General

PREAMBLE

Geographic location by GPS system

Note: GPS is the abbreviation of the term "Global Positioning System".

The GPS system consists of satellites distributed around the earth.

The satellites continuously transmit digital signals which travel at the speed of light, on 2 different frequencies.

The signals transmitted by the satellites are called "ephemerides".

At any time, the ephemerides allow the GPS receiver to know the position of all the satellites in the sky, as well as the time the message was sent.

The antenna receives these signals from inside the vehicle. The receiver built into the navigation computer deduces the respective distances separating it from each satellite.

The navigation computer thus deduces its position, and therefore that of the vehicle.

Geographic location by GPS system

Key:

• S1: satellite 1
• S2: satellite 2
• S3: satellite 3
• S4: satellite 4
• D1: distance between satellite 1 and the vehicle
• D2: distance between satellite 2 and the vehicle
• D3: distance between satellite 3 and the vehicle
• D4: distance between satellite 4 and the vehicle

Navigation assistance system

The on-board guidance system guides the driver to the destination entered, along a selected route. The on-board guidance system consists of the following components:

• a navigation computer incorporating a CD-ROM drive for map data,
• the vehicle's multifunction display (type C),
• a multiplexed radio,
• a GPS antenna,
• an infrared remote control,
• a last message recall control, integrated into the steering wheel switch module.

GENERAL BLOCK DIAGRAM

Navigation assistance system

Key:

Single arrow: wired link

Triple arrow: multiplexed link

DESCRIPTION OF SYSTEM COMPONENTS

Navigation computer

Navigation computer

The navigation computer calculates the optimal route and determines the path, then continuously compares the vehicle's journey with the selected instructions.

The navigation computer is located in the upper part of the glove box.

The navigation computer divides the route into several road segments and processes them as it goes.

A CD-ROM reader, built into the computer, reads a CD-ROM whose mapping is

produced and regularly updated by Navigation Technologies.

Multifunction display

The multifunction display is type C.

During guidance, the multifunction display shows different information depending on the manoeuvres to be carried out:

• Distance to the next manoeuvre,
• Next manoeuvre. When two manoeuvres are close together, the distance between them is shown,
• Next lane to take,
• Time,
• Outside temperature,
• Lane currently being used,
• Distance to the final destination.

Radio

Car radio

The radio amplifies the voice guidance instructions issued by the navigation system at line level.

Switching to the auxiliary input is controlled by the multifunction display.

GPS antenna

A GPS (Global Positioning System) antenna is integrated into the radio antenna. The antenna receives signals from the geostationary positioning satellites, and the navigation computer's gyrometer refines the position of the vehicle.

Infrared remote control

The remote control is stored in the centre console and is used to select the information contained in the various menus displayed.

Infrared remote control

The remote control is stored in the centre console and is used to select the information contained in the various menus displayed.

Warning: The satellite guidance system is operated by the infrared remote control only.

Repeat function

Steering wheel controls

Press the "A" button on the steering wheel switch module to have the last instruction repeated as a voice message.