navigation update TOYOTA SIENNA 2007 Service Repair Manual

NAVIGATION – NAVIGATION SYSTEMNS–5
NS
Operation Description
Vehicle Position CalculationThe radio and navigation assembly calculates the current vehicle
position (direction and current position) using the direction deviation
signal from the gyro sensor and the running distance signal from the
vehicle speed sensor and creates the driving route.
Map Display ProcessingThe radio and navigation assembly displays the vehicle track on the
map by processing the vehicle position data, vehicle running track,
and map data from the map disc.
Map MatchingThe map data from the map disc is compared to the vehicle position
and running track data. Then, the vehicle position is matched with the
nearest road.
GPS CorrectionThe vehicle position is matched to the position measured by GPS.
Then, the measurement position data from the GPS unit is compared
with the vehicle position and running track data. If the position is
widely different, the GPS measurement position is used.
Distance CorrectionThe running distance signal from the vehicle speed sensor includes
the error caused by tire wear and slippage between the tires and road
surface. Distance correction is performed to account for this. The
radio and navigation assembly automatically offsets the running
distance signal to make up for the difference between it and the
distance data of the map. The offset is automatically updated.
I100028E07