Under the agreement, the UCAR Foundation has licensed UCAR's GPS/MET intellectual property, primarily software, to PDI. In exchange, the foundation received an equity ownership position. PDI now has exclusive commercial rights to the GPS/MET technology and the resulting data. UCAR-affiliated scientists will retain access for research purposes.
The founders of PDI are GPS/MET program director Mike Exner (president and chief executive officer) and University Navstar Consortium director Stick Ware (chair of the board of directors). Mike will continue as a half-time UCAR employee through this fall; Stick will remain at UCAR full time.
"We're moving into a new era," says Mike. "We need more private and public sector cooperation to advance the public's interest in better weather and climate prediction."
The first GPS/MET instrument was launched in April 1995 to intercept signals from GPS satellites as they are occulted by the earth's atmosphere. By measuring the increments of signal delay induced by density and moisture gradients in the atmosphere, scientists can deduce temperature, moisture, and pressure at heights from 0 to 60 kilometers (0-35 miles). The signals also yield electron density profiles in the ionosphere. Validation experiments conducted at UCAR and elsewhere show that the vertical temperature profiles are typically accurate to less than 1 degree Celsius between about 5 and 40 km (3-25 miles). The average vertical resolution ranges from 200 meters (660 feet) in the troposphere to 1.5 km (1 mile) at the stratopause.
Despite the encouraging test results, the research community has been slow to finance expansion of GPS/MET, whose initial grant ends in fiscal 1997. "Federal funding for new observing systems is in short supply," notes Mike. At the same time, he adds, "many policy makers are strongly encouraging private investment in space-based businesses."
According to Mike, PDI can bring the cost of GPS/MET data down by using market mechanisms to expand the potential user base. "Right now, no would-be user has the money to finance a system outright." He estimates that a constellation of around eight GPS/MET instruments could provide global coverage every two hours with some 4,000 soundings a day. Such data could be applied to operational weather forecasting, climate monitoring and analysis, and space weather prediction. The data's usefulness would be bolstered by full global coverage, unhindered by rain or clouds. Moreover, says Mike, biases produced in other satellite-based systems by long-term instrument drift and satellite transitions would be virtually nil with a GPS/MET constellation.
PDI is currently seeking private capital and has offered to sell data to NASA, which has expressed interest in data products derived from GPS occultation. Should the company receive a major contract, Mike foresees that much of the research and technical work would be subcontracted to UCAR. "We're going to build up the physical capabilities of the GPS/MET system within PDI, but most of the science will continue to take place at UCAR." BH
PDI can be found on the World Wide Web.