GPS THE GLOBAL POSITIONING SYSTEM

What is GPS? GPS is a satellite-based radio navigation system that allows anyone anywhere on the planet to determine their 3D position with great accuracy and precision.

–Department of Defense (DOD) – NAVSTAR –Russia GLONASS –European Economic Community System Under development Who maintains GPS?

The system is composed of three segments –Space - The orbiting satellites –Control - The monitoring stations on earth –User - The GPS units such as you will use today.

Garmin eTrex

When was GPS first used? –Sputnik…1957 –TRANSIT…1960’s –NAVSTAR…1970’s

– 27 at the current time – 24 to maintain a system How many satellites make up a GPS? Your GPS receiver must track at least 3 satellites to give you an accurate position location. *The word “tracking” must appear on the screen

–Government Military Agencies - Conservation, Weather, Rescue –Industry Transportation Fishing Agriculture –General Public Recreation Emergency / Security Reasons Health Related Reasons Who uses GPS?

–Each GPS satellite transmits an accurate position and time signal. –The user’s receiver measures the time delay for the signal to reach the receiver. –Measurements collected from 4 satellites are processed to solve for the 3D position, velocity and time. How does GPS Work?

Where on Earth are we?

Your Task Outside 1) Get a locked reading on your unit. 2) Chose a direction either east-west, or north-south. 3) Walk along the direction vector until the reading on your unit changes.

What you discovered outside. 1) Did you all get the exact same reading? 2) How did you know your direction? 3) How many paces until the reading on your unit changed?