Abstract: A method and apparatus for determining the attitude of an object is provided herein. The method for determining the attitude of the object comprises: receiving a gravity acceleration signal and a geomagnetic field signal, the gravity acceleration signal and the geomagnetic field signal changing with the attitude of the object accordingly; determining a gravity field representation in an object coordinate system according to the gravity acceleration signal, and determining a geomagnetic field representation in the object coordinate system according to the geomagnetic field signal; calculating a conversion parameter of coordinate system between to the object coordinate system and a terrestrial coordinate system according to the gravity field representation and the geomagnetic field representation in the object coordinate system; and determining the attitude of the object according to the conversion parameter of coordinate system.

Abstract: A method and apparatus for determining the attitude of an object is provided herein. The method for determining the attitude of the object comprises: receiving a gravity acceleration signal and a geomagnetic field signal, the gravity acceleration signal and the geomagnetic field signal changing with the attitude of the object accordingly; determining a gravity field representation in an object coordinate system according to the gravity acceleration signal, and determining a geomagnetic field representation in the object coordinate system according to the geomagnetic field signal; calculating a conversion parameter of coordinate system between to the object coordinate system and a terrestrial coordinate system according to the gravity field representation and the geomagnetic field representation in the object coordinate system; and determining the attitude of the object according to the conversion parameter of coordinate system.

Abstract: Apparatus and methods to compensate hard iron and soft iron magnetic interference in magnetic sensing devices are described. Hard and soft iron interference may be modeled using an ellipsoidal surface generated by a plurality of magnetic field measurements. A displacement of the ellipsoid from a reference frame origin corresponds to hard iron or permanent magnetic field interference. A shape and orientation of the ellipsoid corresponds to soft iron magnetic field interference. The ellipsoidal surface may be analyzed to obtain magnetic field compensation values for cancelling hard iron and soft iron interference.

Abstract: Apparatus and methods to compensate hard iron and soft iron magnetic interference in magnetic sensing devices are described. Hard and soft iron interference may be modeled using an ellipsoidal surface generated by a plurality of magnetic field measurements. A displacement of the ellipsoid from a reference frame origin corresponds to hard iron or permanent magnetic field interference. A shape and orientation of the ellipsoid corresponds to soft iron magnetic field interference. The ellipsoidal surface may be analyzed to obtain magnetic field compensation values for cancelling hard iron and soft iron interference.

Abstract: A magnetic sensor is calibrated by acquiring magnetic field measurements, fitting at least part of the plurality of magnetic field measurements to an ellipsoid model to obtain a coordinate of a center of the ellipsoid model, and determining a calibration offset according to the coordinate of the center of the ellipsoid model. The calibration offset is used to calibrate the magnetic sensor. The magnetic sensor itself obtains the magnetic field measurements. A processing device coupled to the magnetic sensor operates to process the magnetic field measurements is accordance with the ellipsoid mode and determine the calibration offset.

Abstract: The invention relates to a method of determining a zero-bias error of a gyroscope, an apparatus for determining a zero-bias error of a gyroscope and a system including the apparatus. The method includes the steps of: a. obtaining a set of outputs of the gyroscope; b. determining a dispersion degree of the outputs; c. determining whether the dispersion degree satisfies a predetermined condition and performing the step of d or e based upon a result of the determination; and d. determining an average of the outputs as the zero-bias error of the gyroscope when the dispersion degree satisfies the predetermined condition; or e. obtaining another set of outputs of the gyroscope and repeating performing the steps of b to c on the another set of outputs when the dispersion degree does not satisfy the predetermined condition.

Abstract: A method and apparatus for determining the attitude of an object is provided herein. The method for determining the attitude of the object comprises: receiving a gravity acceleration signal and a geomagnetic field signal, the gravity acceleration signal and the geomagnetic field signal changing with the attitude of the object accordingly; determining a gravity field representation in an object coordinate system according to the gravity acceleration signal, and determining a geomagnetic field representation in the object coordinate system according to the geomagnetic field signal; calculating a conversion parameter of coordinate system between to the object coordinate system and a terrestrial coordinate system according to the gravity field representation and the geomagnetic field representation in the object coordinate system; and determining the attitude of the object according to the conversion parameter of coordinate system.