1. The Global Positioning System and Embedded Receiver Applications
Noah Wardrip
CSE237A

2. Agenda Introduction Current Status and Operation of GPS
Future Direction of GPS
Embedded Receiver Applications

3. Introduction Worldwide satellite positioning system
24 hours/day, all weather, receive-only
GPS Military in Origin
Wide-scale civilian adoption
Comprised of three components:
Space
Control
User
Focus: Empower embedded receiver designer with current information

4. Current Status and Operation
Currently 31 Block II satellites in orbit
6 orbital planes – Always ≥6 satellites in view
12,500 miles – Medium Earth Orbit
12 monitoring stations around the world
Control and update with timing and orbit info

5. Current Status and Operation
3 codes on 2 carriers
C/A code – course acquisition for civilian use
P/Y code – precision code (encrypted)
M code – military code with packet data
Codes modulated using CDMA technique
Receivers use trilateration to calculate position

6. Current Status and Operation
GPS has several drawbacks
Line-of-sight to satellite is required
Data rate low causing long first fixes
Several sources of error in measurement
Clock offset
Imperfect orbit information
Ionospheric effects
Receiver noise
Augmentation services developed
Require special receiver support

7. Future Direction of GPS
Block III Satellites will provide increased reliability and accuracy through:
Additional civilian signals
Additional military signals
Stronger “Safety-of-life” signal for aircraft
Compatibility with Galileo

8. Embedded Receiver Applications
Hardware improvements are helping miniaturize receivers
Types of receivers include:
Civilian
Surveying
Fixed installation
Military
All share similar building blocks

9. Embedded Receiver Applications
Examples include
Cell phones – location based services
Cameras – instant fix needed
Time-critical activities – networks
Non-GPS satellite orbit correction

10. Conclusion Possibilities with embedded GPS are limitless
Successful receiver design requires understanding entire system
Now more than ever are innovative solutions to GPS limitations
Questions?