Comtec ZDR-024CE - For Your Knowledge

7
Introduction
Introduction
For your knowledge
Ɣ What is GPS?
‘Global Positioning System’ means a system to measure a current position on the ground by
utilizing satellites of the Department of Defense of the United States.
Ɣ What is the ‘Michibiki’ quasi zenith satellite system (QZSS)?
The "Quasi Zenith Satellites System" is a system to measure the current position over Japan
using satellites of the Japan Aerospace Exploration Agency (JAXA). By receiving signals
from the Michibiki satellites, it has become possible to measure more accurate positions
over conventional GPS-only measurements, even within mountain areas or under high rising
buildings in the center of cities.
Ɣ What is GLONASS?
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positions on the ground by using the satellites of the Russian Space Force.
Ɣ Satellite data
This product computes and memorizes the motion trajectory of GPS satellites after receiving
signals successfully. This is to expedite processing to re-receive signals from the satellites in
cases where the product becomes unable to receive signals when running inside a tunnel,
etc. However, there may be rare cases when it becomes unable to receive the signals from
the GPS satellites for a long time.
Ɣ Receiving GPS satellite signals and car-mounted electronics
There are some occasions when the unit becomes unable to receive GPS satellite signals
when receiving (or setting to receive) UHF channel 56 by a car-mounted television or owing
to radio wave leakage from car-mounted electronics such as the main unit of car navigation
systems, terrestrial digital broadcasting tuners or satellite broadcasting receivers. In such a
case, you are requested to mount this product by keeping it away from other car-mounted
electronics devices to ensure there is no interference in receiving signals from GPS satellites.
Ɣ Regarding measurement errors of GPS
The GPS functions of this product may produce measurement errors by as much as 50 m
depending on conditions of the received signal.
Ɣ Regarding speed indications by GPS
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measured by the speedometer in your car, as the method employed to measure speed by
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There are some occasions when the product indicates a speed that is not 0 km/h even
during your car is completely stopped. However, please note that this is not a failure of the
product, as it is due to a measurement error in the GPS signal.
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This product displays the speed only in ‘km/h.’