Airbus Defence and Space

MetOp’s instruments

MetOp carries a comprehensive package of instruments for keeping all eyes on the weather

MetOp takes an awful lot of measurements. It takes profiles of atmospheric content, temperature and humidity, images land and ocean surfaces, peers into the clouds, tracks the changing contours and compositions of floating ice-masses, snow and vegetation cover, records wind speed and direction over the seas, identifies levels of gases such as carbon dioxide, nitrous oxide, methane and ozone, and of moisture in soil, and even keeps an eye on the impacts of solar activity – a vast amount of data which is channelled into weather-forecasting and climate monitoring models used by the meteorological community all over the world. In addition to sensors dedicated to the two mission main objectives of meteorology and climatology, MetOp carries instruments to provide a humanitarian service (search and rescue) and a space environment observation function.

Metop B Instruments

To do all this, the MetOp satellite carries a formidable array of 13 different instruments and sensors. Five are of state-of-the-art European design and manufacture, three of which are provided by Airbus Defence and Space. The other eight are identical to instruments also flown on the US’ National Oceanic and Atmospheric Administration (NOAA) satellites, under a pioneering transatlantic collaboration agreement between Eumetsat, the organisation responsible for MetOp operations, and NOAA. MetOp and its American partner satellite form the Initial Joint Polar-Orbiting Operational Satellite System (IJPS) constellation, flying in complementary orbits, hence offering maximum coverage, and sharing a common set of instruments for consistency of data, which are shared and exchanged. The NOAA satellite also carries one of the Airbus Defence and Space-built European instruments, the Microwave Humidity Sounder (MHS).

NOAA-18 was launched in 2005, with NOAA-19 following and taking over as primary in 2009 (these satellites have a shorter design life than the MetOp satellites).

Instrument

Type & mission

A-DCS (supplied by US)

Advanced Data Collection System

UHF receiver and signal processor, direct to ground transmitter

Environmental data collection and Doppler-derived location service

AMSU-A1 & AMSU-A2 (supplied by US)

Advanced Microwave Sounding Unit A

Microwave sounder with 15 channels in the 23–90 GHz range

Data used to provide precipitation and surface measurements, snow cover, sea ice concentration and soil moisture

ASCAT (supplied by Europe – Airbus Defence and Space)

Advanced SCATterometer

Pulsed radar in C-band

Measurements of wind velocity and direction over the oceans

AVHRR (supplied by US)

Advanced Very High Resolution Radiometer

Imaging radiometer with six channels in the 0.6–12.5 μm range

Images of land, water and clouds, measures sea surface temperature, ice, snow and vegetation cover

GOME-2 (supplied by Europe)

Global Ozone Monitoring Experiment

Nadir-viewing ultraviolet and visible spectrometer

Profiles of ozone, nitrogen dioxide and other minor trace gases

GRAS (supplied by Europe – Airbus Defence and Space)

GNSS Receiver for Atmospheric Sounding

Radio occultation receiver

Atmospheric profiles (temperature and humidity) through GPS radio occultation

HIRS (supplied by US)

High resolution Infra-red Radiation Sounder

Sounder with 19 infrared channels in the 3.8–15 μm range, and one visible channel

Atmosphere temperature profiles, moisture content, cloud height and surface albedo (spectral reflectance)

IASI (supplied by Europe)

Infrared Atmospheric Sounding Interferometer

Infrared Michelson Interferometer covering the 3.6–15.5 μm range

Atmosphere temperature and humidity profiles, sea and land surface temperatures, ozone totals

MHS (supplied by Europe – Airbus Defence and Space)

Microwave Humidity Sounder

Self-calibrating microwave sounder with five channels (89–190 Ghz)

Atmospheric humidity and surface radiation

S&R (supplied by US)

Search & Rescue Processor and Repeater (SARP-3, SARR)

VHF/UHF transponder and signal processor

Reception, processing and transmission of emergency signals of aircraft and ships in distress from beacons

SEM-2 (supplied by US)

Space Environment Monitor

Multi-channel charged particle spectrometer

Measurements of Earth radiation belt intensity, and flux of charged particles at satellite altitude

These instruments vary from the largely recurrent units (AVHRR, HIRS, AMSU-A1/A2) developed within the US Polar Orbiting Environmental Satellite (POES) programme to wholly new instruments developed specifically for MetOp (ASCAT, GRAS, IASI). With this package, the MetOp mission includes several enhancements over the NOAA meteorological polar satellites, such as the introduction of advanced sounding and surface wind measurement capabilities, advanced global ozone monitoring, direct data broadcast services, and the capability to obtain full resolution data from the complete orbit.

Don’t interfere!Extensive electro-magnetic testing was required to prove MetOp’s instruments could all work independently without causing interference with one another

One of Airbus Defence and Space’s responsibilities, over and above providing three of the major instruments, is the integration of the entire instrument suite in the satellite’s payload module. No sinecure, since the coexistence of powerful radio transmitters on one hand and extremely sensitive receivers in a large frequency band (100 MHz up to 200 GHz) on the other makes for very demanding payload accommodation considerations. In order to ensure that all instruments are able to operate without interfering with each other or the satellite, avoiding electromagnetic and radiofrequency (RF) interference between the instruments and avionics was one of the greatest design and verification challenges. A considerable amount of analysis, simulation and testing was required to prove this, all undertaken by Airbus Defence and Space as prime contractor.

MetOp-B instruments provided by Airbus Defence and Space

MHS (Microwave Humidity Sounder)

Earth ObservationMetOp