Innalabs, Inc.

Isaak M Okon

Alain Renault

Jose Beitia

Dmitri V Simonenko

The invention relates to an inertial navigation system for a carrier comprising a core comprising gyroscopic sensors making it possible to determine the angular velocity thereof according to three axes defining a reference trihedron, two of the axes defining a reference plane and the third axis being at right angles to this plane. The device comprises command and control means making it possible to rotate the core about the third axis and to determine the direction of the geographic north on the basis of the information supplied by the gyroscopic sensors and by an accelerometer placed in the reference plane; the rotation of the core being performed with a period for which the value of the Allan variance of the stability error of the gyroscopic sensors is lower than a given value guaranteeing the accuracy with which the direction of the geographic north can be known.

Inertial navigation system with improved accuracy

The present invention is concerned with a method of calibrating a vibrating gyroscope. The method comprises exciting a vibration along an excitation axis of a resonant structure wherein the excitation axis is positioned at a first angular position, sensing the vibration of the resonant structure on a first sensing axis of the resonant structure while the excitation axis is positioned at the first angular position, generating a first sensing signal indicative of the sensed vibration of the resonant structure on the first sensing axis, rotating the excitation axis in a continuous manner around the resonant structure to a second angular position, sensing the vibration of the resonant structure on a second sensing axis of the resonant structure while the excitation axis is positioned at the second angular position, generating a second sensing signal indicative of the sensed vibration of the resonant structure on the second sensing axis and adding the first sensing signal to the second sensing signal in order to derive a bias of the gyroscope.

Method for calibrating vibratory gyroscope

The invention relates to gyroscopic instruments. The method for calibrating the scale factor of an angular velocity sensor or an axisymmetric vibratory gyroscope, which method uses a control amplitude signal, a control precessional signal CP and a control quadrature signal CQ for exciting the vibration of a resonator on a resonant frequency, involves a first step of pre-calibration which consists of measuring and recording an initial scale factor and the value of an initial control signal, and a second step of measuring the value of the current control signal and establishing a scale factor SF that is corrected on the basis of a proportional relationship involving the initial scale factor SF&#xb0;, the initial value of the control signal Y&#xb0; and the current value of the control signal Y&#xb0; according to the formula SF=SF&#xb0;Y/Y&#xb0;.

Calibration method for the scale factor of an axisymmetric vibratory gyroscope or gyrometer

An effective and precise method and system for compensation and measurement of a zero-bias in an axisymmetrical CVG (Coriolis Vibrating Gyroscope) is provided. Principal mode is driven according to an X-axis. Angular velocity is measured through Coriolis mode excitation along Y-axis. The sensitive axis of the gyroscope is reversed by 180 degrees by switching input and sense signals. Vibration is then driven along Y-axis and angular velocity is sensed along X-axis. On each position, after an arbitrary period of time, the gyroscope output is stored. Half-difference in outputs between two opposite position gives angular velocity and zero-bias effect is canceled. Half-sum in outputs between two opposite position gives the zero-bias error.

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New York, NY, United States of America

Isaak M Okon