November 26, 2010 WMCI

WHAT IS GPS? The Global Positioning System (GPS) is a navigation and precise-positioning tool.GPS Developed by the Department of Defense in 1973, GPS was originally designed to assist soldiers and military vehicles, planes, and ships in accurately determining their locations world-wide.Department of Defense Today, the uses of GPS have extended to include both the commercial and scientific worlds. Commercially, GPS is used as a navigation and positioning tool in airplanes, boats, cars, and for almost all outdoor recreational activities such as hiking, fishing, and kayaking. In the scientific community, GPS plays an important role in the earth sciences. Meteorologists use it for weather forecasting and global climate studies; and geologists can use it as a highly accurate method of surveying and in earthquake studies to measure tectonic motions during and in between earthquakes.

HOW DOES GPS WORK?

Three distinct parts make up the Global Positioning System. We will look at the first only: The first segment of the system consists of 24 satellites, orbiting 20,000 km above the Earth in 12- hour circular orbits. This means that it takes each satellite 12 hours to make a complete circle around the Earth. In order to make sure that they can be detected from anywhere on the Earth's surface, the satellites are divided into six groups of four. Each group is assigned a different path to follow. This creates six orbital planes which completely surround the Earth.

These satellites send radio signals to Earth that contain information about the satellite. Using GPS ground-based receivers, these signals can be detected and used to determine the receivers' positions (latitude, longitude, height.)

WAAS? WAAS stands for Wide Area Augmentation System, a set of satellites that broadcast additional signals to supplement those from the basic GPS satellites. A GPS that can receive WAAS signals is accurate to better than 3 metres, 95% of the time (compared to a typical accuracy of 15 metres without WAAS.) WAAS works best with an unobstructed sky view (on open land or water.) WAAS signals are currently available only in the US and Canada.

TYPES OF GPS RECEIVERS VEHICLE Have a large screen built-in battery (short life) Easily installed/removed (unless built-in) Can use software to add POI Great for road trips HAND-HELD Small Usually use replaceable batteries Can use a “powercord” Can use software to add POI Good for lessons, outdoor activities…

HOW SHOULD I GET STARTED IN GPS? If you have never used a GPS receiver, keep in mind that they have never been easier to use and have never been more affordable. Are you allergic to technology? If so, the Wilderness Supply Company sells instructional dvd’s specific to a model of GPS and offer courses in using them!

WHAT ARE SOME BASIC GPS LESSONS? Latitude/longitude Finding a route Retracing a route Making waypoints POI (points of interest) Using trip data Geocaching

WHERE CAN I FIND GPS LESSONS? There are plenty of websites with lessons:

WHAT IS GEOCACHING? Geocaching is a worldwide game of hiding and seeking treasure. A geocacher can place a geocache in the world, pinpoint its location using GPS technology and then share the geocache’s existence and location online. Anyone with a GPS unit can then try to locate the geocache.

GEOCACHING AND YOU Two useful websites for getting started in geocaching are:

KIDS, GPS AND $$$ Receivers are expensive, so how do I get a class set? Answer: you probably can’t get enough for your class on your own, but students likely have access to family receivers and could bring theirs in for small group activities! Using geocaching as a hook, you might be introducing kids to a new sport too!

VIDEO TIME! (10 minutes) Creating waypoints Navigating to a waypoint Route navigation Working with maps

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