Observing the Earth – Journey of Indian Earth observation satellites from Bhaskara to EOS

 

From the humble start from Bhaskara I to EOS-1, the Indian Earth observation satellite technology has advanced significantly. Earlier, the technology required by the Indian satellite system was imported from foreign nations, however with time state of the art technology has been developed indigenously. In this short journey, there has been remarkable advancement of technology in the earth observation satellite in resolution, sensor technology, application areas, coverage etc.

Experimental stage - The beginning of the Indian earth observation satellite journey started with experimental satellites like Bhaskara I in 1979 followed by Rohini RS-D1, Bhaskara II and Rohini RS -D2. These had limited capabilities in terms of sensor and resolution.

IRS series - In 1988, Indian Space Research Organization launched the first indigenous operational remote sensing satellite in the IRS series, i.e  IRS – 1A. After this came the many satellites in IRS series i.e. 1A, 1B, 1E, P2,1C, P3, 1D, P4 and P6, each with improved capabilities than the previous one. IRS- P6 (which was continued as Resourcesat), launched in 2003, employed advanced multi-spectral LISS IV, LISS III and AWiFS sensor. The latest in this series is Resourcesat 2-A, launched in 2016, with much improved technology.

Oceansat series – The IRS – P4 satellite, launched in 1991, specifically for ocean applications was first one in the Oceansat series. The second satellite in this series is Oceansat -2 launched in 2009 with Ocean Colour Monitor-2 (OCM-2), Scatterometer and Radio Occultation Sounder for Atmospheric (ROSA) sensors.  SCASAT – 1 is the continuing mission for Oceansat series with wind scatterometer sensor. The third one in this series Oceansat -3 is expected to be launched in 2020.

Cartosat series –The first satellite, Cartosat - I was launched in 2005 with resolution of 2.5 meters. Then came Cartosat 2 in 2007, 2A in 2008 and 2B in 2010, 2C in 2016, 2D and 2E in 2017, 2F in 2018 and the latest one is Cartosat 3 in 2019. The imaging capability of each is better than the last one. The latest in the series, i.e. Cartosat – 3 can produce scene specific spot image with high resolution of 0.25 meters.

RISAT series – India entered into radar imaging through RISAT – 2 satellite in 2009. The second in the series, RISAT – 1, was delayed and launched 2012. The next in the series was RISAT – 2B and 2BR -1 in 2019 and the latest one in the series is EOS-1 launched in 2020.

INSAT series – INSAT series satellites are advanced meteorological satellites There are two satellite in this series i.e. INSAT – 3D launched in 2013 and INSAT – 3DR launched in 2016.

Other than these, there are few individual special earth observation satellites were launched for specific purposes.

Technology experiment satellite (TES) - Experimental high resolution Technology experiment satellite (TES) launched in 2001.

Megha torpiques- An indo-french satellite mission launched in 2011.

SARAL (Satellite with ARgos and ALtiKa)- Another Indo – France collaboration mission, launched in 2013

HysIS - Hyperspectral imaging satellite launched in 2018.

The Indian earth observation satellite journey is not finished here but has just started. The present observation satellite system with high resolution multi-spectral remote sensing data is delivering data which is not only an asset for the scientific community but also for development of the nation.

 

Reference - 

ISRO website, Department of Space, Indian Space Research Organization, https://www.isro.gov.in/about-isro

Image source - Free-Photos from Pixabay

 

 

Decoding the satellite image - Baitarni Estuary, India.

LISS III image Baitarni Estuary, Odisha

The LISS III satellite image is acquired from Bhuvan portal by National Remote Sensing Centre, ISRO, Government of India, Hyderabad, India.

Decoding the Satellite image -

Google Earth Image of Baitarni Estuary, Odisha

The LISS III image is taken on February 2018. As you can see, it is not a natural colour image. A natural colour image of the same region will not have much brighter colours, like the Google Earth image given here. The hues of the features have the same shades as it is present in the nature. However, it is somewhat difficult to distinguish the features as all the colours merge into each other.

The colourful image i.e. the LISS III satellite image is a false colour composite (FCC). The regular RGB bands are not used in a FCC image, instead other band images are taken. In the FCC image here Red, Green and Infra-red band has been used. The FCC image highlights the features with bright shades which reveal lots of information. LISS III is a multi-spectral sensor employed in ISRO's Resourcesat satellites which capture images in visible and infra-red bands.

In this LISS III image, many distinguishable features in bright shades are visible. One can easily distinguish between the triangular landmass and surrounding water feature in the region by the tone and texture of the features. Another distinguishable feature here is the curvy, meandering bright blue Baitarni river dissecting the landmass. The dissimilar shades of blue in different section is due to presence of suspended particles and sediment brought by the river. As it falls into the Bay of Bengal, the extent of the suspended sediments is clearly visible in different shades of the sea.

Kanika sand island is visible in the Bay of Bengal as bright red patch, east of the main landmass. It is a densely vegetated mangrove forest confirmed by the bright red shade in the FCC. In the mainland, two major and many minor bright red patches are also discernible. The patches are in dissimilar shade/tone of red owing to type, health, and density of vegetation in the region. The two major patches are forested part of the Bhitarkanika national park and wildlife sanctuary. In the northern part of the mainland, cyan/turquiose toned small sized specks of land along the river are the settlements.