IRS 1C Specifications
|Mission Category||Operational Remote Sensing|
|Launch Date Category||December 28, 1995|
|Launch Site Category||Baikanur Cosmodrome Kazakhstan|
|Onboard Power||809 Watts (generated by 9.6 sq.metres Solar Panels)|
|Stabilization||Three axis body stabilized (zero momentum) with 4 Reaction Wheels, Magnetic torquer|
|RCS||Monopropellant Hydrazine based with sixteen 1 N thrusters & one 11N thrusters|
|Payload||Three solid state Push Broom Cameras: PAN (Less than 6 metre solution )LlSS-3(23.6 metre resolution) and WiFS (189 metre resolution)|
|Onboard tape recorder||Storage Capacity : 62 G bits|
|Altitude||817 km Polar Sun-synchronous|
|Local Time||10.30 a.m.|
|Mission Completed||September 21, 2007|
IRS 1C Sensors
Linear Imaging Self Scanning Sensor - 3 (LISS-3)
This sensor is configured to provide imageries in three visible bands as well as in short-wave infrared band. The resolution and swath for visible bands are 23.5 m and 142 km, respectively. The detector is a 6000 element CCD based linear array with a pixel dimension of 10μm by 7 μm. The detector is placed at the focus of a refractive type optical system consisting of eight lens elements, which provides a focal length of 360 mm. The processing of the analogue output video signal is similar to that of PAN. For this camera, a 7-bit digitization is used which gives an intensity variation of 128 levels.
Panchromatic sensor (PAN)
The PAN sensor is configured to provide the imageries of the Earth in visible spectrum, in a panchromatic band (0.5-0.75 m) with a geometric resolution of greater than 10 m and a swath of 70 km. The camera uses an off-axis reflective type optics system consisting of three mirrors for providing the required focal length. A 7μm pixel sized CCD is being used as the detector element. Using three linear array charge-coupled detectors covers the total swath of 70 km and each of these detectors covers a swath of about the central detector is offset from the other two detectors by a distance in focal plane that corresponds to 8.6 km on the ground. The other two detectors cover swath of 24 km each adjacent to the central CCD. These two detectors are aligned with an accuracy of 30 arc sec-1. The overlap of the central swath with the side swaths is 600 m on the ground. Each of the detectors provides four analogue outputs, which are independently processed by video chains, converted to digital and providing a data handling system for formatting. For a PAN data compatible with the expected signal to noise ratio, a 6-bit digitization is used which gives 64 radiometric gray levels. Characteristics of PAN camera Geometric resolution from altitude of 817 km 5.8 m Effective focal length for optics 980 mm Swath 70 km Field-of-view for optics ±2.5o (across track) ±0.3o (along track) Spectral band 0.5-0.75 μm.
Wide Field Sensor (WiFS)
This sensor operates in two bands B3: 0.62 μm to 0.68 μm (Red) and B4: 0.77 μm to 0.86 μm (NIR). Each band uses a 2048 element CCD with an element size of 13 μm by 13 μm. A wide-angle refractive optics system with 8-lens elements is used with a focal length of about 56 mm. This payload required to cover a ground swath of 770 km with a resolution of 188 m. This ground swath with the selected 817 km orbit can provide the required repetivity for the intended application. To cover the 770 km, two separate band assemblies are used for each band. Thus the entire swath in each band is covered by two detectors. Each of the detectors covers half of the swath. The signal processing chain in similar to LISS-3 wherein the analogue video signal is converted to 7 bits and given to data handling system for formatting.
Characteristics of WiFS
- Band 3 0.62-0.68 μm Band 4 0.77-0.86 μm Resolution 188.3 m Swath 810 km
Radiometric resolution 7 bits Band-to-band registration ±0.25 pixel