Description
Navigation System
NOTE:
A = Hardwired; D = High Speed CAN bus; N = Medium Speed CAN bus; O = LIN bus; P = MOST ring; Q = GVIF; T = CoAxial
INTRODUCTION TO THE GLOBAL POSITIONING SYSTEM
The system used to calculate the current position of the vehicle is called the GPS (global positioning system). The system utilizes satellites which are owned by the United States Department of Defense. A total of 24 satellites circular orbit the earth every 12 hours at a height of 20,000 km (12500 miles), and between 5 and 11 of these satellites can be seen from a single point at any given time. The orbits are tilted to the earth's equator by 55 degrees to ensure coverage of polar regions. Each satellite transmits radio signals to provide information about the satellite position i.e. latitude, longitude, altitude, almanac data and an accurate time signal generated by an on-board atomic clock. Each satellite contains four atomic clocks.
The vehicle needs to receive data from at least four different satellites to give a three dimensional fix on its current position.
As the vehicle moves, this information is continually being updated. The computer determines which satellites are 'visible' to the system and their current position and relationship to each other. Using this information the computer can account for positional deviations of the satellites and compensate to enhance the accuracy of the navigation system.
The GPS (global positioning system) signal is also known as the PPS (precision positioning signal).
PPS (precision positioning signal) predictable accuracy is:
- 22 meters horizontal accuracy
- 27.7 meters vertical accuracy
- 200 nanoseconds time accuracy
The navigation system receives GPS (global positioning system) information via the GPS (global positioning system) antenna. The GPS (global positioning system) signals are used by the navigation computer to calculate the vehicles position. Once the driver has input a desired destination the navigation computer can calculate a route, based on the driver's pre-determined preferences or the default settings in the navigation computer.
The navigation system is accessed from the Touch-screen home menu.
Navigation is initiated by the driver inputting a destination. This can be achieved by:
- Entering an address using the Touch-screen
- Entering a post code
- Choosing a previous destination
- Choosing a point of interest from the map disc database
- Choosing the home location
- Choosing a memory stored location
The driver is then guided to the destination by a scrolling map display and voice guidance. The display can be varied by scale and display type.
In addition to the standard navigation system there are two market dependant systems that supply extra information to the navigation system and the driver. These are:
- TMC (traffic message channel) (Europe only)
- VICS (vehicle information and communication system) (Japan only)
The TMC (traffic message channel) is a function of the FM (frequency modulation)
RDS (radio data system). The system broadcasts real-time traffic and weather information. Data messages are received and decoded by the TMC (traffic message channel) integral receiver and processed by the navigation computer. TMC (traffic message channel) messages can be filtered by the navigation computer so that only those relevant to the current journey are displayed, allowing the navigation system to offer dynamic route guidance - alerting the driver of a problem on the planned route and calculating an alternative route to avoid the incident. All TMC (traffic message channel) events on the map can be viewed not just the ones on the calculated route.
TMC (traffic message channel) traffic information systems conform to a global standard that has been adopted by traffic data gatherers, information service providers, broadcasters and vehicle/receiver manufacturers.
All TMC (traffic message channel) receivers use the same list of event codes, while the location database (on the map disc) contains both a country-specific set of location codes for the strategic European road network.
TMC (traffic message channel) traffic data is currently broadcast in many European countries.
The VICS (vehicle information and communication system) is broadcast in the Japanese market.
The VICS (vehicle information and communication system) supplies information to enable the navigation computer to re-route the navigation guidance or to inform the vehicle driver of traffic conditions in the vehicles vicinity. Information is provided to the system through 3 routes:
- RF (radio frequency) transmission
- Infra-red transmission
- FM (frequency modulation) multiplex transmissions
The RF (radio frequency) transmissions are generally transmitted from road side beacons mainly on expressways. The information transmitted is as follows:
- Traffic congestion
- Travel time to next intersection
- Traffic conditions in surrounding areas and expressway turn offs
- Traffic accidents
- Speed limits
- Lane regulations
- Tire change
- Parking availability at expressway service areas and parking areas
Infra-Red transmissions are transmitted from road side beacons on major trunk roads. The information transmitted is:
- Traffic congestion and travel time
- Traffic accidents
- Breakdowns
- Road works restrictions
- Parking availability
FM (frequency modulation) transmissions are broadcast as part of the FM (frequency modulation) multiplex broadcasting system from NHK FM (frequency modulation) stations. Information transmitted is:
- Traffic congestion and travel time for wide areas
- Traffic accidents, road works, speed limits and lane restrictions for a wide area
- Parking availability information
The traffic data is split from the normal FM (frequency modulation) transmissions by the diversity antenna module.
Selection of 'Navigation' on the Touch-screen home menu and subsequent sub-menu selection sends a control request signal to the navigation computer on the MOST (media orientated systems transport) ring. The requested control information is processed by the navigation computer.
If voice guidance is operational the voice signal information is relayed from the navigation computer on the MOST (media orientated systems transport) ring to either the IAM (integrated audio unit) or Power Amplifier, dependant on equipment level, for output on the speaker system. The navigation audio output is through the front speakers whilst the background audio, for example radio or CD (compact disc), is played at a reduced volume on the rear speakers.
The GPS (global positioning system) signal is available to the navigation system at all times when the vehicle ignition is switched on.
Navigation user voice commands are made using the JaguarVoice system. The ICM (information control module) processes the analogue signal from the JaguarVoice switch into a digital signal. The digital signal is passed from the ICM (information control module) onto the MOST (media orientated systems transport) system to the JaguarVoice control unit which is integral with the navigation computer.
The navigation computer sends an instruction via the MOST (media orientated systems transport) ring to the IAM (integrated audio module) to turn on the microphone facility.
The microphone is hardwired to the IAM (integrated audio module). The spoken voice command signals are relayed from the IAM (integrated audio module) via the MOST (media orientated systems transport) ring to the navigation computer for processing.
The processed voice command is relayed from the navigation computer to the Touch-screen.
Traffic data from TMC (traffic message channel) or VICS (vehicle information and communication system) is processed by the navigation computer, distributed to the Touch-screen with any supporting voice instruction relayed through the MOST (media orientated systems transport) ring to either the IAM (integrated audio unit) or Power Amplifier, dependant on equipment level, for output on the speaker system.
A number of actions, when using the navigation voice system, are reinforced by messages appearing in the instrument cluster message center display. Information is relayed to the message center from the navigation computer on the MOST (media orientated systems transport) ring to the ICM (information control module).
The ICM (information control module) is the gateway from the MOST (media orientated systems transport) ring to the medium speed CAN (controller area network). The ICM (information control module) transfers the message center information onto the medium speed CAN (controller area network) which is received and processed for display on the instrument cluster message center.
NAVIGATION COMPUTER
The navigation computer is located in the left hand side of the luggage compartment.
The navigation computer incorporates the following:
- GPS (global positioning system) receiver
- VICS (vehicle information and communication system) receiver (Japan only)
- TMC (traffic message channel) receiver (Europe only)
- JaguarVoice control module
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 inputs from the ABS (anti-lock brake system) module, the GPS (global positioning system) antenna and the gyro sensor, the computer calculates the vehicle's current position, direction and speed.
The navigation computer houses the DVD (digital versatile disc) drive. The drive is used to read map data from region specific DVD (digital versatile disc)'s. The number of DVD (digital versatile disc)'s issued per region varies depending on the amount of information available. The regions are as follows:
- Europe (2 versions, Western Europe and Whole of Europe)
- NAS (North American specification)
- Japan, Middle East, Australia and South Africa
A button, located adjacent to the DVD (digital versatile disc) slot, is provided to eject the DVD (digital versatile disc) from the unit. Prior to ejecting the disc the slot protection has to be slid to the side. If the ignition is on, or the entertainment system is in 1-hour mode, one press of the button will eject the DVD (digital versatile disc).
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.
No configuration procedure is required if the navigation computer is replaced. There is no option to calibrate the navigation computer using the Jaguar approved diagnostic equipment; however in some regions a software download, contained in the DVD (digital versatile disc) disc, is required before the navigation system becomes operational.
MICROPHONE
A single microphone is used for hands-free operation using the JaguarVoice system. The microphone has an integrated noise suppression system for hands-free use. The microphone is a standard directional type and is located in the front roof overhead console. The microphone is hardwired to the IAM (integrated audio module). When replacing the microphone extra care must be taken to make sure it is fitted into its securing clips for correct positioning and orientation.
GPS Antenna
The GPS (global positioning system) antenna passes signals from the GPS (global positioning system) satellites to the navigation computer for processing. The antenna is located in the roof pod and is shared with the DAB (digital audio broadcasting) band L antenna or satellite radio antenna where fitted. The roof pod is located externally in a central position towards the rear of the roof.
The GPS (global positioning system) antenna is designed with 50 ohm output impedance. The navigation computer is fitted with 50 ohm fakra II connectors to ensure compatibility with the antenna. For optimum performance 50 ohm low loss coaxial cable is used between the antenna and navigation computer.
It is possible for the GPS (global positioning system) antenna to lose the signal from the GPS (global positioning system) satellites;
- In hilly or tree lined areas
- Built up areas with tall buildings
- In multi storey car parks
- In garages
- In tunnels
- On bridges
- During heavy rain or thunderstorms
When the signal is lost the navigation computer will continue to give guidance using memory mapped data from the DVD (digital versatile disc) map until the signal is restored.
TMC/VICS FM Antenna
Data messages for both TMC (traffic message channel) and VICS (vehicle information and communication system) are received through the FM (frequency modulation) antennas and diversity antenna module located in the heated rear window.
VICS Beacon Antenna (Japan Only)
The VICS (vehicle information and communication system) beacon antenna receives infra red and RF (radio frequency) traffic data signals from road side transmitters. The antenna is connected to the navigation computer which incorporates a VICS (vehicle information and communication system) receiver.
Touch Screen Display
The Touch-screen is the control interface for the following vehicle systems;
The screen is a touch sensitive 7 inch LCD (liquid crystal display) VGA screen containing 800 x 480 pixels in a 15:9 format. The screen processes its own video for system operation but receives the navigation graphics from the navigation computer.
Steering Wheel Controls
Additional control of the navigation system is available in the form of steering wheel mounted switches which are located on the left hand side of the steering wheel. 2 switches are used for navigation functions;
- Volume adjustment
- JaguarVoice control
JaguarVoice enables operation of several voice activated functions of the infotainment and climate control systems without the need to touch any controls manually. The following systems include JaguarVoice functionality;
- Navigation system
- Phone system
- Climate control system
- Vehicle display system
- Vehicle notepad
The 'notepad' facility allows voice notes to be recorded. Nametags for phone dialing and navigation locations allow the system to be personalized and there is a help and tutorial function to provide advice on using the system.
The system allows the vehicle user to concentrate fully on driving the vehicle, without any need to divert their eyes from the road ahead in order to check information read outs on the vehicle instrument panel information units. The voice control system also feeds back audible information to the vehicle user.
JaguarVoice is a key component of the navigation system, allowing hands free control when issuing navigation commands.
The system is controlled by the voice button on the left hand side of the steering wheel. Voice commands are picked up by a dedicated microphone. When giving a voice command audible feedback will be heard through the vehicle's audio speakers.
Efficient operation of JaguarVoice is reliant on the user understanding some of the following basic operating conditions;
- Face forwards, sitting in a normal driving position
- After pressing the voice button, always wait for the end of the tone before speaking.
- Speak naturally, as if you were talking to a passenger or on the phone without pausing between words
- When the system asks for more information, always wait for the end of the tone before responding
- Always say numbers correctly
- Excessive noise, for example while driving with windows open, may cause voice command mis-recognition. For example if it is too noisy to use the phone, it is likely that voice commands will not be recognized.
Most accents are understood without difficulty, but if the system does not recognize the command it will respond "SORRY" and allow two more attempts to say the command.
Voice feedback is given in the same language as the command recognition. It is possible to change the language of the speech control system.