Honeywell International Inc.

Drew A Karnick

Timothy J Hanson

Mark W Weber

Max C Glenn

William Francis Kraetz

Systems and methods for determining accuracy of a smoothed navigation solution using filtered resets are provided. In certain embodiments, a navigation system includes one or more inertial devices configured to detect motion of the system and generate inertial data; and one or more aiding devices configured to generate aiding device measurement data. Further, the navigation system includes one or more processors configured to generate an un-smoothed navigation solution based on the inertial data and the aiding device measurement data, wherein the un-smoothed navigation solution includes an un-smoothed navigation error estimates for a state variable. Further, the one or more processors are configured to calculate a smoothed navigation error estimate for the state variable based on the un-smoothed navigation error estimate. Moreover, the one or more processors are configured to determine whether to provide a smoothed filter reset based on the smoothed navigation error estimate and the un-smoothed navigation solution.

Determining accuracy of smoothed navigation solution using filtered resets

A micro-electro-mechanical systems (MEMS) device comprises at least one proof mass configured to have a first voltage and a motor motion in a first horizontal direction. At least one sense plate is separated from the proof mass by a sense gap, with the sense plate having an inner surface facing the proof mass and a second voltage different than the first voltage. A set of stop structures are on the inner surface of the sense plate and are electrically isolated from the sense plate. The stop structures are configured to prevent contact of the inner surface of the sense plate with the proof mass in a vertical direction. The stop structures have substantially the same voltage as that of the proof mass, and are dimensioned to minimize energy exchange upon contact with the proof mass during a shock or acceleration event.

MEMS device mechanism enhancement for robust operation through severe shock and acceleration

An inertial device for determining an initial condition reference frame for a body is provided. The inertial device includes at least one inertial measurement unit, one or more processing devices, and one or more memory devices. The inertial measurement unit provides rotation information along at least one axis to the one or more processing devices. The one or more processing devices use the rotation information to estimate the current attitude of the body, based on estimates of a total rotation angle experienced by the body from the beginning of body motion to when the inertial measurement unit initialized.

Estimation of an initial condition inertial reference frame

A method of estimating bias errors for an air vehicle in flight under high spin conditions is provided. The method comprises collecting a first set of data samples at a first time and collecting a second set of data samples at a second time. The first time and the second time occur after deployment of the air vehicle and before canard shock. The first and second sets of data samples comprise roll rate data from at least a first gyroscope and acceleration data from at least a first accelerometer. At least a first estimated accelerometer bias from the first and second sets of data samples is calculated.

Real-time compensation of inertial sensor bias errors under high spin rate conditions

A sensor system and method for determining a relative direction to true north is provided. The system comprises at least one angular rate sensor, such as a MEMS sensor, which has an input axis and a rotation axis. The sensor comprises a motor drive structure, a motor signal output from the motor drive structure, a gyroscope, and a sensor rate output from the gyroscope for a sensor rate signal. A frequency divider is in operative communication with the motor signal output, and a spinning device is coupled to the angular rate sensor. A spinning device motor is coupled to the spinning device and is in operative communication with the frequency divider. The spinning device motor has an axis of rotation that is substantially perpendicular to the input axis of the sensor. The spinning device motor is configured to be driven by a periodic signal from the sensor. A position of the spinning device is synchronized to the periodic signal to generate a spinning device position signal. A phase detector is in operative communication with the spinning device motor and with the sensor rate output. The relative direction to true north is determined from a phase differential between the spinning device position signal and the sensor rate signal.

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Blaine, MN, United States of America

Drew A Karnick