Acura 3.5 RL Manual page 1300

Navigation Unit
The navigation unit calculates the vehicle position and guides you to the destination. The unit performs map matching
correction, GPS correction, and distance tuning. It also controls the menu functions and the DVD-ROM drive, and inter-
prets voice commands. With control of all these items, the navigation unit makes the navigation picture signal, then it
transmits the signal to the display unit and audio driving instructions to the audio unit.
Calculation of Vehicle Position
The navigation unit calculates the vehicle position (the driving direction and the current position) by receiving the direc-
tional change signals from the yaw rate sensor and the travel distance signals from the vehicle speed pulse (VSP) sensor.
Map Matching Tuning
The map matching tuning is accomplished by indicating the vehicle position on the roads on the map. The map data
transmitted from the DVD-ROM is checked against the vehicle position data, and the vehicle position is indicated on the
nearest road. Map matching tuning does not occur when the vehicle travels on a road not shown on the map, or when the
vehicle position is far away from a road on the map.
GPS Tuning
The GPS tuning is accomplished by indicating the vehicle position as the GPS's vehicle position. The navigation unit com-
pares its calculated vehicle position data with the GPS vehicle position data. If there is a large difference between the two,
the indicated vehicle position is adjusted to the GPS vehicle position.
Distance Tuning
The distance tuning reduces the difference between the travel distance signal from the VSP and the distance data on the
map. The navigation unit compares its calculated vehicle position data with the GPS vehicle position data. The navigation
unit then decreases the tuning value when the vehicle position is always ahead of the GPS vehicle position, and it increas-
es the tuning value when the vehicle position is always behind the GPS vehicle position.
Route Guidance
The navigation unit can calculate different routes to a selected destination. You have five options:
• Direct Route - Calculate a route that is the most direct and will take the least tome.
• Easy Route - Calcute a route that minimizes the number of turns needed.
• Minimize Freeways - Calculate a route that avoids freeway travel. If that is not possible, keep the amount of freeway
travel to a minimum.
• Minimize Toll Roads - Calculate a route that avoids, or minimizes travel on toll roads.
• Maximize Freeways - Calculate a route that uses freeways as much as possible.
Audio Guidance
The navigation unit transmits audio driving instructions before entering an intersection or passing a junction.
The audio instructions come through the audio unit and the front speakers.
The front speakers are muted whenever the navigation system is giving guidance commands, and all of the speakers
when the voice control system is being used. When using OnStar, both the audio system and the navigation system are
muted, and the voice control switch (TALK and BACK buttons) is disabled.
DVD-ROM
The map data (including all scale rates) is stored in the DVD-ROM. The map date includes:
• Road distances, road widths, speed limits, traffic regulations, passing time at junction, distances to junctions, and the
driving instructions for audio guidance.
• Latitude and longitude GPS.