Navigation apparatus and navigation information calculation method

A navigation information calculation method comprising:

• a travel direction acceleration calculation step of calculating a mobile object's acceleration in the direction of the mobile object's motion, based on the mobile object's speed calculated from information received from a satellite;
• a lateral acceleration calculation step of calculating lateral acceleration whose direction is perpendicular to the mobile object's motion, based on the mobile object's speed and direction calculated from information received from the satellite;
• an observation step of observing motion acceleration of the mobile object and gravity acceleration by using an acceleration sensor;
• an altitude difference calculation step of calculating an altitude difference of road based on an atmospheric pressure value supplied from a barometric sensor;
• an inclination calculation step of calculating an inclination angle of the road in the direction of the motion, based on the altitude difference calculated by the altitude difference calculation step and a travel distance corresponding to the mobile object's speed;
• and
• an attachment angle calculation step of calculating an attachment angle of the acceleration sensor with respect to the mobile object by using a multidimensional function formula including the acceleration in the direction of the motion, the lateral acceleration, values observed by the acceleration sensor and the inclination angle, the observed values including the motion acceleration and the gravity acceleration.

A navigation apparatus comprising:

• a travel direction acceleration calculation section that calculates a mobile object's acceleration in the direction of the mobile object's motion, based on the mobile object's speed calculated from information received from a satellite;
• a lateral acceleration calculation section that calculates lateral acceleration whose direction is perpendicular to the mobile object's motion, based on the mobile object's speed and direction calculated from information received from the satellite;
• an acceleration sensor that observes motion acceleration of the mobile object and gravity acceleration;
• an altitude difference calculation section that calculates an altitude difference of road based on an atmospheric pressure value supplied from a barometric sensor;
• an inclination calculation section that calculates an inclination angle of the road in the direction of the motion, based on the altitude difference and a travel distance corresponding to the mobile object's speed;
• and
• an attachment angle calculation section that calculates an attachment angle of the acceleration sensor with respect to the mobile object by using a multidimensional function formula including the acceleration in the direction of the motion, the lateral acceleration, values observed by the acceleration sensor and the inclination angle, the observed values including the motion acceleration and the gravity acceleration.