Testing the GPS performance in a forested area

摘要

The Navstar Global Positioning System (Navstar GPS) was developed in the late sixties by US Department of Defense (DOD) for strategic navigation. The system provides accurate, continuous, worldwide, three-dimensional position and velocity information. Civilians make extensive use of its capabilities and outnumber those of the military. Because of its high accuracy and continuous availability, GPS makes an excellent choice for Geographic Information System (GIS) data capture. In 1992, the USDA Forest Service GPS Steering Committee has identified more than 130 GPS forest applications. Extensive tests have been conducted at the Austin Cary Memorial Forest of the University of Florida. They include mapping of forest boundaries, firelines, forest stands, access roads, permanent plot centers, wetlands, inventory of facilities as well as vegetation and wildlife monitoring. In addition, GPS is also used in daily operations ranging from forest fire mapping, fire management, timber loss, timber sales, wetland restoration, forest drainage management, and navigation to permanent plot centers using handheld GPS units. Data collected-with GPS is stored in GIS databases for decision making and management of the forest. A comparison between the traditional digitized map and GPS-derived GIS datasets reveals improved accuracy of the latter. Resulting implications related to various management models were also evaluated.