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Advanced Imaging Magazine

Updated: January 12th, 2011 10:01 AM CDT

Eye in the Sky

Latest Canadian SAR satellite delivers higher resolution, more flexibility
RADARSAT-2
© Canadian Space Agency and MacDonald, Dettwiler and Associates
RADARSAT-2 is a second-generation Synthetic Aperture Radar (SAR) satellite with a number of advancements, including three-meter ultra-fine beam for high-resolution imaging and increased data storage.
A RADARSAT-2 image of Greenland.
© Canadian Space Agency and MacDonald, Dettwiler and Associates
A RADARSAT-2 image of Greenland.
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By Barry Hochfelder

All the systems and interfaces necessary to operate and maintain the satellite and support the SAR payload are in the bus module. This includes systems that support attitude measurement and control, telemetry and command, data storage and retrieval, power generation and storage, and thermal control.

The satellite payload, which operates in the C-band, includes the SAR antenna and associated sensor electronics for imaging. The payload is a microwave instrument that transmits and receives signals through clouds, haze, smoke and darkness. Active microwave imaging provides significant advantages in monitoring the earth under conditions that would preclude observation by aircraft or optical satellites.

The phased-array antenna is composed of hundreds of miniature transmit-receive modules. Fully computer-controlled, the antenna can be steered electronically over the full range of the swath and can switch between operating modes in seconds.

When in orbit, the satellite is exposed to extreme temperature fluctuations that range from minus-170C to plus-150C, so the satellite is protected by thermal blankets of Mylar, a heating system and mirrors. The structure is made of composite material and features special insulation.

How It Works

A pulse is sent out of the SAR antenna. It travels to earth and reflects back to the satellite, much the way a policeman's radar bounces from your car back to him. That's the simple version.



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