The GPS antennas are mounted on the roof near the instrument. This allows optimum reception of the GPS signal for accurate timing and location.
U.S. Department of the Interior | U.S. Geological Survey URL: https://pubsdata.usgs.gov/pubs/of/2001/ofr-01-0344/GPSantenna.html Questions or Assistance: USGS Web Contact Page Last Modified: Fri Jan 11 02:15 EDT 2013
