The present invention discloses an improved vehicular inertial guidance
navigation system, a.k.a. a dead reckoning system for navigation of a
vehicle. The inertial guidance navigation system which may be used alone
or in combination with other position determination means, such as GPS and
map databases, to determine the location of a vehicle. The dead reckoning
system has several advantages over existing systems. First, it can be
easily mounted to the chassis of any vehicle. Second, it does not require
any interface with existing sensors on the vehicle. Third, the system
contains logic for removing errors in the position and heading
determinations, brought about by angulation/rotation of the chassis and
inertial guidance sensors, brought about by inclination or tilt of the
chassis, with respect to an inertial/quasi-inertial frame of reference,
such as the earth. The inertial guidance system includes: an inertial
guidance sensor, a translation unit, and a logic unit. The inertial
guidance sensor is suitable for coupling to the vehicle. The inertial
guidance sensor senses motion of the vehicle in a non-inertial frame of
reference and forming a sensor signal corresponding thereto. The
translation unit is coupled to receive the sensor signal formed by the
inertial guidance sensor. The translation unit translates the sensor
signal into a quasi-inertial frame of reference and forms a translated
signal corresponding thereto. The logic unit receives the translated
signal formed by the translation unit and converts converting the
translated signal into an estimated position and heading of the vehicle.