System for determining position of a vehicle includes an integral inertial measurement unit (IMU) including accelerometers and gyroscopes for providing raw data about movement of the vehicle and a correction unit coupled to the IMU and arranged to receive and/or derive positional corrections and the raw data from the IMU and generate accurate positional information about the vehicle based on the raw data and positional corrections. A navigation system is coupled to the correction unit and receives and acts upon the positional information of the vehicle provided by the correction unit. The IMU may be a MEMS-packaged IMU and integrated with the correction unit in combination with one another. A map database may be coupled to the navigation system which would receive information about a travel lane the vehicle is travelling on and could guide an operator of the vehicle based on the accurate positional information and travel lane information.