Pioneer AVIC F900BT Manuel d'utilisateur télécharger pdf (Page 142)

Positioning technology

AVIC-F900BT accurately measures your cur-

rent location by combining the positioning by

GPS and by “Dead Reckoning”.

AVIC-F700BT accurately measures your cur-

rent location by the GPS positioning.

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.

Positioning by “Dead Reckoning”

The built-in sensor in the navigation system

also calculates your position. The current loca-

tion is measured by detecting driving distance

with the speed pulse, the turning direction

with the “Gyrosensor” and inclination of the

road with the “G sensor”.

The built-in sensor can even calculate

changes of altitude, and corrects for discre-

pancies in the distance travelled caused by

driving along winding roads or up slopes.

If you use AVIC-F900BT with connecting the

speed pulse, the system will become more ac-

curate than no connection of speed pulse. So

you connect the speed pulse without fail to get

the accuracy of positioning.

p The position of the speed detection circuit

vary depending on the vehicle model. For

details, consult your authorised Pioneer

dealer or an installation professional.

p Some types of vehicles may not output a

speed signal while driving at just a few kilo-

metres per hour. In such a case, the current

location of your vehicle may not be dis-

played correctly while in a traffic jam or in

a vehicle park.

How do GPS and “Dead

Reckoning” work together?

For maximum accuracy, your navigation sys-

tem continually compares GPS data with your

estimated position as calculated from the data

of built-in sensor. However, if only the data

from the built-in sensor is available for a long

period, positioning errors are gradually com-

pounded until the estimated position becomes

unreliable. For this reason, whenever GPS sig-

nals are available, they are matched with the

data of the built-in sensor and used to correct

it for improved accuracy.

p If you use chains on your wheels for winter

driving or put on the spare wheel, errors

may suddenly increase because of differ-

ence in wheel diameter. In such case,

pressing RESET button initialise the sensor

status and it may recover the accuracy to

normal condition.

Appendix

Engb

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Appendix

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