Navigation Computer

Fig 1: Identifying Navigation Computer (1 Of 3)

Courtesy of LAND ROVER NORTH AMERICA, INC.

The navigation computer is located in the left hand side of the luggage compartment. The computer is the main component in the navigation system and receives inputs from the Body Control Unit (BCU) and the GPS antenna. The navigation computer contains a solid state piezo gyro which measures the motion of the vehicle around its vertical axis. The gyro operates on the principle known as the Coriolis force. The Coriolis force is the force that appears to accelerate a body moving away from its rotational axis against the direction of rotation of the axis.

Using the inputs from the BCU, the GPS antenna and the gyro sensor, the computer calculates the vehicle's current position, direction and speed.

The navigation computer also houses the CD-ROM drive. The drive is used to read map data from country specific CD's and also to load updated software into the computer. A button, located adjacent to the CD slot, is provided to eject the CD from the unit. If ignition is on, one press of the button will eject the CD. If the ignition is off, two presses are required, one to wake up the system and the second to eject the CD.

Previous Range Rover navigation systems used a separate navigation receiver, this version integrates the receiver within the navigation computer. The GPS receiver receives information from between 1 and 8 satellites at any one time. This information is received from the GPS antenna. The built in GPS receiver the following functions:

Calculation of position (i.e. Latitude, longitude and height), direction and speed
Collection and storage of almanac data
Real-time clock.

The navigation computer uses non-volatile memory to store settings and configuration information when it is powered down. This process takes place just before the computer turns off and occurs approximately one minute after all K-Bus activity has ceased. Once the power down sequence has been completed, the red LED on the front of the unit is extinguished.

CAUTION: If the unit is disconnected before the LED goes out the computer could fail to complete its data storage. This will cause the unit to become unusable and it must be replaced.

For the Japanese market the navigation computer is a different component. Although it looks identical the unit houses a DVD drive and the internal receiver is replaced by an external one. The system also has extra components for the VICS system (a receiver and an antenna). The VICS system receiver allows the vehicle to receive information about traffic conditions from roadside transmitters and adjust the navigation instructions accordingly. The VICS information is received by both a radio link and an infra red link. For this reason the antenna is located behind the rear view mirror on the inside of the windscreen.