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Global Positioning Systems
Geo-caching in the National Parks
Geo-caching can include activities such as placing an item in a location for someone else to find or simply publishing coordinates of locations for others to find and describe the item at that location. Geo-caching activities on national park lands is prohibited, however some activities are permitted under special conditions as determined by the individual park. You are required to notify park headquarters if you are participating in this type of activity. NPS Policy Document->>

The History of GPS
"For centuries, navigators and explorers have searched the heavens for a system that would enable them to locate their position on the globe with the... MORE->>

What is GPS?
The Global Positioning System is a constellation of 25 or more Department of Defense satellites that orbit the earth approximately every 12 hours. The position and time information transmitted by these satellites is used by a GPS receiver to trilaterate a location on the earth... MORE->>

GPS System Status
Information concerning the system status of GPS can be found at the US Coast Guard Website... MORE->>

Differential Corrections and Basestations
GPS basestations are used for differential corrections of field collected GPS data. This mitigates the GPS signal degrading effects of the atmosphere and gives a more accurate position, typically less than 5 meters. Differential corrections are achieved by utilization of two GPS receivers... MORE->>

GPS Orbit Image