On April 3, a small satellite carrying a shoebox-sized radio receiver was launched into low earth orbit to test a concept known as GPS/MET. GPS/MET would use radio signals from the U.S. Air Force's 24 Global Positioning System (GPS) satellites to gather meteorological data around the globe. The experimental receiver will catch the GPS radio beams 500 times a day as the satellites rise and set at the earth's horizon. If temperature and humidity data can be successfully derived from refraction of the radio beams as they pass through the atmosphere, what has been a source of noise for those relying on GPS signals as a navigational aid or for measuring tectonic movements could be a valuable signal for meteorologists and climatologists.
The project is funded by NSF, the Federal Aviation Administration, NOAA, and NASA. Scientific participants are UOP's University NAVSTAR Consortium (UNAVCO), NCAR, NASA's Jet Propulsion Laboratory (JPL); and the University of Arizona. UNAVCO director Randolph Ware is principal investigator. Orbital Sciences Corporation is responsible for the launch vehicle, satellite, and operations. Allen Osborne Associates helped develop the GPS receiver for the test.
The early-morning launch went exactly as planned and by evening of the same day it was confirmed that the satellite was successfully in its intended orbit. Benjamin Herman of the University of Arizona says, "If this experiment works, the wealth of high-resolution data that will be available for studying climate change and for weather forecasting will be tremendous. This would be a very economical way of obtaining global weather and climate data with a time and space resolution that is undreamed of with current systems."
According to GPS program manager Michael Exner, "A constellation of 50 to 100 GPS microsatellites, each small enough to be carried by one person, could provide real-time global data for about the cost of one conventional weather satellite, including launch costs." For further information, contact Exner (email@example.com; 303-497-2601).