Reference Guide - Alpine X209D Quick Reference Manual

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 75.
The following warning types are available:
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