Through NSF funding in the early 1990's, a number of LTER sites acquired GPS units to located and survey LTER research sites.  Included in the work was an acquisition of high resolution survey-grade GPS units which were placed into the UNAVCO instrument pool.  These instruments can be acquired by LTER research for use by contacting Jeff Jefferson at the University of North Carolina and coordination with UNAVCO contact Barbara Perin 

The  removal of  "selective availability" on May1, 2000, and recent development and integration of  the Wide Area Augmentation System (WAAS) can provide position accuracy better than 3 meters on GPS receivers as inexpensive as $150 from companies including Garmin, Trimble, Magellen and others.