The CORS network (www.ngs.noaa.gov/CORS/) is a multipurpose cooperative endeavor involving over 200 government, academic, and private organizations sharing data from their GPS tracking stations with NOAA.  NOAA analyzes and distributes the data free of charge in order to standardize positioning data across the country to the National Spatial Reference System maintained by NOAA.  The CORS network currently contains over 1,200 GPS tracking stations spanning the United States, its territories, and a few foreign countries.  Surveyors, GIS users and others can post-process their GPS data with GPS data from the CORS network to determine three-dimensional positional coordinates that approach a few centimeters in accuracy.  Alternatively, users can submit their GPS data to the web-based Online Positioning User Service (OPUS) utility (www.ngs.noaa.gov/OPUS/) to have NOAA compute such coordinates automatically.

WAAS (gps.faa.gov) monitors and corrects GPS signals for safe aircraft navigation across North America.  The first 25 WAAS stations have been contributing to CORS applications for nearly a decade. (Contact: This e-mail address is being protected from spam bots, you need JavaScript enabled to view it , tel: 301-713-3191 x103)