Cloudnav Inc.

Invensense, Inc.

Nathan Royer

Erik E Anderson

Derek Keith Shaeffer

David Sachs

Stephen Lloyd

David William Devries

Doug Vargha

Kerry Keal

Devices and methods for automatic calibration of rate gyroscope bias are described. One example method includes receiving, while the device is in motion, a plurality of measurements from one or more sensors, including a gyroscope, in the device. In this example, the plurality of measurements is acquired over a time period. The method also includes identifying one or more time segments, within the time period, having a low motion activity of the device by comparing a computed value associated with a motion of the device to a predetermined threshold. The method further includes determining, based on one or more measurements acquired over the one or more time segments, a degree of motion metric for at least one of the one or more sensors, and determining, based on the degree of motion metric for the at least one of one or more sensors, an estimate of a bias of the gyroscope.

Methods and systems for automatic calibration of gyroscope bias in the presence of motion

An electronic device configured for real-time calibration of an on-board accelerometer. A plurality of acceleration measurements are collected from the accelerometer to form a data set. An accelerometer error correction model is maintained that includes bias error calibration parameters, sensitivity calibration parameters, and cross-axis calibration parameters that each specify respective weights for each of bias error, sensitivity error, and cross-axis error. Calibration values are determined for one or more of the bias error calibration parameters, the sensitivity calibration parameters, and the cross-axis error calibration parameters for the data set of acceleration measurements using the accelerometer error correction model. A true acceleration vector may be determined that corresponds to a subsequently received acceleration measurement using the determined calibration values.

Real-time accelerometer calibration

The present invention relates to a combination of a 6-axis motion sensor having a 3-axis gyroscope and a 3-axis linear accelerometer, a motion processor and a radio integrated circuit chip (IC), wherein the intelligence in the motion processor enables the communication between the motion sensor, the radio IC and the external network. The motion processor also enables power savings by adaptively controlling the data rate of the motion sensor, depending on the amount or speed of the motion activity.

Wireless motion processing sensor systems suitable for mobile and battery operation

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San Jose, CA, United States of America

Nathan Royer