IRS-P6
The RESOURCESAT-1 (IRS-P6) is envisaged as the continuity mission to IRS-1C/1D, with enhanced capabilities both in the payload and the platform, to meet the increasing demands of the user community. The objectives of the mission are :
* To provide continued remote sensing data services on an operational basis for integrated land and water resources management at micro level, with enhanced spectral and spatial coverage and stereo imaging.
* To further carry out studies in advanced areas of user applications like improved crop discrimination, crop yield, crop stress, pest/disease surveillance, disaster management etc.,.
The life of the mission is planned to be five years. The satellite was launched by the indigenously built Polar Satellite Launch Vehicle on October 17, 2003. The orbit parameters of IRS-P6 are same as IRS-1C.
Orbits/cycle |
341 |
Semi major axis |
7195.11 km |
Altitude |
817 km |
Inclination |
98.69 deg |
Eccentricity |
0.001 |
Number of orbits/day |
14 |
Orbital period |
101.35 minutes |
Repetivity |
24 days |
Distance between adjacent paths |
117.5 km |
Distance between successive ground tracks |
2820 km |
Ground trace velocity |
6.65 km/sec |
Equatorial crossing time |
10.30 A.M (at descending node) |
The payload system of IRS-P6 consists of three solid state cameras :
1. A high resolution multispectral sensor - LISS-IV
2. A medium resolution multispectral sensor - LISS-III
3. An Advanced Wide Field Sensor – AWiFS
LISS-IV Camera
The LISS-IV camera is a multispectral high resolution camera with a spatial resolution of 5.8m at nadir. The sensor consists of three linear odd-even pairs of CCD arrays, each with 12000 pixels. The odd and even pixel rows are separated by 35 microns, which correspond to five scan lines. Also the placement of the three CCDs in the focal plane is such that their imaging strips on the ground are separated by 14.25 km in the along-track direction.
This camera can be operated in two modes : Mono and Multi-spectral. In the Multi-spectral mode, data are collected in three spectral bands -
0.52 to 0.59 microns (Green (Band 2))
0.62 to 0.68 microns (Red (Band 3))
0.76 to 0.86 microns (NIR (Band 4))
In the multispectral mode, the sensor provides data corresponding to pre-selected 4096 contiguous pixels, corresponding to 23.9km swath. The 4K strip can be selected anywhere within the 12K pixels by commanding the start pixel number using electronic scanning scheme.
In Mono mode, the data of full 12K pixels of any one selected band, corresponding to a swath of 70km, can be transmitted. Nominally, Band-3 data are transmitted in this mode.
The LISS-IV camera has the additional feature of off-nadir viewing capability by tilting the camera by +/- 26deg. This way it can provide a revisit of 5 days for any given ground area.
Major specifications of LISS-IV camera
IGFOV (Across track) |
5.8 m |
Ground sampling distance |
5.8 m |
Spectral Bands |
B2, B3, B4 |
Swath |
23.9 km (multispectral mode)
70 km (Mono mode) |
Saturation radiance
(mw/cm 2 /sr/micron) |
B2 - 55
B3 - 47
B4 - 31.5 |
Integration time |
0.877714 msec |
Quantization |
10 bits
Selected 7 bits will be transmitted by the data handling system |
No. of gains |
Single gain (Dynamic range obtained by sliding 7 bits out of 10 bits) |
LISS-III camera
The LISS-III is a multi-spectral camera operating in four spectral bands, three in the visible and near infra-red and one in SWIR region, as in the case of IRS-1C/1D. The new feature in LISS-III camera is the SWIR band (1.55 to 1.7 microns), which provides data with a spatial resolution of 23.5m unlike IRS-1C/1D (the spatial resolution is 70m).
Major specifications of LISS-III camera
IGFOV |
23.5 m |
Spectral Bands |
B2, B3, B4 and B5 |
Swath |
141 km |
Saturation radiance
(mw/cm 2 /sr/micron) |
B2 28-31
B3 25-38
B4 27-30
B5 6.9
|
Integration time |
3.32 msec |
Quantization |
7 bits SWIR band has 10 bit quantization, selected 7 bits out of 10 bits will be transmitted by the data handling system |
No. of gains |
4 |
AWiFS Sensor
The AWiFS camera provides enhanced capabilities compared to the WiFS camera on-board IRS-1C/1D, in terms of spatial resolution (56 m Vs 188m), radiometric resolution (10 bits Vs 7 bits) and Spectral bands (4 Vs 2) with the additional feature of on-board detector calibration using LEDs. The spectral bands of AWiFS are same as LISS-III.
The AWiFS camera is realized in two electro-optic modules viz.,. AWiFS-A and AWiFS-B, each containing four band assemblies. A combined swath of 740 Km is realized by mounting the two modules on the Deck, with their optical axes tilted by 11.94 deg away from the + yaw axis in opposite direction. With this mounting, a side lap of 128 pixels i.e., about 7.2kKm, is available in the combined swath.
Major specifications of AWiFS sensor .
IGFOV |
56 m (nadir)
70 m (at field edge) |
Spectral Bands |
B2, B3, B4 and B5 |
Swath |
740 km (combined)
370 km each head |
Saturation radiance
(mw/cm 2 /sr/micron) |
B2 - 53
B3 - 47
B4 - 31.5
B5 - 4.64
|
Integration time |
9.96 msec |
Quantization |
10 bits |
No. of gains |
16 |
On-Board Solid State Recorder (OBSSR)
In addition to the three sensors, the satellite carries an OBSSR for collecting data outside the vicinity of the ground stations. The OBSSR has a capacity of 120 Gb. It can record data of 18 minutes.
Products
LISS-III Products
S.No |
Product Type |
Level Of Correction |
Area Covered (km x km) |
No Of Bands |
Output Type |
1 |
Path-Row based *(with & without shift) product |
i.Standard
ii.Geo Referenced |
141 x 141
141 x 141 |
3
4
4 |
Photographic
Digital
Digital |
2 |
**Floating Quadrant product |
Standard
Geo-referenced
|
70 * 70 |
3
4
4 |
Photographic
Digital
Digital |
3 |
+ Mapsheet based product |
Geocoded |
28 x 28
(15' x15') |
3
4 |
Photographic
Digital |
* Shift : Scene can be shifted along the track from 10 % to 90 % of the scene size in steps of 10 %.
** Quadrant : Twelve quadrants, similar to IRS-1C/1D
+ Geocoded : Map sheet / Floating |
LISS-IV products
S.No |
Product Type |
Level Of Correction |
Area Covered (km x km) |
No Of Bands |
Output |
1 |
Scene based |
Standard
Geo Referenced |
23 x 23
70 x 70
23 x 23
70 x 70 |
3 Mx bands
Mono
3 Mx bands
Mono |
Photographic / Digital
Digital / Photographic
Digital
Digital |
2 |
Mapsheet based |
Geocoded
|
7.5' x 7.5'
7.5 'x 7.5'
15' x 15'
|
3Mx bands
Mono
Mono |
Photographic / Digital
Photographic / Digital
Photographic / Digital |
3 |
Point based |
Geocoded |
5' x 5' |
3 Mx bands
Mono |
Photographic / Digital
Photographic / Digital |
4 |
Basic stereo pair |
Radiometrically corrected |
70 x 70 |
Mono |
Digital |
5 |
LISS-3+LISS-4 ( Mono )
Geocoded |
Merge |
15'x 15'
70 x 70 |
3
3 |
Photographic / Digital
Photographic / Digital
|
AWiFS Products
S.No |
Product Type |
Level Of Correction |
Area Covered |
No Of Bands |
Output Type |
1 |
Path-Row based (with & without shift) product |
Standard
Geo referenced
|
370 x 370
740 x 740
370 x 370
740 x 740 |
3
4
4
4
4
|
Photoproduct Digital
Digital
Digital
Digital |
2 |
Map sheet based |
Geocoded |
1° x 1° |
3
4 |
Photographic
Digital |
