Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: In one embodiment, an inertial device for determining an initial condition reference frame for a body is provided. The inertial device comprises 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 uses the rotation information to estimate the current attitude of the body, based on estimates of a total rotation angle from experienced by the body from the beginning of body motion to when the inertial measurement unit initialized.

Abstract: 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.

Abstract: 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.

Abstract: Methods and apparatus for a MEMS sensor package are provided. In one embodiment, a MEMS sensor package comprises a MEMS sensor; a sensor body permeable to gas leakage at a first leak rate; a backfill gas that pressurizes the sensor body to a backfill pressure; wherein the backfill pressure provides a dampening of the MEMS sensor; and wherein the backfill pressure is set such than any increase in pressure within the sensor body due to gas leakage will not cause a deviation in a Q value of the MEMS sensor beyond a predefined range for at least a specified design service life for the MEMS sensor package.

Abstract: 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.

Abstract: A system for conditioning a sensor die. The sensor die may have a sensor wafer and a substrate wafer anodically bonded together. The sensor die may have an inertial device such as an accelerometer or a gyroscope. The device has a scale factor that may change with a bowing of the sensor die. The die may be bonded at a high temperature to bumps on a surface of a package, but may develop a bow when cooled down to a temperature such as room temperature when the coefficients of thermal expansion of the die and the package are different. The bump material may enter a yield state. The package and the die may be subjected to a high gravity environment to reduce or reverse the bow. After the package is removed from the high gravity environment, the bow may return but at a smaller magnitude when subject to similar conditions.

Abstract: Methods and systems for controlling the internal dampening of MEMS sensors is provided. In one illustrative embodiment, a MEMS sensor is provide that can be tunable to a desired Q value, and the Q value may be held relatively constant over the expected life of the sensor. The MEMS sensor package may include a chamber that houses a MEMS sensor. An inert gas may be provided in the chamber at a desired or specified pressure, wherein the inert gas may be backfilled into the chamber after the chamber is evacuated. The pressure of the inert gas may be set to achieve a desired Q value.

Abstract: A feedback circuit for generating an output signal from a sensor that makes changing electrical and temperature characteristics of the sensor and any sensing medium irrelevant. The sensor is placed in the forward loop of the circuit to make the output depend on the area of the parallel plates the sensor, not on any electrical or temperature characteristics of the sensor or sensing medium. A liquid filled sensor having parallel conducting plates, one solid and the other being split into two differential plate sections may be used in the forward loop as a liquid level sensor or an inclinometer. Alternative sensors such as inductive sensors may also be used.

Abstract: The present invention provides a vertical reference that includes sensors providing signals indicative of angular tilt from the predetermined reference axis and the rate of angular tilt; an integrator to integrate the angular rate signal to provide a dynamic angular tilt signal; a pendulum to provide a signal indicative of angular displacement relative to the predetermined axis; a first amplifier for filtering and amplifying the dynamic angular tilt signal and the angular displacement signal to produce a first amplified signal; a second amplifier for filtering and amplifying the dynamic angular tilt signal and the angular displacement signal to produce a second amplified signal; and a dual input amplifier for combining and amplifying the first and second amplified signals to produce an output signal indicative of vertical reference and attitude.