Geely EC715 2009, Workshop Manual

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11.3.3.3 Self-Navigation
When the vehicle is traveling to an underground tunnel,
between high-rise buildings, under highway bridges, it may not
receive GPS satellite signals, the system can automatically
enter the self-navigation mode. At this point the vehicle speed
sensor detects the vehicle, the vehicle microprocessor
calculates the distance. Gyro sensor directly detects the
direction change and moving forward status. For example,
when the vehicle is traveling in the ditch like Hill Road, round
shape bridge, skidding on snow, all these curves cause
positioning errors. Only the gyro sensor and microprocessor
calculations can get the correct vehicle location. However, the
positioning accuracy is far below the GPS positioning
accuracy.
11.3.3.4 Map Matching Techniques
Microprocessor electronic map is identified by the node-based
data.
FE11-5204b
There are discrepancies between the GPS satellite navigation
and self-navigation devices detected vehicle location and
direction and the actual driving route. To correct these errors,
the map-matching techniques are used. The microprocessor
correct the errors electronic map errors and automatically
adjust.
Map database stores roads, road maps and urban transport
map. Before driving, input the city, streets, place names, etc.
through the input interface. Through satellite signals systems,
the processor determines the direction and the best route
according to vehicle speed sensors, gyro sensors measured
data. During driving, driver can observe the screen to get the
current location. Display can also show the distance remaining
to reach the destination. At the same time prompts the related
information through audio voice output to the driver.
Body Electric Navigation 11-41
EC718/EC718RV EC715/EC715RV 10/2009