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ISRO SAC Indian National Satellite (INSAT-3D) Radiometer

2003 - 2008

Project overview

The INSAT-3D instrument is an advanced infrared geostationary meteorological satellite being developed by the Indian Space Research Organisation (ISRO) Space Applications Centre (SAC) for high resolution monitoring of temperature and trace chemical species in the atmospheric regions between the troposphere and stratosphere. INSAT-3D is one of three satellites under development by ISRO exclusively to improve domestic weather forecasting and track cyclones and monsoons originating from the Bay of Bengal and Arabian Sea. The instrument comprises a six channel imaging radiometer designed to measure radiant and solar reflected energy from areas sampled on the Earth and a high resolution infrared sounder to measure vertical temperature profiles, humidity, surface and cloud top temperatures, and ozone distribution. It is planned for launch on theGSLVMk.2 launch vehicle in 2008 for deployment in a 38; 500km equatorial plane geostationary orbit. This orbit will provide a continuous stationary view over the Indian Ocean for regular observations of cloud patterns and monitoring of the path of tropical cyclone formations to predict the time and place of landfall for disaster warning. The INSAT-3D sounder instrument measures radiation using 19 precision narrow-bandpass interference filters to isolate and discriminate between spectral bands. The filters reported here are particularly notable for their demanding combination of large-shaped coating aperture, tolerance of coating uniformity, and positional accuracy of spectral placement.

The University of Reading has been responsible for the design and manufacture of the MWIR and LWIR narrow-bandpass filters defining the spectral band definition of the instrument. The payload instruments are required to operate for a lifetime of 7 years after launch.

Delivered hardware

Description Filter Type Quantity Wavelength Region Substrate Material Dimensions

MWIR Filters

Narrow bandpass filter 5 channels 6.5 - 11.3 µm

Germanium (Ge)

25.0 mm W x 40.0 mm L x 5.0 mm T (arc-shaped)
LWIR Filters Narrow bandpass filter 7 channels 12.0 - 14.7 µm

Germanium (Ge)

30.0 mm W x 80.0 mm L x 5.0 mm T (arc-shaped)





INSAT-3D Liftoff

Further information

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