Direction sensor having an earth magnetism sensor and a rate gyro sensor and navigation system having this direction sensor

A driving direction sensor of a vehicle outputting a compensated direction, comprising:

• an earth magnetism sensor detecting a forward angle, forming the detected forward angle relative to magnetic north of earth, and outputting a first driving direction calculated from said detected forward angle;
• a rate gyro sensor, detecting a rotating speed, forming the detected rotating speed, calculating a rotated angle from the detected rotating speed, and outputting a second driving direction obtained by adding said rotated angle to a reference direction;
• and
• direction compensating means for calculating the compensated direction using a weighted mean process of said first driving direction from said earth magnetism sensor and said second driving direction from said rate gyro sensor, and for setting said compensated direction to said reference direction of said rate gyro sensor, wherein:
• a weighted mean ratio of said weighted mean process changes according to one of temperature of said rate gyro sensor and environment temperature.

A navigation system of a vehicle providing a locating position on a map, comprising:

• an earth magnetism sensor detecting a forward angle, forming the detected forward angle relative to magnetic north of earth, and outputting a first driving direction calculated from said detected forward angle;
• a rate gyro sensor, detecting a rotating speed, forming the detected rotating speed, calculating a rotated angle from the detected rotating speed, and outputting a second driving direction, obtained by adding said rotated angle to a reference direction;
• direction compensating means for calculating a compensated direction, using a calculating process receiving said first driving direction and said second driving direction;
• a driving distance sensor detecting a driving distance;
• map storing means for storing map information;
• locating position calculating means for calculating the locating position on said road map using said compensated direction received from said direction compensating means, said driving distance received from said driving distance sensor and said map information received from said map storing means;
• disturbance data storing means for storing distribution information indicating a magnetic disturbance having an intensity to an earth magnetism in a form corresponding to said map;
• and
• ratio changing means for detecting the intensity of the magnetic disturbance at said locating position received from said disturbance data storing means, and for ratio changing the calculating process used for calculating said compensated direction.