Abstract: A method and a system is provided for inertial navigation applying an Extended Kalman Filter (EKF). Upon detecting degraded quality of inertial sensor data provided by an inertial sensor device and relating to at least one inertial axis, a noise estimate used by the EKF for the inertial sensor data is temporarily increased from a first noise estimate value to a second noise estimate value. The noise estimate concerns the at least one inertial axis or the inertial sensor associated with the inertial sensor data, and the second noise estimate value is greater than the first noise estimate value. Upon detecting normalization of quality of the at least one type of inertial sensor data, the temporarily increased noise estimate value used by the EKF calculation is reset back to the first noise estimate value after a predetermined delay period after detecting said normalization of quality.

Abstract: A method is disclosed for performing calculations for an inclinometer device, as is a digital circuitry for performing such calculations. The circuitry comprises an interface for receiving detection signals from a sensor device and a CORDIC unit for performing calculation of inclinometer output values characterizing a resultant vector. The CORDIC calculation unit is configured to perform a calculation for resolving the angle between a resultant vector and a programmable reference value using hyperbolic CORDIC calculation. Pre-rotation may be performed for a vector before hyperbolic CORDIC arctangent calculation phases.

Abstract: A method is disclosed for performing calculations for an inclinometer device, as is a digital circuitry for performing such calculations. The circuitry comprises an interface for receiving detection signals from a sensor device and a CORDIC unit for performing calculation of inclinometer output values characterizing a resultant vector. The CORDIC calculation unit is configured to perform a calculation for resolving the angle between a resultant vector and a programmable reference value using hyperbolic CORDIC calculation. Pre-rotation may be performed for a vector before hyperbolic CORDIC arctangent calculation phases.

Abstract: A device, system and method for monitoring blood pressure information of a user. A device is configured with at least one pressure sensor, a fastening element, and a processing component. In the method the pressure sensor is detachably attached to a position on the outer surface of a tissue of the user. The pressure sensor generates signal that vary according to deformations of the tissue in response to an arterial pressure wave expanding or contracting a blood vessel underlying the tissue. The signal is used to compute pulse wave parameters representing detected characteristics of the progressing arterial pressure wave of the user and blood pressure value of the user.