2. Global Positioning System (GPS)

3. 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

4. 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

5. need at least 3 satellites ‘in range’ –line of sight uses ‘trilateration’ to determine position GPS

6. 6 satellites used (green) 1 low power signal (red - going out of range?) GPS

7. 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

9. add map data to system plot current position on map GPS plotters

12. GPS PDA + GPS card

13. 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

14. 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

15. 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

16. 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

17. Satellite Navigation Communicating with unit:

18. Satellite Navigation Communicating with unit:

19. Satellite Navigation Communicating with unit:

20. Satellite Navigation Communicating with unit:

21. Satellite Navigation Communicating with unit:

22. Satellite Navigation Communicating with user: Visual Display Unit (screen) showing turns on map

23. Satellite Navigation Communicating with user: Visual Display Unit (screen) showing turns on map

24. Satellite Navigation Communicating with user: Visual Display Unit (screen) showing turns on map

25. Satellite Navigation Communicating with user: Visual Display Unit (screen) showing turns on map audio communication - voice synthesis

26. Satellite Navigation Communicating with user: Visual Display Unit (screen) showing turns on map audio communication - voice synthesis

27. Satellite Navigation Communicating with user: Visual Display Unit (screen) showing turns on map audio communication - voice synthesis

28. Satellite Navigation Communicating with user: Visual Display Unit (screen) showing turns on map audio communication - voice synthesis head up display (HUD) available

29. Satellite Navigation Head Up Display:

30. Satellite Navigation Head Up Display:

31. Satellite Navigation Head Up Display (night vision):

32. Satellite Navigation Head Up Display (night vision):