The present disclosure includes a vehicle state recognition unit configured to determine states of a vehicle using an acceleration value and an angular velocity value, a stopping state gravity vector calculation unit configured to calculate a stopping state gravity vector value, an accelerating state vehicle acceleration vector calculation unit configured to calculate a vehicle acceleration vector value, a vehicle pitch angle vector calculation unit configured to calculate a vehicle pitch angle vector value, and a vehicle pitch angle calculation unit configured to calculate a vehicle pitch angle using a corresponding vehicle pitch angle vector value.

Method including detecting low user dynamics by a first MEMS sensor is provided. A first sensor determines sampling rate value corresponding to the low user dynamics. The first sensor sampling rate value is less than a second sensor sampling rate value corresponding to high user dynamics. A sampling rate of a second MEMS sensor is adjusted to the first sensor sampling rate value.

A method to improve estimation and stabilization of heading in an inertial navigation system is provided. The method includes operating an inertial measurement unit oriented in a first orientation, forward-rotating the operational inertial measurement unit by a selected-rotation angle about a Z-body axis of the inertial navigation system, wherein the inertial measurement unit is oriented in a second orientation, operating the inertial measurement unit oriented in the second orientation, reverse-rotating the operational inertial measurement unit by the selected-rotation angle about the Z-body axis, wherein the inertial measurement unit is oriented in the first orientation, continuously receiving information indicative of an orientation of the inertial measurement unit at a rotational compensator, and continuously-rotationally compensating navigation module output at the rotational compensator, wherein output of the rotational compensator is independent of the rotating.

A vehicle monitoring system includes an accelerometer installed in the vehicle in an unknown orientation. The system infers the orientation of the accelerometer in the vehicle from the acceleration signals. The proposed method detects and corrects the orientation in two steps. In the first step, the gravity vector is used to estimate the orientation in the vertical plane. Then, based on the acceleration data collected during the vehicle movement, the heading of the vehicle is estimated and the orientation within the horizontal plane is corrected.

A system and associated methodology determine navigation parameters of a vehicle under varying center of gravity position and varying unknown gravitational forces. The system uses high precision accelerometers arranged in a plurality of configurations.

According to one aspect of an embodiment, an estimating apparatus includes a detector that detects accelerations. The estimating apparatus includes an identifying unit that identifies a gravity direction using an average of the accelerations that the detector detects in a certain state. The estimating apparatus includes an estimating unit that estimates a travel direction based on the gravity direction that the identifying unit identifies from the accelerations that the detector detects.

An inertial measurement system for a longitudinal projectile comprising: a first, roll gyro to be oriented substantially parallel to the longitudinal axis of the projectile; a second gyro and a third gyro with axes arranged with respect to the roll gyro such that they define a three dimensional coordinate system; a controller, arranged to: compute a current projectile attitude from the outputs of the first, second and third gyros, the computed attitude comprising a roll angle, a pitch angle and a yaw angle; compare the computed pitch and yaw angles with expected values for the pitch and yaw angles; calculate a roll angle error and a roll scale factor error based on the difference between the computed pitch and yaw angles and the expected pitch and yaw angles; and apply the calculated roll angle error and roll scale factor error to the output of the roll gyro.

A method for determining an orientation of a portable or mobile electronic device includes determining an orientation of the device using at least a first inertial motion sensor (e.g., a gyroscope) with which the portable electronic device is equipped. A correction factor is provided to the orientation of the electronic device using a feedback control signal based on motion data obtained from at least a second inertial motion sensor (e.g. an accelerometer) to reduce drift in motion data obtained from the first inertial sensor. Responsive to a loss of valid motion data from the first inertial motion sensor, a rate at which the correction factor is provided to the orientation of the portable electronic device is increased.

A device includes a memory and processing circuitry coupled to the memory. The processing circuitry, in operation: estimates an angular rate of change and determines a rotational versor based on the rotational data; and estimates a gravity vector based on the angular rate of change and the rotational versor. The processing circuitry generates a dynamic gravity vector based on the estimated gravity vector, a correction factor and an estimated error in estimated gravity vector. The processing circuitry estimates a linear acceleration and determines an acceleration versor based on the acceleration data, and determines the correction factor based on the linear acceleration. The processing circuitry estimates the error in the estimated gravity vector based on the acceleration versor.

A distance notification device includes a first and a second positional information acquiring units that acquire positional information on a user and peripheral users respectively at a predetermined time interval; a distance calculating unit that calculates respective distances between the user and the peripheral users based on the positional information; a distance determining unit that determines whether each of the distances is equal to or longer than a predetermined distance; a coordinate information calculating unit that calculates and update coordinate information on a meeting point based on the positional information; and a display that displays various images; wherein the display further notifies, by updating sequentially, the user of directional information toward the meeting point when a number of the peripheral users at a distance equal to or longer than the predetermined distance from the user is equal to or larger than a predetermined number.