class 17: introduction to navstar gps 19 march 2007
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Class 17: Introduction to NAVSTAR GPS
19 March 2007
Topics for today• Exam Review
• Deadline for article reviews 6 April 2007
• Some relevant history
• System components– Space– Ground– User
Brahe and Kepler
1546-1601
1571-1630
Kepler’s Laws1. Planetary orbits are elliptical with Sun as one focus.
2. Due to 1 planetary velocities vary. But sweep equal area in equal time.
3. The ratio of the squares of the revolutionary periods for two planets is equal to the ratio of the cubes of their semi-major axes.
Yet more graphics
Post WW-II Radio Navigation
• LORAN
• SHORAN
• OMEGA (ended 1997)
Federal Radionavigation Plan
• http://www.navcen.uscg.gov/pubs/frp2005/2005%20FRP%20WEB.pdf
Doppler
Early SatNav Systems
Transit on left, Timation on right
Radio Navigation
http://www.thespacereview.com/article/626/1
Six Planes/Five Slots
Broadcast Ephemeris Message
GPS Block IIR
Resources
• http://www.colorado.edu/geography/gcraft/notes/gps/gps_f.html
Observation File
SP3 Precise Orbit file
Position for TXSN
Between 1997 and May 2006 the position of this site changed by 0.143 m!
WHAT???????
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