1. Location Technologies

2. Key Resources NASA GPS Latitude and Longitude www.nasa.gov www.gps.gov

3. Location Applications
Search
Location
Rendez-Vous
Navigation
Survey
Mapping

4. Location Technologies
Triangulation
Satellites
Global Positioning System (GPS)
SatPhones
Radar/LIDAR
Cellular Telephone
RFID/WiFi

5. Triangulation
Given the location of two known points, I can use geometry to calculate the location of a third point by measuring the angles between the known and third points.
Can use visual, electromagnetic or other means
Speed and direction can be gleaned from multiple observations

6. Triangulation

7. Triangulation Example
Suppose distress signals are received at Pittsburgh and Beaver Falls. Pittsburgh measures the angle of the signal as 70 degrees off North. Beaver Falls measures the angle of the signal as 30 degrees off North. Where is the distress signal coming from?
Location
Airport
Lat
Long
Pittsburgh
PIT
40.5
-80.22
Beaver Falls
BVI
40.75
-80.33

8. Triangulation Example
tan a = (P?Long - P1Long)/(P?Lat - P1Lat)
tan b = (P?Long - P2Long)/(P?Lat - P2Lat)
a = 70, tan a =
b = 30, tan b =.5773
(P?Lat ) = (P?Long )
(P?Lat ) = (P?Long )
P?Lat = (P?Long )/
P?Lat = P?Long
P?Lat = (P?Long )/
P?Lat = P?Long
1.744 P?Long = P?Long
P?Long =
P?Long =
P?Lat =

9. Antennas
Whip
Omni-directional
Dipole
Direction Sensitive

10. Antennas
Parabolic “Dish”
Directional
Aimed
Phased Array
Tuned

11. Satellites Orbital Classifications High Earth Orbit (HEO)
~22,300 miles
Orbital period ~ 1 day
Medium Earth Orbit (MEO)
Low Earth Orbit (LEO)
Hundreds of miles
Orbital period > 1 hour

12. Satellites High Earth Orbit (HEO) Communications
Geostationary/Geosynchronous/Synchronous
Stationary
22,300 miles Altitude
Circular Orbit
Equatorial Orbit
Orbital Period = 1 day

13. Communications Satellites
Voice
Data
Broadcast

14. Communication Satellite Technology
Ground Station
Converters
Amplifiers
Antenna
Dish – Parabola of rotation
Aiming - fixed
Azimuth – degrees off South
Elevation – degrees of horizontal

15. Telstar
Telstar I
07/10/1962
Telstar II
05/07/1963
AT&T - NASA

16. Tracking and Data Relay Satellite
TDRS 7 (G)
07/13/1995
NASA

17. Dish Antenna Aiming http://www.dishpointer.com/ Earth Location
Latitude: °
Longitude: °
Satellite Name: 45.8W TDRS 4
Altitude: 38614km
Elevation:  30.0°
Azimuth (true):  130.1°
Azimuth (mag.):  136.9° using Compass

18. Mobile Satellite Communications

19. Satellites Medium Earth Orbit (MEO) Space Shuttle
Miscellaneous Satellites

20. Low Earth Orbit Satellites
Altitude – hundreds of miles
Orbital periods – little more than an hour

21. Satellites Low Earth Orbit (LEO) GPS Satellites Spy Satellites
Survey Satellites
SatPhone Satellites

22. Spy/Survey Satellites
Polar orbit

23. NASA Arctic Ice Survey

24. XM WX SkyWatch

25. Spy Satellite Image

26. Spy Satellite Image

27. GPS U.S. Department of Defense (DOD) Originally - 24 satellites 1973
Overcame limitations of previous earth based navigation systems

28. GPS Now 32 satellites – spares Orbits
60 degrees apart
55 degrees inclination
Multiple satellites visible at any point on Earth at any time

29. GPS
A GPS receiver calculates its position by precisely timing the signals sent by multiple GPS satellites high above the Earth. Each satellite continually transmits messages containing identification, timing and location information.

30. Trimble GPS Unit

31. SatPhones Iridium Globalstar Thuraya 66 satellites Polar orbits
485 miles altitude
Globalstar
40 satellites
876 miles altitude
Thuraya

32. Iridium SatPhone

33. Cellular Telephone Network

34. Cell Phone GPS
HTC EVO

35. Radar Radio Detection and Ranging
Radio signals reflect off density masses (objects, clouds)
Sweeping or pulsing
Speed and direction are computable from multiple scans

36. Sweep image
Radar Scan

37. Lidar Light Detection and Ranging Uses Radiation in the light spectrum
Can detect finer differences
Lidar Image

38. Local/Indoor Location
WiFi
Bluetooth
RFID