InterMet has developed a new, digital, high-accuracy upper-air 403 MHz radiosonde system with a portable ground station that is applicable to synoptic as well as military applications. The ground station is small and light weight and is easily moved to a new site. It can be set up by one person in less than 10 minutes. For non-military applications, a C/A code GPS receiver is provided, while, for military applications, a P(Y)-code SAASM compliant GPS receiver is used. The radiosonde has the same high accuracy pressure, temperature and humidity sensors used on the InterMet radiosonde developed for the U.S. National Weather Service.

Setup of the radiosonde before launch is exceptionally easy. Radiosonde unique calibration coefficients are stored in the radiosonde, power is provided by dry cell batteries, and calibration before launch is not required. This paper present details of the design and performance of the system.