Alpine ICS-X7 Owner's Manual page 50

When there is a steep upward slope behind the car
(example)
<Screen>
Distance guidance marks
<Situation of the car>
The distance guidance mark represents the distance to a
flat road surface. Therefore in the case of an upward
slope behind the car, the distance guides are displayed
closer to the rear bumper than the actual distance. For
example, if there is an obstacle on the upward slope, it
may appear farther away than its actual position.
Also, an error may occur between the guidance and the
actual path of the car on the road surface.
50
-EN
Actual distances
Error Error
When there is a steep downward slope behind the
car (example)
<Screen>
<Situation of the car>
In the case of a downward slope behind the car, the
distance guides are displayed farther from the rear
bumper than the actual distance.
If there is an obstacle on the downward slope, it seems
closer than its actual position.
Also, an error may occur between the guidance and the
actual path of the car on the road surface.
Error Error