Owner's Manual

63
4 Reference guide
The following sections describe the different concepts and menu screens of Alpine Navigation
System.
4.1 Concepts
The following sections describe and explain navigation-related concepts.
4.1.1 2D/3D GPS reception
The GPS receiver uses satellite signals to calculate its (your) position and needs at least four signals
to give a three-dimensional position, including elevation. Because the satellites are moving and
because objects can block the signals, your GPS device might not receive four signals. If three
satellites are available, the receiver can calculate the horizontal GPS position but the accuracy is
lower and the GPS device does not give you elevation data; only 2D reception is possible.
Several factors have an impact on the deviation between your real position and the one given by the
GPS device. For example, signal delay in the ionosphere or reflecting objects near the GPS device
have a different and varying impact on how accurately the GPS device can calculate your position.
4.1.2 Natural and TTS voices
Natural voices are the traditional type of voice instructions. Every phrase that occurs in voice
guidance messages is recorded in a studio with a real person. The advantage of pre-recorded voice is
that it sounds really natural, but the range of instructions that can be given this way is limited.
Location-specific information such as street names cannot be announced.
TTS technology provides a machine-generated way to give voice instructions. The advantage of TTS
is that it can announce street names, traffic events, route summary, and traffic rules.
4.1.3 Road safety cameras and other proximity Alert Points
There is a special proximity warning for road safety cameras (like speed or red light cameras) and
other proximity Alert Points (like schools or railroad crossings). These Alert Points are not part of
Alpine Navigation System. You can download Alert points from alpine.naviextras.com or you can
upload points in a specific text file if needed.
There is a proximity warning for special locations such as schools or railroad crossings. You can add
your own Alert Points. See page 54.
The application can warn you when you approach road safety cameras like speed cameras or
dangerous areas like school zones or railroad crossings. You can set up the different alert types
individually in the Warnings settings, see page 78.
The following warning types are available:
• Audio warning: beeps are played (if the voice guidance language that you selected is a natural
voice) or the type of the alert can be announced (TTS voice) while you are approaching one of
these points, and an extra alert warns you if you exceed the given speed limit while
approaching.