Pioneer U310 Manuel d'opérations télécharger pdf (Page 119)

Positioning technology

Positioning by GPS

The Global Positioning System (GPS) uses a

network of satellites orbiting the Earth. Each

of the satellites, which orbit at a height of

21 000 km, continually broadcasts radio sig-

nals giving time and position information. This

ensures that signals from at least three can be

picked up from any open area on the earth’s

surface.

The accuracy of the GPS information depends

on how good the reception is. When the sig-

nals are strong and reception is good, GPS

can determine latitude, longitude and altitude

for accurate positioning in three dimensions.

But if signal quality is poor, only two dimen-

sions, latitude and longitude, can be obtained

and positioning errors are somewhat greater.

Map matching

As mentioned, the positioning systems used

by this navigation system are susceptible to

certain errors. Their calculations may, on occa-

sion, place you in a location on the map where

no road exists. In this situation, the processing

system understands that vehicles travel only

on roads, and can correct your position by ad-

justing it to a nearby road. This is called map

matching.

With map matching

Without map matching

Handling large errors

Positioning errors are kept to a minimum by

combining GPS and map matching. However,

in some situations, these functions may not

work properly, and the error may become big-

ger.

Appendix

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Appendix

Appendix

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