Ikonos (1999)


Washington DC
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Pushbroom Imaging System

The system is based on a new optical system: a push-broom camera with a 10 m focal length, which has been folded into two meters through the use of a mirror. It is supposed that this telescope will resolve terrestrial object less than 1 meter as it passes 680 km at nadir at the speed of 7 km per second. This satellite was designed to take both panchromatic images with one-meter resolution and multispectral images with four-meter resolution. Additionally, a near-infrared band at four-meter resolution is imaged.

The entire satellite will be able to pivot in orbit to collect cross-track imagery coving a distance of 725 km at either side of the ground track. Due to the satellite's 680 km altitude, imagery will maintain at least a one-meter ground sample distance (GSD) for 350 km to either side of nadir, or a 700 km swath of at least one meter imagery.

The system is designed to carry three GPS antennas and three digital star trackers to maintain precisly camera station's position and attitude. A rigid satellite platform was built to reduce the virbation of platform and to contribute the integrity of the line-of-sight determination. The satellite will be rotating around the Earth in a sun synchronous polar orbit, which will allow it to traverse the planet every 98 minutes, crossing the equator at the same time (ca. 10.30 am ) in every orbit.

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Specs:

1. General Information
Corporation "System" Name Space Imaging 
Imagery Type Pushbroom 
Payload  ~ 225 - 275 kg 
Model Panchromatic Multispectral
Pixels 11 bit 11 bit

2. Orbit Information
Flying Height 680 km 
Inclination (deg) 98.1(deg) (Sun synchronous) 
Repeat visite  14 days (Max) 
Repeat Cycle  1-3 days (Max) 
Period (rev/day)  14.6 

3. Processing Information
Scene (max) Process 600/day 
On board recording 64 GB 
Delivery time from Acquisition to User  24 hr. - 48 hr.
Ground Station Sites  Denver, Alaska, Japan + Regional affiliates 

4. Sensor Information
Swath width (km)  11 by 11 
Field of view (FOV)  0.93 
Stereo imaging  In & Cross track 
Sensor position  GPS 
Sensor attitude  3 Star trackers 
Pointing in track Cross track 45 
Resolution at Nadir Panchromatic Multispectral
Resolutions 0.82m 4m
Spectral band widths 0.45-0.9 0.45-0.52
0.52-0.60
0.63-0.69
0.76-0.90
Kodak 1m Resolution Space Camera:


Launch Date -  April 27, 1999
Launch Vehicle - Athena II
Launch Vehicle Manufacturer - Lockheed Martin
Launch Location - Vandenberg Air Force Base, California
Resolution - Ground resolution of each band:
1-meter panchromatic (nominal at <26deg off nadir)
4-meter multispectral  (nominal at <26deg off nadir)

Imagery Spectral Response:
Pan
0.45 - 0.90 microns
Multispectral
1: Blue 0.45 - 0.52
2: Green 0.52 – 0.60
3: Red 0.63 - 0.69
4: Near IR 0.76 - 0.90

Swath Widths & Scene Sizes:
Nominal swath width: 13 km at nadir
Areas of interest:
a nominal single image at 13 km x 13 km
strips of 11km x 100 km up to 11 km x 1000 km image mosaics of up to 12,000 sq. km. up to two 10,000 square kilometer contiguous areas in a single pass within a region

Metric Accuracy:
12-meter horizontal and 10-meter vertical accuracy with no ground control 2-meter horizontal and 3-meter vertical accuracy with ground control
These are specified as 90% CE (circular error) for the horizontal and 90% LE (linear error) for the vertical.

Orbital Information:
Altitude 423 miles / 681 kilometers
Inclination  98.1 degrees
Speed 4 miles per second / 7 kilometers per second
Descending nodal crossing time 0:30 a.m. (IKONOS 1) or 1:30 p.m. (IKONOS 2)
Revisit frequency 1.5 days at 1-meter resolution;
1 day at 1.5-meter resolution (using single satellite - the frequency will improve with two satellites)
Orbit time 98 minutes
Orbit type sun-synchronous
Viewing angle Agile spacecraft - in-track and cross-track pointing
Weight 1600 pounds

Kodak 1m Resolution Space Camera
Developed for Thornton, Colorado-based Space Imaging EOSAT, the imaging payload will enable IKONOS 1 to collect panchromatic (gray-scale) image data of Earth to one-meter resolution; and multi-spectral data (red, green, blue, and near infrared) to 4 meter resolution.

The ability to resolve objects on the ground as small as one meter in diameter represents a tenfold increase in existing image resolution quality from what has been previously available. The imagery will possess five foot location accuracy on the ground, enabling geographic information system (GIS) users to plot highly accurate 1:2400 scale maps, among other applications

The space camera's electro-optical assembly consists of a lightweight telescope, a focal plane array, and a data compressor–all designed and manufactured by Kodak. The telescope's mirrors were finished to atomic-level smoothness using a proprietary polishing technique known as ion figuring.

Using this computer-controlled process, Kodak opticians shaped the telescope's 28 inch diameter primary mirror so perfectly that if it were enlarged to 100 miles in diameter, you could drive that distance and not hit any bumps higher than eight-hundredths of an inch. The weight of the primary mirror was reduced by cutting a honeycomb pattern into its core using abrasive waterjet technology, and fusing thin mirror plates to each face.

http://www.kodak.com/US/en/government/ias/heritage/ikonos.shtml

spaceimaging.com