WRC-2000 agreed to new allocations and sharing criteria for science services (particularly to allow passive services to coexist with other active services). However, WRC-03 will be looking at further possibilities for allocating spectrum to space science services in various parts of the spectrum and in this respect SG 7 is involved in studies on the provision of new spectrum and associated sharing conditions; [(e.g. 3 MHz of spectrum req’d for telecommand uplinks between 100 MHz and 1 GHz; sharing studies between SRS (deep space) and ISI at 32 GHz; new allocations to EESS and SRS around 5 GHz); (Res 723 and Res 736).]
Another example is the need for sharing studies between precipitation radars and other services at around 35 GHz (e.g. radioloc.); (Res 730). Note – precipitation radars are used for the measurement of rain rate and global water circulation.
Need to explore possibility of using band 420-470 MHz for EESS (active) – forest cover and rate of degradation; (Res 727). Note – frequencies around 450 MHz very suitable for observing the rate of forest degradation; (synthetic aperture radars).
Continuing need to study sharing possibilities and necessary criteria to allow RA to coexist with other active services (many of which are new). Picture 1 shows the levels at which interfering signals become harmful to RA (in bands dedicated to RA observations). Picture 2 indicates eirp vales for a TX to share at a given frequency for a LOS interference path. The use of digital modulation can result in extended sidebands which, in turn, could result in spurious or OOB emissions falling in an RA band; e.g. DAB transmissions close to RA band at 1 400 MHz.
