Global Positioning System

spectacularscarecrowAI and Robotics

Nov 17, 2013 (3 years and 4 months ago)

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Global Positioning System

(GPS)

Learning Objectives:

By the end of this topic you should be able to:



describe how satellite communications systems are
used in
global positioning
,



describe the
advantages

and
disadvantages

of using
satellites for global positioning


24 satellites in Low Earth Orbit


put in place by US military


available to anyone with a receiver


used in marine, aviation & terrestrial navigation

GPS


need at least 3 satellites ‘in range’


line of sight


uses ‘trilateration’ to determine position

GPS


6 satellites used (green)


1 low power signal (red
-

going out of range?)

GPS


inexpensive,


from <£100


can be a handheld device


portable


walking, cycling ….


can be used in remote locations


text readout of latitude & longitude


built
-
in software can calculate speed and direction

GPS receivers

GPS receivers


add map data to system


plot current position on map

GPS plotters

GPS plotters

GPS plotters

GPS

PDA + GPS card

Satellite Navigation


requires Global Positioning System (GPS)


at least three satellites required for fix


radio signal, line of sight


accurate to within a kilometre


use of receiver on vehicle to decode the signals


current position shown on a screen map


overlay other data:


points of interest (POI) e.g. petrol stations, hotels


traffic cameras


roadworks, delays
-

recalculate & display new route

Advantages of GPS/Sat Nav


accuracy can be as good as 30cm


can find lost people from lat/long or position


no need to use map


concentrate on driving


save time by not planning journeys


software does it automatically


new route calculated if driver makes an error


maps can be updated from the Internet

Disadvantages of GPS/Satnav


requires line of sight access to satellites


no use in a building or in tunnels


atmospheric conditions can affect accuracy


system may not have up
-
to
-
date maps


driver given incorrect instructions


over reliance on satnav may mean loss of map skills


may get lost if system fails


operating system while driving is dangerous


destinations may not be recognised by system

Satellite Navigation

Communicating with unit:


push buttons to set instructions,


voice to dictate instructions (voice recognition),


keyboard to type instructions,


use of predictive text,


touch screen,


joystick,


CDROM, DVD or mobile phone to input maps

Satellite Navigation

Communicating with unit:


Satellite Navigation

Communicating with unit:


Satellite Navigation

Communicating with unit:


Satellite Navigation

Communicating with unit:


Satellite Navigation

Communicating with unit:


Satellite Navigation

Communicating with user:


Visual Display Unit (screen) showing turns on map

Satellite Navigation

Communicating with user:


Visual Display Unit (screen) showing turns on map

Satellite Navigation

Communicating with user:


Visual Display Unit (screen) showing turns on map

Satellite Navigation

Communicating with user:


Visual Display Unit (screen) showing turns on map


audio communication
-

voice synthesis

Satellite Navigation

Communicating with user:


Visual Display Unit (screen) showing turns on map


audio communication
-

voice synthesis

Satellite Navigation

Communicating with user:


Visual Display Unit (screen) showing turns on map


audio communication
-

voice synthesis

Satellite Navigation

Communicating with user:


Visual Display Unit (screen) showing turns on map


audio communication
-

voice synthesis


head up display (HUD) available

Satellite Navigation

Head Up Display:


Satellite Navigation

Head Up Display:


Satellite Navigation

Head Up Display (night vision):


Satellite Navigation

Head Up Display (night vision):