by giving two angles, theta(sub 1) and theta(sub 2). A proof mass consisting of a post orthogonal to the plate ensures a high degree of Coriolis coupling of vibratory energy from one mode into the other under inertial rotation. The plate is driven and sensed capacitively across a few-microns-wide gap, and the normal mode frequencies can be tuned electrostatically by DC voltages applied across this gap. In order to sense rotation, the resonator plate is caused to rock in the theta(sub 1) direction, then any small motions in the theta(sub 2) direction are sensed, rebalanced, and interpreted as inertial rotation. In this scenario, the "drive" has been assigned to the theta(sub 1) direction, and the "sense" has been assigned to the theta(sub 2) direction.