NATO Multimedia continues its Science series by focusing on the use of high-altitude balloons equipped with the latest radar equipment that quickly assess large areas during disasters.
"What flies higher than an airplane but lower than a satellite? What can save money, fuel, and lives? A balloon," the intro reel for "NATO and Science - Radar on Board a Stratospheric Balloon" inquired. The episode features researchers sponsored by the North Atlantic Treaty Organisation working together with the University of Pisa in Italy and the University of New South Wales in Australia. The NATO Science also supports the project for Peace and Security Program.
High-Altitude Balloons: A Cost-Effective Surveying Solution
Marco Martorella, a professor of radar systems from the University of Pisa in Italy, explains that when there is a need to quickly observe a large area, such as during disasters like floods or forest fires, there are usually few (and most expensive) solutions available. Airplanes are unfortunately ill-equipped for the task, with their limited field of view and capacity to only fly up to 18,000 meters high. Additionally, fuel and other related operational costs further make it unsuitable for surveying large areas.
On the other hand, satellites are situated much higher in the atmosphere, allowing them to cover large areas. However, they are not available on-demand as operators will have to wait for them to position over the location of interest, not to mention the associated costs of using satellites.
To find a solution that covers the need for quick and real-time observational data with feasible costs - scientists turn to stratospheric balloons. They are more cost-effective and easily deployable. Fitted with an imaging system, these balloons can offer an overview of an area covering hundreds of square kilometers.
"The balloon can be thrown by hand and rise to an altitude of 20 to 40 km," Martorella explains. He adds that stratospheric winds - or those that blow 10 to 30 miles above Earth's surface - carry the balloons on a straight path, making their trajectory easy to predict and monitor.
Synthetic Aperture Radars on Stratospheric Balloons
Martorella additionally explains that the high-altitude balloons provide observational data through a technology called Synthetic Aperture Radar. Conventional radar systems require a very large antenna to create large, high-resolution images, making it impractical for high-altitude balloons.
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To work around this problem, scientists devised the synthetic aperture radar that employs many low-resolution images taken rapidly over a period of time. These large number of low-resolution images are collated to generate a larger, high-resolution image. The data is then located and recovered with a GPS-equipped automatic opening parachute once the balloon completes its mission.
The NATO and Science Program
NATO, the intergovernmental alliance between about 30 countries from Europe and North America, also supports a community of scientists to help solve security-related challenges in keeping its member-states safe in a changing world. Through its NATO Science series, it brings some of its projects to the public's appreciation and understanding.
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