• Latest Accuracy Report— for the latest spreadsheet showing tested GPS accuracies, please click here.
  
  
• Tailoring GPS for the Forest Service: MTDC's Testing and Evaluation Program Username: t-d, Password: t-d
  
  
• Field Tests
  • Reports of GPS Receiver Accuracy tests made under tree canopy at 2 sites. Tests were made under eastern hardwood forests at the Ridley Creek, Pennsylvania test network and under western conifer forests at the Clackamas River, Oregon test network. The Trimble GeoXT, Trimble Pocket GPS, and the Garmin GPSMAP 76 GPS receivers were tested using National Standard for Spacial Data Accuracy testing procedures.
    • Trimble Geo XT at Ridley Creek, PA (Acrobat Document, 750 KB)
    • Trimble Geo XT at Clackamas River, OR (Acrobat Document, 113 KB)
    • Trimble Pocket GPS at Clackamas River, OR (Acrobat Document, 116 KB)
    • Garmin GPS MAP 76 at Clackamas River, OR (Acrobat Document, 44.8 KB)
    • Preliminary results for Garmin eTrex, Garmin GPS III with CSI Differential Correction (real time), Magellan Meridian Platinum at Clackamas River, OR (Acrobat Document, 54.1 KB)
      
      
  • "Comparison of GPS Receivers Under Forest Canopy with Selective Availability Off." This paper compares the accuracy performance of various mapping and recreational grade GPS receivers under forest canopy.
    • Comparison of GPS Receivers with SA Off (Word Document, 1.12 MB)
      
      
  • Pacific Northwest Region and MTDC Receiver Reports — Drafts of four reports on GPS receiver performance and accuracy under Western Oregon tree canopy by Santiago Mancebo and Ken Chamberlain are now available. These reports cover the Trimble ProXR and GeoExplorer 3, four models of recreational type GPS receivers manufactured by Garmin and Magellan, and the Rockwell PLGR P(y) code receiver. The receiver tests were made at the Clackamas Test Network in Western Oregon.
    • Garmin and Magellan Recreational GPS receivers (Word Document, 151 KB)
    • Trimble GeoExplorer 3 (Word Document, 83.5 KB)
    • Trimble Pathfinder Pro XR (Word Document, 70 KB)
    • Rockwell PLGR 96 (Word Document, 127 KB)
      
      
  • Trimble ProXL Real-time GPS Receiver Test Report
    
    
  • GPS Receiver Performance Under Tree Canopy Report
    
    
  • GPS Traverse Method Accuracy Report
    
    
  • Area Determination Using Walk Method Traverses
    
    
  • Comparing Four Methods of Correcting GPS Data
    
    
  • MTDC GPS Receiver Test Accuracies
    
    
  • Comparison of GPS Receivers at Puerto Rico Test Course

Other Forest Service GPS related information

• Forest Service GPS coordinators
• Contacts for USFS and Cooperators Trimble Community Base Stations