Glossary

A B C D E F G H I J K L M N O P Q R S T U V W

This glossary is a list of terms, acronyms and abbreviations that appear on Earth Online, the European Space Agency's Earth observation website.

AATSR

Advanced Along-Track Scanning Radiometer; this Envisat instrument was based on the same design as the ATSR-2 onboard ERS-2. It had four infrared channels and three visible channels. The swath, centered on the subsatellite ground track, was imaged under two different incidence angles in both spectral bands.

ACF

Auto-Correlation Function

A/D

Analogue / Digital

ADC

Analogue / Digital Converter

ADEN

ALOS Data European Node

ADEOS

Advanced Earth Observation Satellite - ADEOS website
The ADEOS satellites prime objectives were environmental research. ADEOS-1 was operational from 1996-1997. ADEOS-2 was operational from 2002-2003.

ADS

Annotation Data Set

ADSR

Annotation Data Set Record

Airbus Defence and Space

European Space company, prime contractor of the most ambitious spacecraft and instruments developed for ESA. See Airbus Defence and Space website.

ALOS

Advanced Land Observing Satellite - ALOS website
The ALOS mission was an Earth-imaging satellite. The data is used for cartography, and environmental and disaster monitoring. ALOS was operational from 2006-2011, ALOS-2 (SAR satellite) launched 2014 and is operational, and ALOS-3 (optical satellite) is under development.

AMF

Air Mass Factor; a parameter which allows the transformation from slant column densities to column densities along the line of sight.

AMI

Active Microwave Instrument, a part of ERS-1 and ERS-2 payload, incorporating image (SAR), wind (scatterometer), and wave (imagette) modes.

ANC

Ascending Node Crossing, the point in the orbit path of a satellite, where the orbit crosses the equator and the spacecraft moves from South to North.

Announcement of Opportunity; the call for proposals to utilize a satellite mission. Utilization can mean data exploitation but also the opportunity to provide payloads.

AOCS

Attitude and Orbit Control; an important and complex subsystem of the satellite, providing measurement of the attitude in nominal and anomalous situations, and a range of actuators to modify attitude and attitude rates. It also provides the thrusters needed for orbit control and maintenance.

AOI

Announcement of Opportunity Instrument. These instruments are developed independently of ESA, under national funding. They have been selected following an Announcement of Opportunity, one of the selection criteria being the extent to which the AOI would enhance the overall measurement system.

ASAR

Advanced Synthetic Aperture Radar

ASI

Agenzia Spaziale Italiana - ASI website
ASI is the Italian Space Agency

ASPS

Advanced Scatterometer Processing System

Astrium

European space company, now Airbus Defence and Space. ESA partners for the Envisat satellite.

ATBD

Algorithm Theoretical Basis Document

ATSR

Along Track Scanning Radiometer

AUIG

AlOS User Interface Gateway

Aura OMI

Aura Ozone Monitoring Instrument (OMI) - Aura is a NASA Earth Science mission that aims to study chemistry in the Earth's atmosphere. The OMI instrument is carried aboard the satellite and is a nadir-viewing UV/VIS imaging spectrograph that measures solar radiation backscattered by the Earth's atmosphere.

AVHRR

Advanced Very High Resolution Radiometer

BIH: Bureau International de l'Heure
BNSC: British National Space Centre - British governmental organisation that coordinated space activities in the United Kingdom. It was replaced on 01 April 2010 by the UK Space Agency.
BRDF: Solid State Recorder
BRM: Background Regional Mission
BUFR: Binary Universal Form (data format)


CAST: Chinese Academy of Space Technology - CAST website
CAST is a Chinese space agency that coordinates the national Chinese Space Programme.
CBERS: China Brazil Earth Resources Satellite - CBERS website
This satellite series is a cooperative program between CAST and INPE, to primarily provide China and Brazil with remote sensing imagery. The first three satellites (1, 2, and 2B) have been retired, CBERS 3 and 4 are operational.
CCD: Charge Coupled Device, an integrating optical detector in the near infrared, visible and ultraviolet region
CCT: Computer Compatible Tape
CEOS: Committee on Earth Observation Satellites - CEOS website
CEOS is an international body that coordinates civil space-borne Earth observation
CFRP: Carbon Fibre Reinforced Plastic, a very stiff, and lightweight material with negligible thermal expansion coefficient
CIS: Conventional Inertial System
CNES: Centre National d'Études Spatiales - CNES website
CNES is the French national space agency
COSMO-SkyMed: Constellation of Small Satellites for Mediterranean basin Observation
COSMO-SkyMed is a constellation of four satellites owned by ASI, aimed at providing Synthetic Aperture Radar imagery for both Civil and Military users.
CryoSat: Ice (Cryo) Satellite
CryoSat is designed to study ice in the polar regions, with a goal of understanding the role of ice in Earth's system. The first CryoSat satellite failed to reach orbit and was lost. CryoSat-2 has been operational since April 2010.
CSA: Canadian Space Agency - CSA website
CSA is the national space agency of Canada
CTS: Conventional Terrestrial System
CZCS: Coastal Zone Colour Scanner

DBU: Digital Bus Unit, which provides the electrical interface between the signals on the OBDH bus and terminal equipment such as ICU's.
DDS: Data Dissemination System
Deimos: The Deimos series are Earth Observation satellites owned by Deimos Imaging, and offer imagery for commercial applications as well as disaster monitoring. Deimos-1 is part of the Disaster Monitoring Constellation and has been operational since 2009, Deimos-2 launched 2014 and remains operational.
DEM: Digital Elevation Model
DESCW: Display Earth remote sensing Swath Coverage for Windows
DMC: Disaster Monitoring Constellation
The DMC is a series of two satellite constellations, as part of an international effort to monitor and provide observational support in the event of natural disasters. Three of the satellites in the First Generation constellation are currently operational, with the remaining two retired. The four satellites in the Second Generation constellation are all currently operational.
DMCII: Disaster Monitoring Constellation Imaging International - DMCii website
DMCii is a UK company which coordinates the Disaster Monitoring Constellation services.
DMI: DEIMOS Imaging - DEIMOS Imaging website
DEIMOS Imaging is a Spanish aerospace company which owns and operates DEIMOS-1, an Earth Observation satellite.
Dobson units: Dobson Units (DU) are used to measure atmospheric trace gases such as ozone. If you took all the molecules of ozone from a column of air, and compressed these molecules to the base of the column itself at STP (0oC and 1 atm), they would form a slab. One DU is defined to be 0.01 mm thickness of this slab. In the case of ozone, 1 DU corresponds to 2.69x1016 molecules per square centimetre of column base.
DORIS: Envisat Instrument for Doppler Orbitography and Radiopositioning Integrated by Satellite
DSB: {C}
DSR: Data Set Record
DUE: Data User Element
DVB: Digital Video Broadcasting

ECMWF: European Centre for Medium-Range Weather Forecasts - ECMWF website
The ECMWF is a European inter-governmental organisation that produces weather forecasts from Earth observation and remote sensing data.
EDI: ESA Developed Instrument. Such instruments are part of the Envisat industrial contract and are developed under full ESA responsibility
EM: Engineering Model
EMC: Electro-Magnetic compatibility
Envisat: ENVIronment SATellite
Envisat is an ESA environmental satellite that observes the atmosphere, ocean, land, and ice, with the goal of aiding environmental studies and climate change. Due to an anomaly on 8 April 2012 the mission was declared over on 9 May 2012.
EO: Earth Observation
EOHelp: ESA's Earth Observation Help and Order Desk
EOLi: Earth Observation Link (catalogue)
EOLi-SA: EOLi Stand Alone
EOMD: Earth Observation Market Development
EOPI: Earth Observation Principal Investigator (web portal)
ERS: European Remote Sensing Satellite
The two ERS satellites, owned by ESA, provided a broad range of environmental monitoring. ERS-1 was operational from July 1991 - March 2000. ERS-2 was operational from April 1995 - July 2011.
ESA: European Space Agency - ESA website
ESA is a multi-national European space agency that coordinates the space programme of Europe.
ESAC: Earth Science Advisory Committee
ESL: Expert Support Laboratory - The algorithms for Level 2 data processing comprise the retrieval of geophysical parameters from Level 1b (engineering) products. This step relies strongly on scientific inputs (e.g. methods for determining gas densities for atmospheric measurements) to be provided by scientific experts, i.e. the algorithms used in the operational processors are based on expert investigations. The Expert Support Laboratories are the formal implementation of this philosophy.
ESRIN: European Space Research Institute - ESRIN website
ESRIN is ESA's Earth Observation centre in Italy. It also serves as an interface between ESA and users of ESA's service, and is involved with international projects that make use of Earth observation.
EWFS: Envisat Web File Server

FD: Fast Delivery
FDGDR: Fast Delivery Geophysical Data Record, the standard RA GDR data product, available in slightly reduced quality within a few hours of measurement.
FFT: Fast Fourier Transform
FM: Frequency Modulated (eo) or Flight Model (Envisat)
FOCC: Flight Operations Control Centre, located at ESOC Darmstadt
FOS: Flight Operation Segment, composed of the Flight Operations Control Centre located at ESOC, Darmstadt and the associated command and control stations. It provides control of the satellite through all mission phases.
FORMOSAT-2: FORMOSAT-2 is an NSPO Earth Observation mission, with an objective to acquire high resolution imagery for a broad range of applications.
FR: Fast Registration
FR (image): Full Resolution
FTP (Server): File Transfer Protocol (server)

GCP Ground Control Points

GDP: GOME Data Processor
GDR: Geophysical Data Record; the basic Level 2 product of RA-2.
GEM: Goddard Earth Model
GISTDA: Geo-Informatics and Space Technology Development Agency - GISTDA website
GISTDA is public organisation in Thailand that develops and applies Earth observation satellite technology and Geo-Informatics for the benefit of Thailand as a whole.
GLI: Global Imager
GMES: Global Monitoring for Environment and Security - (now Copernicus)
GMES was a European Union-led initiative to perform and provide Earth monitoring in six themes: marine, land, atmosphere, emergency, security, and climate change.
GOCE: Gravity Field and Steady-State Ocean Circulation Explorer
GOCE is an ESA mission dedicated to studying Earth's gravity field and modelling the planet's geoid.
GOME: Global Ozone Monitoring Experiment
GOME is a nadir-scanning ultraviolet and visible spectrometer for global monitoring of atmospheric Ozone. The instrument operated aboard the ERS-2 satellite.
GOMOS: Global Ozone Measurement by the Occultation of Stars
GOMOS is a medium resolution spectrometer that operated aboard the Envisat satellite.
GOSAT: Greenhouse Gas Observing Satellite
GOSAT is a JAXA mission that aims to study global greenhouse gases and measure them, as well as monitor the atmosphere for Carbon Dioxide sources and sinks.
G-POD: GRID - Processing On Demand
GPS: Global Positioning System
GRACE: Gravity Recovery and Climate Experiment
GRACE is a joint mission between NASA and DLR, to measure Earth's gravity. Its secondary objective is to study the temperature and humidity in the atmosphere. The mission is composed of twin satellites working in conjunction.
GRS1984: Geodetic Reference System 1984
GSE: Ground Support Equipment
GSE (GMES): GMES Service Element


HDF: Hierarchical Data Format
HDDT: High Density Digital Tape
HH: Horizontal-Horizontal (polarisation)
HR (file): High Rate
HR (image): High Resolution
HLOP: High Level Operation Plan
HSM: High Speed Multiplexer, which assembles the payload science data into a continuous data stream
HV: Horizontal-Vertical (polarisation)

I: In-phase
ICU: Instrument Control Unit, a part of the distributed command and control function implemented on ESA spacecraft. The unit receives, decodes and executes high-level commands for its instrument, and autonomously performs health-checking and parameter monitoring. In the event of anomalies it takes autonomous recovery actions.
IFOV: Instantaneous Field of View
IGBP: International Geosphere-Biosphere Programme
IGDR: Interim Geophysical Data Record; the basic Level 2 product of RA-2. The term Interim refers to the fact that it is generated very soon after data acquisition so interim values of some parameters, such as the orbit, must be used until the full-precision values become available. Otherwise the product is identical to the GDR.
IJRS: International Journal of Remote Sensing
IKONOS-2: IKONOS-2 was a DigitalGlobe imaging satellite that aimed to deliver high-resolution Earth Observation imagery for commercial applications. It was operational 1999-2015.
INPE: Instituto de Pesquisas Espaciais - INPE website
INPE is a Brazilian research organisation dedicated to researching and applying space technologies.
IPF: Instrument Processing Facility
IR: Infrared
IRS: Indian Remote Sensing Satellite
IRS is an ISRO remote sensing series of satellites. IRS-P3 was an experimental craft, with the objective of performing Earth Observation and algorithm development. IRS-P3 was operational from 1996-2004. IRS-P6, also known as ResourceSat-1, has the goal of providing continued remote sensing data for land and water resources management, and has been operational since 2003.
ISCCP: International Satellite Cloud Climatology Project - ISCCP website
The ISCCP's goal is to collect weather satellite radiance measurements and to analyse them to infer the global distribution of clouds and their properties. This data is then used to study the role of clouds in the climate.
ISLR: Integrated Side Lobe Ratio
ISRO: Indian Space Research Organisation - ISRO website
ISRO's objective is to develop space technology and apply these technologies. ISRO has launched and operates a number of satellites to further this goal.

JAXA: Japan Aerospace Exploration Agency - JAXA website
JAXA is the national agency responsible for space development and research in Japan.
JERS-1: Japanese Earth Resources Satellite
JERS-1 was a joint JAXA/NASDA radar/optical mission with overall objectives of generating global datasets for resources surveying, establishing an integrated Earth observation system, and verifying instrument/system performance. The satellite was operational from 1992-1998.


KARI: Korea Aerospace Research Institute - KARI website
KARI is a Korean institute dedicated to aerospace research and developing and implementing applications in this field.
KOMPSAT: Korea Multi-Purpose Satellite
The KOMPSAT series, known as the Arirang series in South Korea, is a KARI mission providing Earth observation imagery for varied purposes, including disaster and environmental monitoring. KOMPSAT-1 was operational from 1999-2007. KOMPSAT-2 has been operational since 2006, KOMPSAT-3 launched 2012, KOMPSAT-5 launched in 2013 and KOMPSAT-6 is planned for the future.

Landsat MSS/RVB/TM/ETM/OLI/TIRS: Landsat is a joint NASA/USGS series of Earth Observing satellites. The MSS (Multispectral Scanner) was an instrument carried aboard Landsat 1 to Landsat 5 and performed high-resolution daytime acquisitions on a global basis and is still operational aboard Landsat 5. RBV (Return Beam Vidicon Camera) was an instrument carried aboard Landsat 1 to Landsat 3 and was used for cartography during daylight. TM (Thematic Mapper) is a multispectral scanning radiometer carried aboard Landsat 4 and Landsat 5, and is still operational aboard Landsat 5. ETM+ (Enhanced Thematic Mapper Plus) is an instrument carried aboard Landsat 7 and covers the visible, near-infrared, shortwave, and thermal infrared spectral bands. Landsat 8 carries the OLI (Operational Land Imager) and TIRS (Thermal Infrared Sensor) instrument.
LBR: Low Bit Rate
LEOP: Launch and Early Orbit Phase, the critical first few orbits where appendage deployments are performed and the satellite is brought into a stable configuration.
LIDAR: Light Detection And Ranging
LR: Low Rate
LRAC: Low Rate Reference Archive Centre, colocated with the Payload Data Handling Station in Kiruna. Its primary goal is to maintain a Level 0 reference archive for all Low Rate instruments for the lifetime of the mission.
LRR: Laser Retro-Reflector
LTO: Linear Tape-Open


MDA: MacDonald, Dettwiler and Associates - MDA website
MDA is a Canadian business that provides advanced information solutions to capture and process data, to produce information, and to improve decision making and operational performance of businesses and government organisations.
MDS: Measurement Data Set, a defined data entity within a product.
MERCI: MERIS Catalogue and Inventory
MERIS: Medium Resolution Imaging Spectrometer
MGVI: Meris Global Vegetation Index
MIPAS: Michelson Interferometer for Passive Atmospheric Sounding
MLST: Mean Local Solar Time, which in the context used here refers to the descending node of the sun-synchronous orbit. The true local solar time of the descending node varies by up to 15 minutes around this value due to the eccentricity of the Earth's orbit around the sun, which induces an uneven angular velocity around the sun, while the orbital precession rate is constant. This effect is known as the equation of time.
MPH: Main Product Header, the main description record at the start of every product, it follows a generic format.
MPP: Milestone Payment Plan
MS: Multi-Spectral
MWIR: Medium Wavelength Infrared
MWR: MicroWave Radiometer
The MWR instrument was aboard both Envisat and ERS missions: MWR (Envisat) MWR (ERS)
MWS: MicroWave Radiometer (sometimes referred to as MicroWave Sounder)


NASA: National Aeronautics and Space Administration NASA website
NASA is the national space agency of the United States of America
NASDA: National Space Development Agency
NASDA was the national space agency of Japan until it was merged with two other organisations and became JAXA in 2003
Nimbus-7: Nimbus-7 was a NASA mission to map chlorophyll concentration in water, sediment distribution, gelbstoff concentrations, and the temperature of coastal waters and ocean currents. It was operational from 1978-1986.
NIR: Near Infrared
NMSF: Net Multiplicative Scaling Factor
NOAA: National Oceanographic and Atmospheric Administration - NOAA website
NOAA is an American organisation dedicated to studying the the oceans and atmosphere in the interest of predicting changes to the climate, weather and oceans.
NOAA POES: NOAA Polar Orbiting Environmental Satellites - NASA POES website
The POES Project is a joint mission between NOAA and EUMETSAT, and consists of a constellation of weather satellites provided by ESA and NASA.
NRT: Near Real Time
N/S: North / South
NSPO: National Space Program Office - NSPO website
NSPO is the civilian national space agency of the Republic of China (Taiwan)

OBDH

On-Board Data Handling, this term is used in the context OBDH Bus, which is a synchronous serial data exchange and time-management network used on-board ESA spacecraft.

OBRC

On Board Range Compression

OCI

Ocean Colour Imager

OCM

Ocean Colour Monitor

OCTS

Ocean Colour and Temperature Scanner

Odin

Odin is an international astronomy and aeronomy mission with the objectives of performing atmospheric research, stratospheric ozone chemistry observations, mesospheric ozone science, summer mesospheric science, and the coupling of atmospheric regions.

OGRC

On Ground Range Compression

OSMI

Ocean Scanning Multispectral Imager

PAC: Processing and Archiving Centre; a concept which evolved from the PAF's of the ERS era. Their development and implementation is funded on a national basis while the operation for the services defined in the Payload Data Segment concept is provided by ESA.
PAF: Processing and Archiving Facility of the ERS-1/2 mission. Four PAFs are operational. These are the D-PAF (located at the German Remote Sensing Data Centre (DFD) at the DLR premises at Oberpfaffenhofen/Germany), the F-PAF at IFREMER (Brest/France), the I-PAF in Matera/Italy and the UK-PAF in Farnborough/UK.
PAN: Panchromatic
PAR: Photosynthetically Active Radiation
PCD: Product Confidence Data, a coded set of quality flags generated at various stages of data processing.
PDHS: Payload Data Segment, comprises all those elements which are related to payload data acquisition, processing, archiving and those concerning the user interfaces and services.
PDS: Payload Data Segment, comprises all those elements which are related to payload data acquisition, processing, archiving and those concerning the user interfaces and services.
PEB: Payload Equipment Bay, part of the Payload Module of the Polar Platform.
PI: Principal Investigator
PLC: Payload Carrier, part of the Payload Module of the Polar Platform.
Pleiades: Pleiades is a CNES constellation of two satellites which aim to provide high resolution optical imaging using advanced Earth Observation technologies.
PLM: Payload Module, the part of the Polar Platform which is mission-specific.
PMC: Payload Management Computer, located in the Payload Module, is responsible for command and control of the payload. It communicates with the on-board computer in the Service Module.
POLDER: Polarization and Directionality of the Earth's Reflectances
PPF: Polar Platform, a multimission spacecraft designed to accommodate large payloads in a sun-synchronous low earth orbit.
PPTL: Processor Point Target Linearity
PRARE: Precise Range and Range-rate Equipment
PRF: Pulse Repetition Frequency, the rate at which (typically) a radar emits transmit pulses.
PRI (data format): Precision Image (data format)
PRI: Pulse Repetition Interval, the interval between radar pulses.
PROBA: Project for On-Board Autonomy
PROBA is an ESA mission, that was originally intended as a technology demonstration mission. Since then the original PROBA-1 satellite, and PROBA-2 and PROBA-V have also provided Earth Observation data and monitoring. PROBA-3 is in development.

Q: Quadrature
QA: Quality Assurance
Q/L: Quick-look
QuickBird-2: QuickBird-2 is a DigitalGlobe imaging satellite providing commercial high resolution Earth Observation imagery.
QuikSCAT: Quick Scatterometer; a NASA mission that aimed to take ocean-wind measurements to aid in weather forecasts and climate research. The satellite was launched in 1999 and ceased functioning in 2009.

RA: Radar Altimeter
RA-2: Radar Altimeter-2
RA (archive): Rolling Archive
RAC: Reflective Acoustic Coupling; a type of surface acoustic wave device in which the acoustic signal undergoes a reflection.
RADARSAT: RADAR Satellite
RADARSAT is a joint CSA/MDA mission consisting of two Earth observation satellites. RADARSAT-1 was operational 1995-2013, and RADARSAT-2 was launched in 2007 and remains operational.
RapidEye: RapidEye is an Earth Observation mission of RapidEye AG and is a constellation of five satellites, providing imagery on a commercial basis.
RMS: Root Mean Square
RR: Reduced Resolution
RS: Remote Sensing
RTU: Remote Terminal Unit, a semi-intelligent device which is linked to the PMC by the OBDH bus and which provides control and monitoring functions for relatively simple equipment such as power distribution units.


SAG: Science Advisory Group
SAGE: Stratospheric Aerosol and Gas Experiment - SAGE III website
SAGE is a series of NASA remote sensing instruments, part of the NASA Earth Observing System. The three SAGE instruments have been used aboard satellites to study the atmosphere. The satellites that carried the first three instruments are no longer operational, but a fourth, SAGE-III-ISS, was installed aboard the International Space Station in 2017.
SAOCOM: Satellites for Observation and Communications; is an Earth observation satellite constellation launched by Argentina's space agency CONAE.
SAR: Synthetic Aperture Radar
SAW: Surface Acoustic Wave, refers to a device in which acoustic waves propagating on the surface of a piezo-electric crystal transfer a signal between two transducers. Extensively used for delay lines, both dispersive and non-dispersive.
SBUV: Solar Backscatter Ultraviolet, flown on NOAA weather satellites
S/C: Spacecraft
SCATT: Scatterometer
SCIAMACHY: Scanning Imaging Absorption Spectrometer for Atmospheric Cartography
SciSat: SciSat-1/ACE is a CSA atmospheric science mission.
SeaWiFS: Sea-Viewing Wide -Field-of-View Sensor - SeaWiFS website
SeaWiFS was a GeoEye instrument that operated aboard the OrbView-2 satellite. The instrument's objective was to measure reflected visible sunlight from the ocean's surface. The instrument operated from the launch of OrbView-2 in 1997 to 2010, when communications were lost with the satellite.
SHARP: Standard-family HRPT Archive Request
SLC: Single-Look Complex (dataset)
SLR: Satellite Laser Ranging station.
SMOS: Soil Moisture and Ocean Salinity
SMOS is an ESA mission that aims to gather global observations of soil moisture and ocean salinity, leading to an improved understanding of Earth's water cycle and helping to predict weather and climate forecasting.
SNSA/SNSB: Swedish National Space Agency - SNSA website
The SNSA, previously know as Swedish National Space Board (SNSB), is a Swedish government agency responsible for national and international space and remote sensing activities, primarily in the fields of research and development.
SPH: Secondary Product Header.
SPOT: Satellite Pour l'Observation de la Terre
The SPOT mission is a series of Earth Observation satellites that have provided high-resolution optical imagery since 1986. Spot Image and CNES are responsible for the first five satellites, and Spot image and Astrium are planning two further satellites in the series for the future. SPOT 1 was operational from 1986-2003. SPOT 2 was operational from 1990-2009. SPOT 3 was operational from 1993-1996. SPOT 4 was operational from 1998-2013. SPOT 5 was operational from 2002-2015. SPOT 6 and SPOT 7 are currently operational.
SRTM: Shuttle Radar Topography Mission - SRTM website
SRTM was an international mission between NASA/NGA, DLR, and ASI. It was an instrument that was carried aboard the shuttle Endeavour in 2000 and obtained elevation data on a near-global scale with the goal of creating a high-resolution digital topographic database of Earth.
SSH: Sea Surface Height
SSR: Satellite System Receiver
SST: Sea Surface Temperature
SSTL: Surrey Satellite Technology Limited - SSTL website
SSTL is a British company that provides international services for designing, manufacturing, launching and operating small satellites and associated technologies. They also provide consultancy and research and development services.
StM: Structural Model
STP: Standard Temperature (0oC) and Pressure (1 atm)
SWIR: Short Wave Infrared


TDT: Terrestrial Dynamic Time
TEKES: TEKES/Business Finland website
TEKES, now referred to as Business Finland, is the national funding agency for technology, innovation trade and travel in Finland.
THEOS: Thailand Earth Observation System - THEOS mission description
THEOS is an Earth Observation mission of GISTDA, to provide affordable access to space for Thailand and operational experience for future space missions.
TIR: Thermal Infrared
TM: Telemetry
TOA: Top of Atmosphere
TOMS: Total Ozone Mapping Spectrometer, flown on Nimbus-7 and operational in 1978-1988.
TopSat: TopSat was a low-cost UK collaborative mission that served as a demonstration satellite in exploring the capabilities of high-resolution imaging on small satellites.
TPM: Third Party Mission
TPMO: TPM Owner/Operator
TT&C: Tracking, Telemetry and Control, a term used to refer to the ground stations used in the day-to-day monitoring and control of a satellite. In the case of Envisat this function is performed by conventional S-band low-rate links to a ground station located in Kiruna.
TWT: Travelling Wave Tube, a microwave amplification device, which works by transferring energy from an electron beam to a wave propagating in a helix structure within the tube.


UET: User Earth Terminal
UNCFCCC: United Nation Framework Convention on Climate Change
UPS: Universal Polar Stereographic
USGS: United States Geological Survey - USGS website
USGS is a scientific organisation dedicated to studying the ecosystem and environment, natural hazards, and natural resources, and the impacts of climate and land-use change.
USO: Ultra Stable Oscillator. an oscillator with a long term frequency stability of the order 10^8.
UTC: Universal Time Coordinate (eo) or Universal Time Corrected (ENVISAT)
UTM: Universe Transverse Mercator
UV: Ultraviolet

VIS: Visible
VH: Vertical-Horizontal (polarisation)
VV: Vertical-Vertical (polarisation)

WRS: World Reference System
WS: Wind Scatterometer
WSC: Wind Scatterometer

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