GIS Live 2005
"Open Spaces - Wild Places"

Sessions Previews

GPS and You
Curt Johnson, NC Geodetic Survey

Description:

Global Positioning Systems

Learn how GPS can make GIS real by allowing you to collect your own spatial data while investigating your community's social, economic, and ecological systems.

The Global Positioning System is a space based navigation system. A constellation of 24 satellites orbits earth every 12 hours at an altitude of 14,000 miles from the earth's centre. Each satellite is armed with four atomic clocks, which keep the time to a superlative degree of accuracy. They each broadcast their precisely timed radio signals through the atmosphere and onto the earth's surface at the speed of light. The signals from each satellite arrive at any particular point on or above the earth's surface at slightly different times. This timing is proportional to the distance between the satellite and that particular point. Thus each radio beam acts as a 20,200 km (10,900 nm) long ruler.

GPS is used to support land, sea, and airborne navigation, surveying, geophysical exploration, mapping and geodesy, conservation research, habitat modelling, vehicle location systems, farming, transportation systems, archaeology, mountaineering, fishing and a wide variety of other additional applications.

Preparing for the Session: Activities for Parents and Educators to engage in:

(K) What do you KNOW about this already?

What do you already know about GPS? Have you ever seen or used a GPS receiver before? Where did you see it? How have you used GPS?

(W) What have you LEARNED?

What have you learned about how GPS works and how it is used?

(L) What else would you LIKE TO KNOW?

If you had a GPS receiver how would you use it? What are some other applications of GPS?