SAR Boosts Imagery Power

Written by Peter Buxbaum

GIF 2010 Volume: 8 Issue: 2 (March)

 

The use of synthetic aperture radar (SAR) imagery in Haitian relief efforts has underscored the growing importance of this technology for a variety of defense, intelligence and humanitarian missions.

Moving quickly to help the earthquake-devastated nation, the National Geospatial-Intelligence Agency in January issued task orders to all three of the contractors awarded an indefinite delivery/indefinite quantity contract for commercial satellite synthetic aperture radar (COMSAR) imagery only the month before.

“The task orders we recently issued to support operations in Haiti were focused on acquiring imagery of certain areas of the country to detect changes,” said Laura Gentry, international commercial program manager for COMSAR at NGA. “The user of the imagery wanted to see what buildings looked like before, versus after, the earthquake.”

U.S. Southern Command had requested the imagery from NGA through the Department of State, which is the lead agency coordinating relief efforts. The unusual move of awarding task orders to each of the three vendors under the COMSAR contract was to “allow us to be flexible,” said Gentry. “Our job is get data for end-users. It depends on when satellites are available. Each satellite makes only one pass per day, so with more vendors and satellites working the job, you get more access to the geography that is needed.”

The Haiti disaster relief efforts are representative of the growing demand in the use of synthetic aperture radar for intelligence imagery and mapping. The data that will be provided under the latest COMSAR contract will enable NGA to provide other government and Department of Defense agencies improved information acquisition capabilities, particularly in bad weather and low light conditions.

Synthetic aperture radar is a system that utilizes two frequencies, X-band and T-band. “SAR can be deployed in space,” said Ed Kaminski, director of radar imagery for EADS North America, one of NGA’s COMSAR contractors. “The satellite collects reflected radar energy and downlinks that information, where a processor generates images of various resolutions and quality depending on the tasking to the satellite mission. These images can be used for a number of different applications.”

SAR can also be deployed on an airborne platform. “We deploy SAR on a Gulfstream jet that cruises at 36,000 feet and 450 miles per hour,” said Ed Saade, president of Fugro EarthData. “The X-band reflects off the tops of trees or buildings, while the T-band frequency can penetrate the canopy or the forest to give better earth information.”

The recent NGA contract was for satellite-based SAR and was awarded to MDA Geospatial Services, EADS North America and Lockheed Martin Space Systems. The contracts include a five-year ordering period with a ceiling of $85 million.

NGA routinely procures commercial imagery from both domestic and foreign sources, said Karyn Hayes Ryan, NGA’s director for commercial imagery data. “NGA is the DoD functional manager for geospatial intelligence,” she explained. “We purchase and disseminate imagery on behalf of our customers. Customers also have access to imagery that sits in our libraries.”

NGA’s main customers for SAR data include combatant commands, intelligence agencies, special operations such as Haiti disaster relief, and the Federal Emergency Management Agency. “NGA and its mission partners utilize commercial SAR data for intelligence, military and homeland security applications,” said Ryan. “NGA procures both satellite and airborne SAR. The latest contract improves NGA’s ability to provide intelligence in low light and bad weather conditions.”

GEO-LOCATION ACCURACY

NGA and EADS North America had an earlier 18-month contract during which NGA evaluated data delivered by EADS’s commercial TerraSAR-X radar satellite, which has been in orbit since 2007 and fully operational since early 2008.

“Results have exceeded expectations and demonstrated superb geo-location accuracy,” said Andreas Kern, director of business development and sales at InfoTerra, a company related to EADS. Studies conducted and published by NGA have confirmed these results, he added.

InfoTerra and EADS North America have a common parent company. InfoTerra has the exclusive license and rights to the data derived from EADS SAR satellites.

The recent SAR contract is a commercial acquisition and is based upon what contractors show on their commercial price lists, according to Gentry.

“The data that we purchase is specifically related to requirements we receive from users,” she said. “Delivery times for the data depend on the technical capabilities of the contractors, the requirements we have received, and how quickly the data would be required.” “Lockheed Martin has partnered with e-GEOS of Italy for this important initiative, and the team is now focused on providing commercial satellite SAR data, products and services that meet NGA’s customers’ needs,” said Bill Meersman, vice president for surveillance and intelligence systems at Lockheed Martin Space Systems.

Lockheed Martin Space Systems and e-GEOS will provide imagery from the Italian COSMO-SkyMed satellites that will be used in a wide range of U.S. government applications.

“The COSMO-SkyMed satellite system is a dualuse system intended for both civil and military applications funded by the Italian Space Agency and the Italian Ministry of Defense,” Meersman explained. “The system is designed to operate using four satellites with synthetic aperture radar sensors.” The first three satellites are already in orbit, while the fourth will be launched later this year.

“These satellites are capable of operating day and night in all atmospheric conditions, and with frequent revisit times,” said Meersman. The constellation can revisit locations every six hours at mid-latitudes when operating with four operational satellites.

The COSMO-SkyMed constellation can provide images with a resolution as high as one meter, Meersman said, and has the capacity to record up to 2.4 million square kilometers per day to be used for security applications, ground surveillance, environmental monitoring and natural resource management by public sector bodies and industry.

EADS North America will be supplying imagery from TerraSAR- X, an EADS synthetic aperture radar satellite, along with related products and direct downlink services. The satellite was built by Astrium, an EADS-related company. During the current five-year contract period, TerraSAR- X will be complemented with another EADS Astrium-built SAR satellite, TanDEM-X, which is scheduled to be launched later this year.

Together the two will create a twin-satellite formation that will collect data for a global digital elevation model “with greater accuracy than has been available before,” said Corrinne Kaplan, an EADS North America vice president. But since the second satellite has not yet been launched, a precise analysis of its performance has yet to take place, she added.

“The SAR instruments on TerraSAR-X and TanDEM-X enable large-area coverage, as well as extremely high resolution and geolocation accuracy—performance that is particularly well suited for reconnaissance and intelligence applications,” Kaplan explained. “Data and products supplied under this contract can be used in processing centers of DoD agencies and the U.S. intelligence community, as well as downlinked directly to ground receiving facilities. Satellite images, fused with other intelligence and geospatial information, deliver actionable information to national decision makers and warfighters.”

NGA’s Ryan has perceived an increased demand for SAR imagery for applications such as disaster relief. “Since this is commercial data and unclassified, it is more sharable with first responders,” she said. “First responders are responding by acquiring the infrastructure to support SAR.”

SAR is particularly useful for first responders dealing with natural phenomena such as hurricanes, Gentry noted. “SAR imagery is playing an increasingly important role in these situations because it can penetrate the cloud cover,” she said. “That is one of its big benefits. First responders can use the imagery for flood monitoring, change detection, or assessing a possible housing crisis, even though the area is completely cloud covered.”

Maritime surveillance and monitoring oil spills are two other emerging SAR applications.

REGIONAL MAPPING

Fugro EarthData provides SAR imagery primarily for large regional topographic surface mapping, according to Saade. The company has provided imagery to NGA and has done work for governments such as that of Papua New Guinea, a nation without much detailed topographical mapping before, as well as on commercial projects such as oil and gas pipelines.

“We fly a lot in jungle and equatorial type of environments, and get five meter resolution,” Saade said. “That’s not as good as LiDAR, but it’s better than nothing.”

LiDAR, or Light Detection and Ranging, uses 1.064 nanometer wavelength lasers to provide resolutions of one point per meter on the ground and one point per 15 centimeters vertically. Airborne LiDAR is generally deployed on propeller aircraft flying at a much lower altitude than Fugro’s jet aircraft, Saade noted, which means that the LiDAR collection activities are subject to vagaries in the weather and cannot capture nearly as wide swaths of geography as can SAR. In addition, LiDAR cannot penetrate a jungle canopy.

“We recently worked on a commercial oil and gas pipeline project in Peru,” said Saade. “They had to put the pipeline in difficult terrain. We succeeded in providing our customers with a baseline about how to route the pipeline.”

Fugro EarthData is in the process of updating its current SAR system, which was developed in 2002 and 2003. “We will be taking advantage of more modern technologies in electronics and computing power,” he said. “We are also looking at using lighter and more fuel-efficient aircraft. We want to take advantage of everything we’ve learned in the last 10 years.”

Even more important than updating technologies, said Saade, Fugro EarthData will be offering SAR for a wider variety of applications. That development has been fueled primarily by demand from the company’s customers, he noted.

“As more people are exposed to SAR, they get more and more ideas about how to use it for mapping and other purposes,” said Saade. “It is important for us to get out of there in front of potential customers who have new ideas about how to use SAR.”

NGA’s Ryan has seen recent developments in the sophistication of the algorithms used is SAR systems, which enhance in the processing of the data and help advance SAR applications such as change detection. But, she emphasized, it is not NGA’s role to develop future systems. “We acquire what is available now as opposed to developing new capabilities,” she said.

The current five-year contract with EADS, MDA and Lockheed, Ryan noted, is an effort to move away from stand-alone contracts and toward a scheme that would allow NGA to optimize its exploitation of commercial SAR resources.

“We can look and see who is available to collect the imagery being sought by our customer,” she explained. “Then we can explore what delivery timelines the contractors make and what the cost to the government will be. Then we try to negotiate for the best price and performance timeline.

“Our customers have varying needs and we feel this is the most efficient way to manage the acquisition of these images,” she added. “Sometimes we only need to get one image. At other times, as in the relief operations in Haiti, we want to get them all.” ♦

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