For the reader’s convenience, following is an alphabetical list of selected acronyms and abbreviations used in this handbook. Designations for footnotes to science service allocations are then listed.

Ae aeronautical

AeMS Aeronautical Mobile Service (MS with aircraft)

AeMSS Aeronautical Mobile Satellite Service (MSS with aircraft)

AeRLS Aeronautical Radiolocation Service

AeRNS Aeronautical Radionavigation Service

AMatSat Amateur Satellite Service

AmS Amateur Service

AMSU Advanced Microwave Sounding Unit

ANS Air Navigation Service

Bn necessary bandwidth

BS Broadcasting Service

BSS Broadcasting Satellite Service

CCIR International Radio Consultative Committee (antecedent of the ITU-R)

E→S Earth to space

EESS Earth Exploration-Satellite Service

EOS Earth Observing System

FS Fixed Service (point-to-point transmissions, such as radio relay towers)

FSS Fixed Satellite Service (between satellites and fixed ground stations, such as telephone, television, data links)

GEO geostationary orbit (satellite)

GNSS Global Navigation Satellite System

GOES Geostationary Operational Environmental Satellites

GPS Global Positioning System

IAU International Astronomical Union

IGS International Global Navigation Satellite System (GNSS)

ISM industrial, scientific, and medical (bands in which radio-frequency-noisy systems can be operated); interstellar medium (consisting of the gas, dust, atomic particles, and magnetic fields between the stars)

ISS Inter-Satellite Service

ITU International Telecommunication Union

ITU-R Radiocommunication Sector of the ITU

ITU-RR ITU Radio Regulations

IUCAF Scientific Committee on Frequency Allocations for Radio Astronomy and Space Science

LEO low Earth orbit

LMS Land Mobile Service

LMSS Land Mobile Satellite Service

MetAids Meteorological Aids Service (radiosondes, etc.)

MetSat Meteorological Satellite Service

MMSS Maritime Mobile Satellite Service

MS Mobile Service

MSS Mobile Satellite Service (telecommunications between mobile stations and satellites)

NASA National Aeronautics and Space Administration

NOAA National Oceanic and Atmospheric Administration

NTIA National Telecommunications and Information Administration

OOBE out-of-band emission

pfd power flux density (usually measured in Wm⁻²)

RAS Radio Astronomy Service

RDSS Radiodetermination Satellite Service

RFI radio-frequency interference

RLS Radiolocation Service (radars)

RNS Radionavigation Service

RNSS Radionavigation Satellite Service (for example, GPS)

RR Radio Regulations (the international treaty governing spectrum use)

S→E space to Earth

S→S space to space

SAR synthetic aperture radar

SETI search for extraterrestrial intelligence

SFS Standard Frequency and Time Signal Service (such as WWV)

SFTSS Standard Frequency and Time Signal-Satellite Service

SOS Space Operations Service

SpaceOps Space Operations Service (satellite command and control)

spfd spectral power flux density (measured in Wm⁻² Hz⁻¹)

SRS Space Research Service

SSM/I Special Sensor Microwave/Imager (of the Defense Meteorological Satellite Program)

SSM/T Special Sensor Microwave/Temperature (of the Defense Meteorological Satellite Program)

TDRSS Tracking and Data Relay Satellite System

TRMM Tropical Rainfall Measurement Mission

VLA Very Large Array

VLBA Very Long Baseline Array

VLBI very long baseline interferometry

WARC World Administrative Radio Conference (antecedent of WRC)

WRC World Radiocommunication Conference

• 5: Footnotes designated “5” (e.g., 5.364) come from the ITU Radio Regulations (see Appendix B.1).

• US: Footnotes consisting of the letters “US” followed by one or more digits (e.g., US13) denote stipulations applicable to both government and nongovernment services (see Appendix B.2).

• G: Footnotes consisting of the letter “G” followed by one or more digits (e.g., G59) denote stipulations applicable only to U.S. federal government services (see Appendix B.3).

• NG: Footnotes consisting of the letters “NG” followed by one or more digits (e.g., NG101) denote stipulations applicable only to U.S. nonfederal government services (see Appendix B.4).