1607009.pptx

India’s first indigenous radar satellite

RISAT-1

It can spy and do a hundred humdrum things

RISAT-1 •Radar satellite-1 (RISAT-1) is a state of art of the 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 condition’

What is satellite? • A satellite is an object in

space that orbits or circles around a bigger object. There are two kinds of satellites: natural (such as the moon orbiting the Earth) or artificial (such as the RISAT-1 orbiting the Earth). • The concept of satellite is based on circular motion. • The centripetal force is supplied by gravity of earth. • Orbital altitude of Risat-1 is 536 km.

RISAT-1 Mission

• CbandSAR • Launched on April 26, 2012 from Sriharikota, INDIA

• Satellite Mass: 1851 kg • Launch Vehicle : PSLV C-19 (XL Version)

MAJOR FEATURES OF RISAT -1 (SAR)

CENTRALIZED PAYLOAD CONTROL

C-BAND SYSTEM 5.35 GHz

BAQ IMPLEMENTATION MULTIPLE CHIRP BANDWIDTHS & HIGH SPEED DIGITIZATION

SINGLE/DUAL/ QUAD/CIRCULAR POLARIZATION

MULTIMODE SYSTEM ACTIVE ANTENNA TECHNOLOGY INCIDENT ANGLE INDEPENDENT SWATH AND O

RISAT-1 Satellite • Stabilized, 1851 kg mass • 1800w power & 70AH Ni H Battery • 640 Mbps Data Rate (320 Mbps RHCP, LHStar Sensors & 0.05 deg pointing3-Axis • CP) & 240 Gb SSR • Truncated Triangular Prism / Cuboid structure

RISAT-1 orbits

What is Remote sensing ? "Remote sensing is the science (and to some extent, art) of acquiring information about the any surface without actually being in contact with it. ” Microwave Remote Sensing. Electromagnetic radiation in the microwave wavelength region is used in remote sensing to provide useful information about the Earth's atmosphere, land and ocean.

A microwave radiometer is a passive device which records the natural microwave emission from the earth.

What is C-band?

C Band is the original frequency allocation for communications satellites. C-Band uses 3.7-4.2GHz for downlink and 5.925-6.425Ghz for uplink. The lower frequencies that C Band uses perform better under adverse weather conditions than the Ku band or Ka band frequencies.

What is Synthetic Aperture RADAR ? • SAR is a active Microwave remote sensor capable of operating any time in all weather conditions like both day and night, through clouds, rains, haze, dust, fog, smoke. • SAR overcomes limitations of the optical remote sensors which can collect data only in clear weather and good illumination conditions. • In active microwave remote sensing, the scattering characteristics of the target can be derived from the radar cross section (back scattering coefficient, σ0) calculated from received power, antenna parameters and the physical characteristics of the target.

OPERATION MODES OF RISAT1 - SAR

L=R(λ/l ) Where, L=length of virtual antenna R=distance from object to satellite l=length of real antenna λ= wavelength of microwave

536 km

(C)FRS1/ (C)FRS2 MODE (C)HRS MODE

(C)CRS MODE (C)MRS MODE

Fine Resolution Stripmap mode-1

Fine Resolution Stripmap mode-2

Scan SAR Mode

High Resolution Spot mode

RISAT IMAGE QUALITY PARAMETERS Single Pol Dual Pol HH/HV/V HH+HV/ V/VH VV+VH High Resolution Spotlight Mode (HRS) Fine Resolution Stripmap Mode-1 (FRS-1) Fine Resolution Stripmap Mode-2 (FRS-2)

Circular Polarimetry TX: CP Rx: V and H

Quad Pol HH+HV+VV+VH

1-2 m resolution, 10 x 10 Km (10x100 km- Sliding Spot ) Spot o= -16 dB 3-6 m resolution 25 Km swath o= -17 dB 6m resolution 25 Km swath o= -20 dB

Medium Resolution ScanSAR Mode (MRS)

25 m resolution,115 Km swath o= -17 dB

Coarse Resolution ScanSAR Mode (CRS)

50 m resolution 223 Km swath o= -17 dB

9-12 m resolution 25Km swath o= -19dB

RISAT-1 Mission Status • Initial characterization completed including coverage over Amazon for calibration • Data being regularly received at Shadnagar GS of NRSC & successful test download at Tromso,Northern Norway • Early valuation studies completed, users have demonstrated polarimetry applications with RISAT-1 • FRS, MRS & CRS Mode data released to users • Operational projects like flood inundation mapping and rice mapping have been given multi-date data sets

SAR Applications • • • • • • • • • •

Defence Floods Agriculture Oceanography Snow and Glacier Soil Moisture Geology Forestry Oil Slick/ Seepage Urban Studies

RISAT-1 Data Acquisition

For border nevigation

Use for internal sequrity

Kolkata

Namma metro station ,Bengluru

Rice Mapping RISAT–1/ MRS 2 date composite Oct 25, Nov 19, 2012

Sivaganga Area of Tamil Nadu showing Samba rice area (cyan colour)

Flood Mapping (Bihar,2012) RISAT-1; Bihar- 20 Sep 2012

Flood Inundation

• RISAT-1 ScanSAR-MRS mode - 18 m. • HH & HV polarized images acquired .

Flood Map

Flood Mapping (Lakhimpur, Assam, 2012) RISAT-1 Image of Assam-16 September 2012

Flood Inundation

RISAT-1 MRS mode - 16th September 2012

Flood Map

Oil Spill

RISAT-1 HYBRID POLARIMETRYRESULTS

Andaman Sea

Andaman Sea

Pali, Rajasthan

SABARMATI

Antarctica

OIL SPILL, NORWAY

Tunisia

Sea Ice

AHMEDABAD

Coastal Bathymetry using RISAT-1 FRSSAR around north of Mumbai

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