Abstract
The Precipitation Radar (PR) onboard the Tropical Rainfall Measuring Mission (TRMM) satellite, the first rain radar in space, has been developed jointly by National Space Development Agency of Japan (NASDA) and Communication Research Laboratory (CRL), based on a basic research conducted at CRL since 1980s. From a series of tests on the ground before launch, the PR was found to meet almost all the specifications. It has also been confirmed from the initial check-out conducted just after the TRMM launch that the PR functions normally and holds the same performance as those measured before launch.
