Range Rover P38
NAVIGATION SYSTEM
13
DESCRIPTION AND OPERATION
OPERATION
Display and Control Unit
Rotary Menu Controller
Turning the rotary menu controller one step
counter-clockwise sends a message to the navigation
computer. If the highlighted cursor is not at the top of
the list, then the navigation computer should respond
by moving the cursor up one position. If the cursor is
at the top of the list then there should be no action. If
the cursor is on a horizontal list the cursor should
move one step left.
Turning the rotary menu controller one step clockwise
sends a message to the navigation computer. If the
highlighted cursor is not at the bottom of the list, then
the navigation computer should respond by moving
the cursor down one position. If the cursor is at the
bottom of the list then there should be no action. If the
cursor is on a horizontal list the cursor should move
one step right.
Pressing and releasing the rotary menu controller
sends a message to the navigation computer. The
navigation computer should select the currently
highlighted menu item or icon and change the display
appropriately. If the LCD screen is switched off,
pressing and releasing the rotary menu controller will
switch the screen on.
Mute Key
Pressing and releasing the mute key causes the mute
status LED to be ’lit’. By having the mute function
enabled (LED on), this causes any audio instructions
given by the navigation system to be disabled. If the
mute function is already enabled (LED on), pressing
and releasing the mute key will cause it to be
disabled.
Repeat Key
Pressing and releasing the repeat key causes the last
audio instruction given by the navigation system to be
repeated through the vehicle speakers.
Re-Rte Key
Pressing and releasing the Re-Rte key, in road
navigation during guidance, causes the deviation
menu to overlay onto the screen, and the user is then
able to select a deviation distance between 0 and 6
miles. The system then calculates a new route once
the rotary menu controller has been pushed to accept
the deviation distance.
Menu key
Pressing and releasing the Menu key causes the main
menu screen to be displayed on the LCD. Pressing
and releasing the menu key while the screen is off
sends a message to the navigation computer. The
navigation computer should respond by turning the
LCD screen on and presenting the main menu.
Navigation Computer - Gyro Sensor
The piezo gyro sensor measures the motion of the
vehicle around its vertical axis using the Coriolis force.
The Coriolis force is a force which accelerates a
foreign body moving away from the rotational axis
against the direction of rotation of that axis.
In operation, a mass inside the sensor is excited to a
point where it begins to vibrate, similar to the principle
of a tuning fork. The vibrations travel perpendicular to
the rotational axis and cause continuous potential
charge of the mass in relation to the rotational axis.
The forces can be measured easily and are converted
into a yaw rate to calculate direction.