Audi A8 2019 Service Training page 99

Laser Distance Regulation Control Module J1122
Installation location
J1122 is used in the Audi A8 to implement complex driver
assistance functions. It is installed in the center of the
bumper under the license plate carrier.
Function
The general functional principle is similar to that of a radar
sensor: instead of radar waves, the laser scanner emits
laser beams which are reflected when they impinge on the
surfaces of other objects.
It is possible to measure the distance to an object by deter-
mining the elapsed time from emittance to reception of the
reflected radiation components. The type of object is also
determined. The reflection received by the scanner is made
up of a multiplicity of dots known as dot clouds. The con-
tours of the object are more well-defined than those
acquired with radar technology, making it easier to classify
objects.
The horizontal detection zone covers an angular range of
about 145°. The range is approximately 87.4 yd (80 m) on
average, and object recognition is possible from a distance
of 3.9 in (10 cm).
The laser scanner complements the long-range radar.
Although the radar system has a much longer range (273.4
yd [250 m]), the coverage angle of approximately 35° is
much less than that of the laser scanner.
Calibration
The installation position of the laser scanner can be
adjusted and is subject to tolerances. Provision has been
made for vertical adjustment only.
The adjustment is similar to that of the ACC and is carried
out using a new optical target (calibration board).
ACC unit
To accommodate the laser scanner, an ACC unit is located
on the right-hand side of the 2019 A8. The laser scanner
assumes the function of the second ACC unit. ACC is no
longer available as a separate option in the A8, but rather is
an optional feature of "Adaptive Cruise Assist" (ACA) in the
driver assist package. The 4th generation ACC system is
identical in design and basic functions to the ACC of the
2017 Audi Q7.
Laser Distance Regulation
Control Module
J1122
Object contours are recognizable in detail
Laser scanner calibration board VAS 6430/12
4th generation ACC unit
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662_189
662_190
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