“Trilateration” is used to determine an initial vehicle position for reference. Once this has been determined, mapping software stored on a DVD can be used to generate an overlay map and data for the driver on a display screen. As the vehicle moves the GPS continues to provide the necessary information to allow for plotting of position on the map.
Various DVD’s are available to cover the different continents.
Accurate and reliable navigation is still possible even when satellite signals become unavailable. This is achieved by using electronic sensors to monitor vehicle variables such as: Pitch, roll, yaw, road speed, steering angle, acceleration, and deceleration.
By using the information from these sensors, the navigation system is not continually and totally reliant on satellites.
During normal operation, the computer program compares vehicle position data derived from the satellites, and onboard sensor information, to ensure high levels of accuracy. In addition, ground based stations may be used in suitable locations, as an absolute reference point.
Satellite navigation features can include: Multiple languages and a choice of voice gender and destination and journey plotting, where the most suitable route is provided and deviation from the recommended route causes the system to provide an alternate route.
It can also include directional information provided with a combination of screen icons, maps and audible instructions; a self-learning route memory function; congestion avoidance, which can warn of the latest traffic bottlenecks and suggest alternative routes; various monitor color display settings; infra red remote control; trip computer; speed dependent setting; and telephone mute for sound systems.