Protection of passive sensing use in the 18.6-18.8 GHz band

Passive spaceborne sensors provide important environmental data on a global basis. A set of frequency bands is essential for many of these measurements because simultaneous measurements at several frequencies are needed to isolate any single effect since the energy emitted at any one frequency is determined by several overlapping effects. The 18.6-18.8 GHz band is one required component in this set. Prior to the 2000 World Radiocommunication Conference (WRC-2000) of the International Telecommunications Union (ITU), the allocation for the Earth exploration-satellite (passive) service is on a primary basis in ITU Region 2 (essentially North and South America) but is on a secondary basis in Regions 1 (Europe and Africa) and 3 (Asia and Australia). These allocations must be elevated to primary status if the long-term ability to obtain environmental data with passive spaceborne sensors is to be preserved. Compatibility between the passive sensors and the active radio services requires adoption of constraints on the parameters of the fixed and fixed-satellite systems that use the band. These provisions will preserve the ability to use passive sensors to obtain vital environmental data for the benefit of all countries while preserving the ability of the fixed and fixed-satellite services to use the band