01-01-2013, 12:19 PM
Introduction to the Global Positioning System
What is the GPS?
Orbiting navigational satellites
Transmit position and time data
Handheld receivers calculate
latitude
longitude
altitude
velocity
Developed by Department of Defense
Components of the System
Space segment
24 satellite vehicles
Six orbital planes
Inclined 55o with respect to equator
Orbits separated by 60o
20,200 km elevation above Earth
Orbital period of 11 hr 55 min
Five to eight satellites visible from any point on Earth
Block I Satellite Vehicle
GPS Satellite Vehicle
Weight
2370 pounds
Height
16.25 feet
Width
38.025 feet including wing span
Design life—10 years
Block IIR satellite vehicle assembly at Lockheed Martin, Valley Forge, PA
Components of the System
Ground control segment
Master control station
Schreiver AFB, Colorado
Five monitor stations
Three ground antennas
Backup control system
How does GPS work?
Satellite ranging
Satellite locations
Satellite to user distance
Need four satellites to determine position
Distance measurement
Radio signal traveling at speed of light
Measure time from satellite to user
Low-tech simulation
Application of GPS Technology
Location - determining a basic position
Navigation - getting from one location to another
Tracking - monitoring the movement of people and things
Mapping - creating maps of the world
Timing - bringing precise timing to the world