Method of and apparatus for detecting angular velocity, method of and apparatus for detecting angle, navigation system, program storage device, and computer data signal embodied in carrier wave

DETAILED DESCRIPTION It is therefore an object of the present invention to provide a method of and an apparatus for detecting an angular velocity as well as a method of and an apparatus for detecting an angle, which can decrease the errors caused by the change by the start drift, the temperature drift or the like of the bias voltage of the angular velocity sensor such as a gyro, and further a navigation system equipped with the apparatus for detecting an angle, a program storage device and a computer data signal embodiment in a carrier wave, which allow a computer to function as the apparatus for detecting an angle or angular velocity.
The above object of the present invention can be achieved by a method of detecting an angular velocity provided with processes of: setting a bias voltage, as a standard voltage, which is an output voltage outputted from an angular velocity sensor in response to an angular velocity when a predetermined condition is satisfied as well as updating the standard voltage every time the predetermined condition is satisfied; calculating the angular velocity on the basis of the output voltage with using the set or updated standard voltage as a standard; storing time data, which indicate a time of setting or updating the standard voltage, in correspondence with standard voltage data, which indicate a value of the set or updated standard voltage; estimating a value of the bias voltage of the angular velocity sensor at each time between times of setting or updating the standard voltage, as a function of time, on the basis of a plurality of the stored standard voltage data and a plurality of the stored time data; and correcting the angular velocity calculated by the calculating process on the basis of a difference between a value of the standard voltage used in the calculating process and the estimated value of the bias voltage.
According to the method of detecting an angular velocity of the present invention, the bias voltage, which is the output voltage outputted from the angular velocity sensor such as a gyro, is firstly set as the standard voltage when such a predetermined condition that a movable body in various types such as an airplane, a rocket, a ship, a vehicle or the like, or a movable thing such as a robot, a video camera or the like, on which the angular velocity sensor is mounted, is stopping, is straightly advancing or the like is satisfied as an initial condition, for example