India’s RISAT-1 High Resolution SpotLight (HRS) Polarimetric Image

Indian Space Research Organization’s (ISRO) Radar Satellite-1 (RISAT-1) is a state of the art Microwave Remote Sensing Satellite carrying a Synthetic Aperture Radar (SAR) Payload operating in C-band (5.35 GHz), which enables imaging of the surface features during both day and night under all weather conditions.

Showing RISAT-1  capabilities, ISRO has released few RISAT-1 high-resolution spotLight (HRS) polarimetric image.

1. All India Radio Super Power Transmitter, Bengaluru (Date of Pass:20-May-2014, Look Angle:41.970)

The radar is viewing from left to right. Transmit tower appearing as bright targets and its top is displaced towards the radar from its true position on the ground (called as layover effect). The true position of the tower is appearing as bright cross as marked in the figure.

RISAT-1 High Resolution SpotLight (HRS)Polarimetric Image of All India Radio Super Power Transmitter, Bengaluru ISRO

RISAT-1 High Resolution SpotLight (HRS) Polarimetric Image of All India Radio Super Power Transmitter, Bengaluru
ISRO

The Radar shadows can also be seen in the above image. The height of the tower is computed from the image as 105 m. It was found to match with the actual height.

2. Howrah Bridge, Kolkata, (Date of Pass:2- Apr -2013, Look angle :42.940)

The radar is viewing from right to left. Howrah bridge is a cantilever   bridge appearing as bright target with even and odd polarized returns. Hoogly river is appearing as blackish green due to very low back-scatter and some depolarized return.

RISAT-1 image of Howrah Bridge. Credit: ISRO

RISAT-1 image of Howrah Bridge.
Credit: ISRO

3. Namma Metro Station, Peenya, Bengaluru  (Date of Pass:20-May-2014, Look Angle:41.970) 

The radar is viewing from left to right. The metro station roof is made of fiber material with metallic support structure which is appearing as odd bounce target. The elevated metro corridor is appearing as depolarized target.

RISAT-1 image of Namma Metro Station, Peenya, Bengaluru. Credit: ISRO

RISAT-1 image of Namma Metro Station, Peenya, Bengaluru.
Credit: ISRO

Applications of RISAT-1 Satellite Data

Active Microwave Remote Sensing provides cloud penetration and day-night imaging capability. These unique characteristics of C-band (5.35GHz) Synthetic Aperture Radar enable applications in agriculture, particularly paddy monitoring in kharif season and management of natural disasters like flood and cyclone.

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