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. RISAT-1 was successfully launched by PSLV-C19 on April 26, 2012. It started beaming images from 01 May 2012. On the first day the satellite imaged from Gangotri Uttarakhand to Narasimharajapura of Karnataka covering cities like Bhopal , Akola Sikandara Latur, Shimoga Etmadpur etc.The trace is shown in Figure 1. The first day data was captured successfully at the IMGEOS facility of NRSC at Shadnagar. The data productsare released to the users after the initial phase calibration and evaluation. RISAT is the first of the type with Synthetic Aperture Radar payload. Radar backscatter depends upon the sensor parameters such as frequency, polarization and incidence angle as well as on target parameters such as dielectric constant, roughness and geometry. The SAR on RISAT will operate in C band with both horizontal and vertical polarization. The SAR sensor is based on active phase array antenna technology and it provides electronic agility for achieving multimode imaging capability.
RISAT - 1 carries a multimode C- band (5.35 GHz) Synthetic Aperture Radar (SAR) as the payload. The choice of C- band frequency of operation and RISAT - 1 SAR capability of imaging in HH,VV,HV,VH and circular polarizations will ensure wide applicability in the thrust areas like flood mapping, Agriculture & crop monitoring, generic Vegetation, Forestry, Soil Moisture, Geology, and Sea Ice and Coastal applications etc. As it is a side looking active sensor , around 107 Km of either side of the sub -satellite track comes under Non Imageable area for the orbit under consideration. ( Figure2)
Imaging Geometry and modes of operation
In the absence of the emergency/user request the default mode of collection will be MRS descending, left looking , with dual polarization with a repeat cycle of 25 days. The data can be acquired in all weather conditions, in both ascending (Evening) and descending mode (Morning) and in both right look and left look.
Online Browse, User Order Processing Facility and Payload Programming Facility
Online browse facility is available online from 01 Jul 2012 and the search is based on the meta information for the options like – Point, polygon, Shape file, Date range are available to search the metadata. Sample Data Products for various modes are provided on NRSC web site. Using Online user order processing facility Users can place order on line at their end. The order processing system handles the entire chain of selection of data to procedure of delivery. Online payload programming facilityEnables users to request for future collections, which will be planned after clash analysis with other requests
Data Format Documents
Sample Data Products
|CRS||120 MB||193 MB||278 MB||-|
|CRS Level 2A||120 MB||193 MB||-||-|
|MRS||120 MB||193 MB||193 MB||-|
|MRS Level 2A||120 MB||193 MB||-||-|
|CFRS1||193 MB||193 MB||193 MB||193 MB|
|FRS1||193 MB||193 MB||193 MB||193 MB|
|FRS Level 2A||120 MB||193 MB||-||-|
This image demonstrates the potential of RISAT-1 SAR data for 3-D visualization applications. This image is an anaglyph - a stereoscopic image, composed of superposition of two images of same area acquired in different view angles. In this anaglyph, right image coded in red color is superposed on the left image in blue or green color combine to produce a three-dimensional effect when viewed with a pair anaglyph glasses. The two images involved were captured by The RISAT-1 SAR in its Fine Resolution Scan (FRS-1) image mode of 3m spatial resolution over Dharamsala, Himachal Pradesh. The scenes were acquired on 07-Jan-2013 and 22-Mar-2013 with different look angles, respectively, of -33.7 and -43.4 degrees. Download Anaglyph can be viewed with a pair of 3-D glasses with a red and blue filter covering each eye. They work by filtering light from the image, so that each eye receives only one color. The following links shows how to make 3-D glasses.
Enhanced Terrain Geo Referenced
An improved version of currently operational RISAT-1 Level-2 Terrain corrected Geo-Referenced Product named as "Level-2A Enhanced Terrain corrected Geo-Referenced Product" is added to existing data products list. Though Level-2 and Level-2A are geometrically at par in planar regions, Level-2A product has significant improvement of geo location accuracy in hilly regions and is available for Imaging Modes FRS-1, MRS and CRS for Linear and Circular polarizations. This new Level-2A product is provided in map projected domain in CEOS & GEOTIFF format. Two more auxiliary files for Layover mask and Local Incidence angle are also available along with the files already defined for RISAT-1 Level- 2 product. This product uses the True height values even in highly undulating terrains. Read more on Geometry related aspects of Level-2A product. Sample images of RISAT-1 Level-2 Terrain Geo- Referenced Product, its layover mask image along with Enhanced Terrain Geo- Referenced image are illustrated below:
Level -2 Terrain
Damboor Lake, Tripura
Faridabad City Full More
The image demonstrates the potential of RISAT-1 SAR data for various 3-D visualization applications including Geological / Geomorphological Applications. The micro geomorphological variations especially disposition river terrace, slope morphology, landslide morphology, slope cuttings, break in slope etc can be better understood which is useful for applied geological studies like geo-hazard, geo-engineering & geo environmental applications.