Coming Soon:

GeoEye’s Next-Generation Color Satellite Imagery

In the months ahead a commercial Earth imaging satellite, GeoEye-1, will be launched by GeoEye Inc. It will provide the highest resolution and most advanced collection capabilities of any commercial remote sensing system. The satellite will acquire high-quality panchromatic and multispectral imagery at spatial resolutions of 0.41-meters in the panchromatic mode and 1.64-meters in the multispectral mode, respectively, and collect hundreds of thousands of square kilometers of map-accurate imagery in a single day.

By Kevin Corbley

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Once launched GeoEye-1 will be equipped with the most advanced technology ever used in a commercial remote sensing system.  The satellite will be able to collect images at 0.41-meter panchromatic (black & white) and 1.65-meter multispectral resolution.  As shown in the following simulation using IKONOS satellite imagery (a) and aerial photography (b), the detailed
half-meter imagery will expand the applications for satellite imagery in every commercial and government market.

A Team of Partners

To bring about such a major endeavor, GeoEye president and CEO Matthew O'Connell assembled a team of partners to develop and launch GeoEye-1. Gilbert, Arizona-based General Dynamics/Advanced Information Systems serves as the prime contractor and integrator for the satellite's bus and telescope. To develop a camera capable of acquiring imagery at 41-centimeter spatial resolution (16 inches), GeoEye turned to ITT, formerly Kodak Remote Sensing Systems, which also built the IKONOS sensor. The satellite will be lifted into orbit on a Boeing Delta II launch vehicle from Vandenberg Air Force Base in California. Following the launch of GeoEye-1, the satellite will undergo about 45-60 days of calibration and checkout. Once the satellite is declared operational, it will begin a three-month imaging operation mostly dedicated to meeting the needs of the Pentagon’s National Geospatial-Intelligence Agency (NGA). For the most part, imagery collected during this period will also be made available in the company archive for commercial sale. GeoEye will take commercial orders during this timeframe and fulfil them as soon as possible. While GeoEye-1 will be able to collect imagery at 41-centimeter ground resolution, imagery for commercial customers will be re-sampled to half meter resolution before sale. This is due to current U.S. government licensing restrictions. However, GeoEye is seeking a waiver to their license in order to be able to provide the highest resolution imagery to governmental customers in some countries. For example, in the European region, GeoEye has requested that Poland be able to have direct access to GeoEye-1 and governmental customers there be able to utilize 41-centimeter imagery.

 

On June 29, 2007, the National Oceanic and Atmospheric Administration (NOAA) notified all U.S. commercial imagery providers that the 24 hours hold rule for imagery better than the resolution of the IKONOS satellite (.82-meter) has been lifted. This licensing restriction was originally created early in the history of the commercial remote sensing industry. This will enable space-based commercial imagery providers to sell imagery from current and next generation satellites immediately upon collection. 

 

As shown in this simulation using IKONOS satellite imagery (a) and aerial photography

(b), the half-meter imagery will even be able to discern home plate on a baseball diamond.

Mapping in Orbit

“The GeoEye-1 satellite fundamentally will be a mapping machine in orbit,” explains Mark Brender, GeoEye's vice president of communications and marketing. “We will be able to offer commercial customers half-meter resolution color imagery with the most accurate geo-location accuracy ever achieved in a com­mercial space-based system,” he said. GeoEye recently acquired M.J. Harden, an aerial imaging and geospatial firm in Mission, Kansas. The firm flies two aircraft, one with a digital mapping camera, and the other with a new LiDAR imaging system. “The combination of aerial and satellite imagery will be a powerful tool for mapping and surveying,” Brender said. In June of this year GeoEye invested in a privately held company called Spadac. Spadac utilizes geospatial technologies in doing predictive analytics. GeoEye is working closely with Spadac in offering customers the tools to help them take pixels to the next level. Says Brender, “Spadac helps us extract knowledge from our pixels and aids our customers in better understanding issues before they become problems.”

Advanced Capabilities

As a major customer, NGA will receive priority tasking and a substantial discount for agreeing to purchase a large volume of imagery. But ample capacity will be dedicated to commercial customers and allow the company to build a vast archive of imagery in relatively short time. “Spatial resolution, geo-location accuracy, and large-area coverage are the three specifications commercial and government customers are most interested in,” says Dave Kenyon, GeoEye senior director, space segment engineering. “And those are the key capabilities we focused on when building this satellite.” Of course, resolution is the parameter by which most judge and compare imaging satellites. Frank Koester, vice president and director, Commercial and Space Science Program, ITT Space Systems Division, says, “ITT's integrated camera payload, including telescope and sensor subsystem, will provide GeoEye-1 with the highest resolution in commercial remote sensing.” Offering 41-centimeter panchromatic and 1.64-meter multi-spectral in the blue, green, red, and near-infrared bands, the satellite will enable clients to identify small objects and features at a level of detail never available before from commercial imaging satellites. At that resolution, you can count the manholes on a city street or discern home plate on a baseball diamond. Geo­spatial data users in the defense and intelligence, oil and gas, insurance, urban planning, utility, and cartographic disciplines- all of which traditionally map small features-are expected to expand their use of satellite imagery as a result. It's anticipated that online search engines such as Yahoo!, Google Earth, and Microsoft Virtual Earth also will be anxious to import consistent high resolution color imagery over large areas. In addition, though satellite and aerial images often are complementary, GeoEye expects many traditional users of aerial imagery to jump to satellites for applications requiring half-meter resolution, especially in parts of the world where it's difficult to deploy an aircraft due to weather, political, or security issues. But there's more to good imagery than spatial resolution, notes Lee Demitry, GeoEye's vice president of engineering. “People are going to be stunned with the sharpness and clarity of this imagery,” he predicts, explaining that overall image quality, most often defined by the sharpness of feature boundaries, is just as critical as spatial resolution to many applications. The camera builder, ITT, has employed new technological advancements to achieve this level of image quality. “The large size of the telescope's primary mirror, the alignment of the camera telescope, and a favorable (high) signal-to-noise ratio are key design elements in ultimately producing high-quality imagery.” Geo-location accuracy is another imaging capability GeoEye expects will appeal to end users across all market segments. This refers to the precision with which objects in an image can be mapped relative to their absolute location on earth's surface. GeoEye-1 will offer three-meter accuracy, which means end users can map natural and manmade features in stereo to within three meters of their actual locations without ground control points. This level of geo-location accuracy will be achieved with the help of three onboard systems: a GPS receiver, gyroscope, and star tracker, which will enable the satellite to determine its precise attitude, position, and location at all times. Such ancillary data will be transmitted along with image data back to earth for the ground segment to use in processing the imagery. Some of these systems, such as the star tracker, have never flown on commercial satellites before and were only used on U.S. government imaging satellites. Adds Demitry, “The ability to map features with this level of horizontal accuracy without any ground control is for commercial satellites and will be a huge advantage- and enormous cost savings-for any cartographic application.”

Prodigious Imagery

The third major technological advancement found in the GeoEye-1 satellite will be its ability to collect an enormous amount of imagery. In the panchromatic mode, the satellite will be capable of collecting up to 700,000 square kilometers in a single day and in the multispectral mode 350,000 square kilometers per day. This volume of data collection-more than four times that of any other existing commercial imaging platform-will be made possible by the agility of the satellite itself. “The entire satellite will be able to turn and swivel quickly in orbit to point the camera telescope at areas of the Earth directly below it, as well as from side to side and front to back,” explains GeoEye's Kenyon. “This agility will enable it to collect much more imagery during a single pass.” According to Mike Greenwood, spokesperson for General Dynamics Advanced Information Systems, the agility is made possible by “enhanced reaction wheels that provide the torque required for motion yet inject little jitter or smear into the imagery.” The standard image swath width will be 15.2 kilometers, but GeoEye-1 will be able to swivel and collect multiple adjoining swaths on a single pass, meaning that very large contiguous areas can be imaged at one time. This is ideal for large-scale mapping requirements, especially for emergency response and disaster relief. The agility also means GeoEye can satisfy more than one client during a single pass by collecting a variety of individual scenes in the same geographic region. The satellite will swivel up to 40 degrees off nadir, giving it an effective revisit rate of less than three days. GeoEye has already announced plans to put the large-area imaging capability to work in filling its archive. The company says it will collect as much land imagery as possible on every pass and store it in the archive whether there is a tasking order for the scenes or not. Announcement of GeoEye-1's imaging specifications has elicited responses from both the commercial and private-sector imagery markets. Ed Jurkevics, a remote sensing industry consultant and principal analyst at Chesapeake Analytics in Arlington, Virginia, singles out the large-area imaging. “GeoEye-1 will be able to deliver imagery over large areas in a relatively short and reasonable time. So clients can expect to receive a complete image map over a large area such as a country in one season rather than over many months,” he said. “This will be especially important for EU countries in mapping out agricultural yields and measuring the size of land parcels,” added Jurkevics. He explained that for large-area mapping projects, fast acquisition improves the overall success. If too much time elapses between collections of contiguous scenes, for example, changes in ground conditions such as vegetative growth or soil moisture can adversely impact correlations made among the scenes. The accuracy of digital elevation model extraction from image pairs can degrade if the image pairs were collected at different times under different conditions. Defense and Intelligence. For government applications, especially those involving the defense and intelligence communities, the large-area coverage combined with the 41-centimeter spatial resolution has spurred the greatest anticipation for the new satellite, according to Jim Lewis, director of the Technology and Public Policy Program at the Center for Strategic and International Studies (CSIS) in Washington, D.C. Lewis says GeoEye-1 will help take pressure off U.S. Department of Defense satellites because it will provide data for many of their applications, partly because its spatial resolution and coverage area may approach the same capabilities as classified imaging systems. “In the defense/intelligence community, you have competition for assets, so they have to prioritize which mission comes first,” he explains. “Being able to go outside those government assets and get a commercial system that can provide you things on a much faster basis can only help. And the government rides on the investment made by Wall Street in commercial remote sensing. Lewis adds that commercial imaging systems receive tremendous support from the U.S. Department of Defense because their images aren't classified. Although this may sound counterintuitive, military agencies often favor unclassified information, including satellite imagery, because it can be shared more freely with allies and coalition partners or nongovernmental organizations. Security concerns aren't an issue with commercial satellite imagery. Under the development expertise of GeoEye and its key suppliers, the company has upgraded a centralized command and control facility at its headquarters in Dulles, Virginia. This operations center will send tasking and operating commands to the satellite and receive data downlinks from it. Three other stations will be operated or leased by GeoEye in Alaska, Norway, and Antarctica. Regardless of location, GeoEye-1 customers will be able to see what's available for sale easily. The company recently enhanced its existing archive search tool, known as ImageSearch, to allow clients to perform online searches of the IKONOS archive. They expect to be able to deliver images to a client shortly after collection by the satellite.That scenario should come soon, as the GeoEye-1 team anxiously anticipates the launch of its satellite that should expand the reaches of satellite imagery and remote sensing for the government, commercial customers, and the public.

Kevin Corbley is a principal with Corbley Communications in Winchester, Virgina. Graphic illustration and images courtesy of GeoEye. For more information on this subject visit www.geoeye.com.