1999 LAND ROVER DISCOVERY navigation update

NAVIGATION SYSTEM
87-2 DESCRIPTION AND OPERATION
Description
General
The navigation system provides audio and visual route guidance to help the driver reach a selected destination. The
system is an optional fit consisting of a Traffic Pro navigation computer and antenna, manufactured by Harman/
Becker Automotive Systems, which are fitted in place of the In Car Entertainment (ICE) head unit and antenna.
Compact Disc (CD) and radio functions are incorporated into the navigation computer.
The navigation system allows the driver to choose between the shortest and fastest routes between the vehicle's
current position and a selected destination, and to select a stopover point in the journey and a route that avoids
motorways, ferries and toll roads. Directions to Points Of Interest (POI) e.g. airports, hospitals, petrol stations etc,
either local, national or in another country, can also be selected. A traffic jam function enables the driver to request
diversion instructions, around an obstructed part of the selected route, during the journey. A Traffic Management
Control (TMC) function, currently only available in some European countries, monitors traffic broadcasts and
automatically selects an alternative route during the journey if the original route is effected by a traffic jam, accident
or road works etc.
The position of the vehicle is determined by the navigation computer using a combination of vehicle sensor inputs and
radio signals from the 24 Global Positioning System (GPS) satellites orbiting the earth. The position of the vehicle is
then plotted on a digitised map, loaded into the navigation computer from a CD-ROM, to determine the journey route
and provide the route guidance.
The GPS satellite signals are used for initial determination of the vehicle's position and periodic position updates. The
vehicle sensor inputs are used to monitor the vehicle's direction of travel and distance travelled between position
updates from the GPS satellite signals. The vehicle sensor inputs consist of:
lA vehicle speed signal from the ABS ECU, to monitor the distance travelled and for automatic volume control.
lA reverse gear signal from the selector and inhibitor switch of the automatic gearbox, or reverse gear switch of
the manual gearbox, to enable the navigation computer to differentiate between forward and rearward movement
of the vehicle.
lA gyro in the navigation computer, to monitor changes of direction, i.e. steering inputs.
The signal from each GPS satellite contains information about satellite position, almanac data and time (almanac data
is the current status of the satellite). Signals from between five and 11 of the GPS satellites can be received at a given
point on the earth's surface at any one time. The number and quality of separate GPS satellite signals received also
varies with vehicle location. In hilly or tree lined areas, built up areas with tall buildings, multi-storey car parks,
garages, tunnels, bridges and during heavy rain/thunderstorms, signal reception of some or all of the GPS satellites
will be poor or non existent.
A minimum of three separate GPS satellite signals are required for the navigation computer to calculate a three
dimensional (3D) positional fix. When only two signals are being received, the navigation computer will calculate a
less accurate two dimensional (2D) positional fix. The more widely dispersed that the GPS satellites are, the more
accurate the positional fix. The navigation computer can store information from a maximum of 12 GPS satellites at
any one time. When more than three signals are stored, the navigation computer selects the three most widely
dispersed signals for the position calculation.
GPS Antenna and diplexer unit
The GPS antenna is installed at the rear of the roof on the centreline. A diplexer unit on the underside of the GPS
antenna amplifies the radio signals received from the GPS satellites and transmits them through separate dedicated
co-axial cable to the navigation computer for processing.

NAVIGATION SYSTEM
DESCRIPTION AND OPERATION 87-7
Calibration
Calibration is required after initial installation or replacement of the navigation computer. It may also be necessary
after repairs to system wiring and if route navigation becomes inaccurate or fails to operate. If the navigation computer
contains an existing calibration, this must be deleted, using the garage menu, prior to running the new calibration
routine. The sensor inputs should also be checked before running the calibration routine.
Sensor Check
1Call up the SENSORS screen on the LCD:
lIf the navigation CD-ROM has not been installed before, press and hold multifunction button 1 then press
multifunction button 10.
lIf the navigation CD-ROM has been installed before, use the garage menu as detailed above.
2Drive the vehicle forwards a short distance at a speed greater than 2.5 mph (4 km/h) and ensure the road speed
counter on the SENSORS screen starts to increment.
3Select reverse gear and ensure the direction arrows on the SENSORS screen point rearwards.
4Ensure the GPS data on the SENSORS screen is displayed and updated.
NOTE: The GPS data will randomly display a GPS MODULE FAILURE message. This is not a fault condition, and
no action need be taken, provided the GPS data switches between the GPS MODULE FAILURE message and
actual GPS data.
5Exit the SENSORS screen:
lIf the navigation CD-ROM has not been installed before, press and hold multifunction button 1 then press
multifunction button 10.
lIf the navigation CD-ROM has been installed before, press the Nav button.

NAVIGATION SYSTEM
87-14 DESCRIPTION AND OPERATION
Description
General
Where fitted, the CARiN III and Trafficmaster system combines a satellite navigation system (CARiN III) with a real-
time traffic information system (Trafficmaster).
The satellite navigation system provides computer generated audible and visual route guidance information to enable
the driver to reach a desired destination. The system allows the driver to choose between road navigation and off-
road navigation, and to incorporate waypoints. Road navigation also allows the driver to choose between using minor
or major roads and the quickest or shortest route. Directions to hospitals, museums, monuments, hotels etc. are also
available. The computer uses map information stored on a CD-ROM to determine the best route for the journey and
provide the driver with details of directions and approaching junctions. The current position of the vehicle is
determined using a combination of vehicle sensor inputs and the Global Positioning System (GPS).
The Trafficmaster system displays live traffic flow information on the road navigation map screens. Traffic speed is
indicated on the maps by colour coded roads and arrows. The traffic flow information is relayed from a network of
sensors covering motorways and trunk roads. Data from the sensors is updated on a three minute cycle, 24 hours a
day, 365 days a year.
The navigation system consists of the following components:
lNavigation computer
lGPS antenna
lDisplay unit
lSwitch pack
lNavigation speaker
lTrafficmaster monitor ECU
lTrafficmaster antenna
Navigation Computer
The navigation computer is located in a bracket under the RH front seat, immediately behind the CD autochanger.
The navigation computer contains all the hardware and software required for control of the navigation system,
including the GPS receiver and a solid state piezo gyro. Using the gyro, and inputs from the GPS antenna and the
vehicle K bus, the navigation computer determines the vehicle’s current position, direction and speed.
The navigation computer also houses a CD-ROM drive. The drive is used to read map data from country specific CD’s
and also to load software into the computer. A button, adjacent to the CD slot, is provided to eject the CD from the
unit. If the 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. Access to the CD-ROM drive is from the rear of the RH front
seat.