IKONOS, USA

Launched on September 24, 1999, IKONOS is the world's first commercial satellite providing very high resolution (up to 1 m) imagery of the earth. The IKONOS satellite is operated by Space Imaging Inc. of Denver, Colorado, USA. IKONOS simultaneously collects one-meter resolution black-and-white (panchromatic) images and four-meter resolution color (multispectral) images. The multispectral images consist of four bands in the blue, green, red and near-infrared wavelength regions. The multispectral images can be merged with panchromatic images of the same locations to produce "pan-sharpened color" images of 1-m resolution. The satellite camera can distinguish objects on the Earth’s surface as small as one meter square, but it cannot see individual people. The IKONOS satellite is equipped with state-of-the-art star trackers and on-board GPS, enabling it to acquire imagery with very high positional accuracy. The IKONOS imagery is suitable for applications requiring a high level of details and accuracy, such as mapping, agricultural monitoring, resource management and urban planning.

IKONOS Orbit

Type	Sun-Synchronous
Altitude	681 km
Inclination	98.1 deg
Descending node crossing time	10:30 am local solar time
Period	98 min
Off-Nadir Revisit	1.5 to 2.9 days at 40o latitude

Sensor Characteristics

Viewing Angle	Agile spacecraft, along track and across track pointing
Swath Width	11 km nominal at nadir
Image Modes	Single scene: 13 km x 13 km Strips: 11 km x 100 km up to 11 km x 1000 km Image mosaics: up to 12,000 sq. km
Metric Accuracy	12 m horizontal, 10 m vertical without GCP
Radiometric Digitization	11 bits

Spectral Bands	wavelength (µm)	Resolution
1 (blue)	0.40 - 0.52	4 m
2 (green)	0.52 - 0.60	4 m
3 (red)	0.63 - 0.69	4 m
4 (NIR)	0.76 - 0.90	4 m
Panchromatic	0.45 - 0.90	1 m

 

EROS-A1, Israel

Launched on 5 December 2000, EROS-A1 is the first of a planned series of commercial high resolution remote sensing satellites from ImageSat International, an international company formed in 1997. The three main shareholders of ImagSat International are, Israel Aircraft Industries, Ltd. (Israel), Electro Optics Industries, Ltd. (Israel), and Core Software Technology (USA). EROS-A1 collects black and white (panchromatic) images at 1.8 m resolution. The nominal swath width is 12.5 km. The light weight (260 kg) and agile design of the satellite allows it to turn up to 45 degrees in any direction as it orbits, providing the capability to acquire images of many different areas during the same pass. The satellite's agile ability also allows for stereo imaging during the same orbit. The follow-on satellite, EROS-B will have improved resolution of 0.82 m and swath width of 16 km.

EROS-A1 Orbit

Type	Sun-Synchronous
Descending Node Crossing Time	9:45 am local solar time
Altitude	475 - 491 km
Inclination	97.3 deg
Period	94 min

Sensor Characteristics

Viewing Angle	Agile spacecraft along track and across track pointing (up to 45o from nadir)
Sensor Type	CCD
Ground Sampling Distance	1.8 m
Scanning	Asynchronous (up to 750 lines/second)
Radiometric Digitization	11 bits
Spectral Band	Panchromatic, 0.5 - 0.9 µm
Pixels-in-line	7800
Image Modes	Basic Scene: 12.6 km x 12.6 km Monostrips, up to 30o from nadir: Up to 12.6 km x 120 km Monostrips, up to 43o from nadir: Up to 12.6 km x 217 km Image Mosaic: 25.2 km x 25.2 km Stereo Monostrips: Up to 12.6 km x 44 km Stereo Scenes: 12.6 km x 12.6 km

 

QUICKBIRD, USA

Quickbird 2 was successfully launched on 18 Oct 2001

The Quickbird satellites are a series of very high resolution satellites operated by EarthWatch Inc. In September 2001, EarthWatch changed its name to DigitalGlobe. The first of the satellites, Quickbird-1 was launched on 20 Nov 2000, but failed to reach orbit. The second identical satellite, Quickbird-2, is planned to be launched in October 2001. Both satellites were initially planned for 1 m resolution imaging. In December 2000, EarthWatch received a license to operate a 0.5 meter resolution satellite system. The plans for QuickBird 2 are modified to increase the resolution of the satellite imaging system from the originally planned 1-m resolution to 0.61 m by lowering the orbit in which the satellite will be flown. The panchromatic resolution is increased from 1 m to 0.61 µm and the multispectral resolution is increased from 4 m to 2.5 µm.

The Quickbird-2 satellite will simultanelously collect panchromatic images at 0.61 m resolution and multispectral images at 2.5 m resolution. The multispectral images consist of four bands in the blue, green, red and near-infrared wavelength regions. The multispectral images can be merged with panchromatic images of the same locations to produce "pan-sharpened color" images of 0.61 µm resolution. The satelliteµs ability to acquire high-resolution imagery will supply users with satellite data at resolutions comparable to aerial photography. Buildings, cars, and even large individual trees can be recognized. Locational information collected by the satelliteµs star trackers and onboard global positioning system (GPS) will enable users accurate, large-scale mapping without using ground control points (GCPs).

Quickbird-2 Orbit

Type	Sun-Synchronous
Altitude	450 km
Inclination	98 deg
Period	93.4 min.
Off-Nadir Revisit	1 to 3.5 days
Field of Regard	544 km swath

Sensor Characteristics

Viewing Angle	Agile spacecraft, in-track and cross-track pointing +/- 30 deg nominal fore-and-aft and side-to-side, 45 deg maximum
Swath Width	17 km nominal at nadir
Image Strip Length	Up to 225 km
Metric Accuracy	23 m circular error (CE), 17 m linear error (LE) at 90% confidence (without ground control points)
Radiometric Digitization	11 bits

Spectral Band	Wavelength (µm)	Resolution (at nadir)	Resolution (at 30o off nadir)
1 (blue)	0.45 - 0.52	2.5 m	2.9 m
2 (green)	0.52 - 0.60	2.5 m	2.9 m
3 (red)	0.63 - 0.69	2.5 m	2.9 m
4 (NIR)	0.76 - 0.89	2.5 m	2.9 m
Panchromatic	0.45 - 0.90	0.61 m	0.73 m

 

ORBVIEW 3, USA

OrbImage has planned to launch two 1-m resolution satellites. One of the satellites, OrbView-4 was launched on 21 September 2001, but failed to reach orbit. OrbView-4's camera had a 1-m resolution for panchromatic imaging and a 4-m resolution for multispectral imaging. The satellite also carried a hyperspectral imaging instrument. It would have become the first commercial satellite to produce hyperspectral imagery, and the second satellite to have hyperspectral imaging capability (besides the NASA's experimental EO1 satellite).

OrbView-3 satellite is planned to be launched in 2002. It carries the similar 1-m resolution panchromatic and 4-m resolution multispectral imaging instrument, but without the hyperspectral instrument

Orbview-3 Orbit

Type	Sun-Synchronous
Altitude	470 km
Revisit	Less than 3 days

Sensor Characteristics

Swath Width	8 km

Spectral Band	Wavelength (µm)	Resolution
1 (blue)	0.45 - 0.52	4 m
2 (green)	0.52 - 0.60	4 m
3 (red)	0.625 - 0.695	4 m
4 (NIR)	0.76 - 0.90	4 m
Panchromatic	0.45 - 0.90	1 m

 

SPOT 5, France

SPOT 5 is a new satellite of the SPOT family of satellites. It is planned to be launched in the first quarter of 2002. A new High Resolution Geometry or HRG imaging instrument is developed by CNES to be carried on-board SPOT 5. The HRG instrument promises a higher ground resolution than that of the HRV/HRVIR on SPOT 1 - 4 satellites: 5 m, and 2.5 m by interpolation in panchromatic mode, and 10 m in all 3 spectral bands in the visible to near infrared ranges. The spectral band in the short wave infrared band is maintained at a resolution of 20 m due to limitations imposed by the geometry of the CCD sensors used in this band. The field width of HRG is 60 km, same as SPOT 1, 2, 3, & 4. With two HRG instruments, a maximum swath of 120 km at 5 m resolution can be achieved. The oblique viewing capacity is maintained providing rapid access to a given area. A dedicated instrument, High Resolution Stereo (HRS), for along track stereo acquisition will also be carried on board SPOT 5. A VEGETATION large coverage instrument will also be available. To ensure continuity with the SPOT 1 - 4 satellites, the SPOT 5 spectral bands will be the same as those for SPOT 4: B1 (0.50-0.59 µm); B2 (0.61-0.68 µm); B3 (0.79-0.89 µm); and SWIR (1.58-1.75 µm). The panchromatic band will, however, return to the values used for SPOT 1 through 3 (Pan: 0.51-0.73 µm).

SPOT 5 will have the same swath (60 km) as SPOT 1 - 4 satellites, but with higher resolution. In order to transmit the increase volume of data within a data rate limit of 100 Mbit/s, data compression techniques will be used while downlinking the data to the ground station. The specifications of SPOT 5 call for a planimetric accuracy of 10 m (rms) and an elevation accuracy of 5 m (rms). These figures are compatible with conventional mapping standards at 1:50 000 scale. The radiometric quality of SPOT 5 imagery will be equal to or better than that of SPOT 4.

SPOT 5 Orbit

SPOT 5 will have the same orbit as SPOT 1 - 4.

Type	Sun-Synchronous, 10:30 am (local solar time) descending node crossing
Altitude	832 km
Inclination	98.7 deg
Period	101 min
Repeat Cycle	26 days
Off-Nadir Revisit	1 to 3 days

Sensor Characteristics

Swath Width	60 km
Metric Accuracy	10 m (rms) planimetric, 5 m elevation
Radiometric Digitization	8 bits

Spectral Bands	wavelength (µm)	Resolution
1 (green)	0.50 - 0.59	10 m
2 (red)	0.61 - 0.68	10 m
3 (NIR)	0.79 - 0.89	10 m
4 (SWIR)	1.58 - 1.75	20 m
Panchromatic	0.51 - 0.73	5 m (2.5 m by interpolation)

Source : http://www.crisp.nus.edu.sg