Discovery II
NAVIGATION SYSTEM
87-26
DESCRIPTION AND OPERATION
GPS Tracking Menu
Sensor Check
Selecting Sensor Test from the service mode menu causes the sensor check menu to be displayed. The sensor
check menu is used to confirm that all the input sensors are working. Some of the tests below involve driving the
vehicle for short distances. Before starting these tests ensure that an appropriate location, away from public roads
and obstructions, is chosen. The system-input sensors can be tested as follows:
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Wheel Sensors - When the vehicle is stationary the values in the wheel sensor boxes should both be zero. Drive
the vehicle for a short distance. While driving, a number should be displayed in the left wheel sensor box. The
value in the box should be proportional to the speed of the vehicle, and increase as the speed increases.
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GPS Satellites – Indicates the number of satellites being received
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GPS Status – Indicates the status of the GPS system by displaying one of the following messages:
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Position Known – The system has a current position fix. This indicates that the GPS system is functioning
normally.
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Satellite Contact – The system is tracking a number of satellites. This indicates that the system is working
correctly but does not have enough information to determine the position of the vehicle. Check that there is
nothing obstructing GPS antenna's 'view' of the sky. It may take several minutes for the GPS system to
acquire enough satellites to determine the vehicle's position (Position Known).
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Satellite Search – The system is searching for satellites. If this is displayed it may mean that there is a failure
in the GPS system. First check that the GPS antenna's 'view' of the sky is not blocked in any way. Check
harness connections between the navigation computer and the GPS antenna.
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GPS Error – There is a communication error between the GPS receiver and the navigation computer.
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GYRO – Drive the vehicle forwards, in a straight line and making left and right turns. When the vehicle is moving
in a straight line the direction arrow should be pointing to the top of the screen and the gyro value beside the
direction arrow should remain relatively constant. When the vehicle turns to the right, the direction arrow should
turn clockwise and the gyro value should increase. The size of the angle through which the direction icon turns
depends on the tightness of the turn. When the vehicle turns to the left, the direction arrow should turn anti-
clockwise and the gyro value should decrease.
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Direction of Travel – When the gear lever is in any position other than reverse, the display should show
Forwards. When reverse is selected, the display should change to Backwards.
Selecting <Return returns the system to the service mode menu.
M86 6073
GPS Tracking Info
1
2
3
4
Visible Satellites
Almanac
< Return
08
Yes
Functions
5.3
21
7.4
05
5.9
13
12.3
04
CH
PRN
S/N
CH
PRN
S/N
4.3
27
3.9
19
18.2
02
14.3
10
5
6
7
8