IEEE Geoscience and Remote Sensing Magazine - December 2021 - 280

Also note that some passive instruments (e.g., wideband
radiometers for cryosphere and salinity studies [5], [6]) are
planned to operate at 0.5-2.0 GHz without allocation.
AI 1.10: SHARING/COMPATIBILITY FOR
AERONAUTICAL MOBILE AT 15.4-15.7 AND
22.21-22.5 GHz
Resolution 430 (WRC-19) invites ITU-R to conduct
studies on spectrum needs for new nonsafety aeronautical
mobile applications for air-air, ground-air, and
air-ground communications of aircraft systems, particularly
for
◗ possible new primary allocations to the aeronautical
mobile service in the frequency band 15.4-15.7 GHz
◗ changing the primary 22-22.21 GHz allocation from
" mobile except aeronautical mobile " to " mobile " service,
which includes aeronautical mobile.
The bands 15.35-15.4 GHz and 22.21-22.5 GHz are
allocated to passive remote sensing systems as primary
and are adjacent to the frequency ranges considered in
this agenda item. However, currently no known missions
have used or are using the 15.4-15.7-GHz band.
The 22.21-22.5-GHz band is widely used for water vapor
measurements.
AI 1.12: POSSIBLE NEW SECONDARY ALLOCATION
TO EARTH EXPLORATION-SATELLITE SERVICE
(ACTIVE) AROUND 45 MHz
Resolution 656 (WRC-19) invites one to study a new secondary
allocation to the EESS (active) for spaceborne radar
sounders in the 40-50-MHz band. These sensors would be
used for investigating subsurface properties of polar ice and
arid regions.
The instruments would be spaceborne on a low Sunsynchronous
orbit at an altitude of around 400 km and be
subject to additional operational constraints, i.e., the radar
is to transmit only over some geographic areas (Antarctica,
Greenland, and the Sahara) at night between 3 a.m. and
6 a.m. local time to minimize errors due to ionospheric
perturbations and limit any impact on other radiocommunication
services.
Technical parameters are still being discussed for an
update of Report ITU-R RS.2455, " Preliminary Results
of Sharing Studies Between a 45-MHz Radar Sounder
and Incumbent Fixed, Mobile, Broadcasting, and Space
Research Services Operating in the 40-50-MHz Frequency
Range. "
AI 1.13: POSSIBLE UPGRADE OF 14.8-15.35 GHz
TO THE SPACE RESEARCH SERVICE
Resolution 661 (WRC-19) invites ITU-R to conduct sharing
and compatibility studies to determine the feasibility
of upgrading the space research service (SRS)
allocation to primary status in the frequency band
14.8-15.35 GHz, while still ensuring protection of the
primary services fixed and mobile within the band and
280
RAS, EESS (passive), and SRS (passive) in the adjacent
band 15.35-15.4 GHz.
Since the band would be used for transmitting and
receiving scientific data and related telemetry information,
this agenda item falls under the responsibility of
WP 7B. The 14.8-15.35-GHz band is already a primary
allocation for SRS in the U.S. Table of Allocations under
RR 5.340, and no emissions are allowed in the frequency
range of 15.35-15.4 GHz. The primary concern is the
potential for radio-frequency interference from out-ofband
emission (OOBE) caused by transmissions from
the adjacent band.
AI 1.14: ALLOCATIONS TO PASSIVE REMOTE
SENSING IN THE 231.5-252-GHz RANGE
This agenda item considers possible adjustments of the existing
or potential new primary frequency allocations to the
EESS (passive) in the frequency range 231.5-252 GHz, with
the purpose of better aligning the EESS (passive) allocations
created 20 years ago with updated passive sensor design
requirements or adding possible new allocations to the
EESS (passive).
Current EESS (passive) allocations are 235-238 GHz
and 250-252 GHz. The band 237.9-238 GHz is also allocated
to the EESS (active) for spaceborne cloud radars only.
These frequencies can be used for measurement of ice cloud
properties, and the 243.2-GHz band is being considered for
future ice cloud imaging passive sensors.
AI 1.15: GEOSTATIONARY EARTH STATIONS IN
MOTION AT 12.75-13.25 GHz
Agenda Item 1.15 is " to harmonize the use of the frequency
band 12.75-13.25 GHz (Earth-to-space) by Earth stations
on aircraft and vessels communicating with geostationary
space stations in the fixed-satellite service globally, in accordance
with Resolution 172 (WRC-19). "
The potential for OOBEs into the adjacent EESS (active)
allocation at 13.25-13.75 GHz is of particular concern
for the scientific services. Resolution 172 (WRC-19) also
mentions space-to-Earth operations at 10.7-10.95 GHz,
which is adjacent to the 10.6-10.7-GHz EESS (passive) frequency
band.
AI 1.16: EARTH STATIONS IN MOTION NEAR
18.6-18.8 GHz AND OTHER BANDS
Resolution 662 (WRC-19) invites the ITU-R to study and
develop technical, operational, and regulatory measures
for the use of the frequency bands 17.7-18.6, 18.8-19.3,
19.7-20.2 (space-to-Earth), and 27.5-29.1 and 29.5-30 GHz
(Earth-to-space) by Earth stations in motion (ESIM) in
nongeostationary orbit (non-GSO).
The ESIM operations are intended to provide broadband
data services to aeronautical (commercial and business aviation)
and maritime routes (passenger cruise and merchant
ships, fishing vessels, and so on) on a global basis. Within
the frequency bands under consideration, the bands
IEEE GEOSCIENCE AND REMOTE SENSING MAGAZINE DECEMBER 2021
IEEE Geoscience and Remote Sensing Magazine - December 2021

Table of Contents for the Digital Edition of IEEE Geoscience and Remote Sensing Magazine - December 2021
