What is Synthetic Aperture Radar (SAR) and Its Use in the Space Sector?

 


Synthetic Aperture Radar (SAR) is used to create two-dimensional (2D) images or three-dimensional (3D) reconstructions of objects, such as landscapes. Synthetic-aperture radar uses radar antenna motion over a target area to provide finer spatial resolution than conventional beam-scanning radar. It is usually mounted on moving objects such as spacecraft or aircraft. SAR uses the Doppler Effect to help locate space objects that are outside the normal reach of other radar systems. This type of radar is based on the Doppler Effect and it uses two incoming waves to help determine the speed and direction of movement of the space object.

The first one is a radio wave that travels through the atmosphere at the speed of sound. The reflected signal from the object's surface is then used to generate a synthetic sound frequency that is then amplified many times by the reflector. This way, the Doppler Effect can create a Doppler bounce that can be used to locate the space object. Moreover, SAR systems are very important for the Earth Observation business. SAR satellites are more expensive to develop, and the images are more complex (despite distinct advantages), raising processing costs. Moreover, SAR can balance tens of thousands of pounds and as large as a school bus.

Optical Flow Sensors are used along with the Doppler Effect to determine the distance of the space object from the Earth. This distance is then compared with the position of the satellite in orbit. This technology is currently being used by various organizations. In June 2020, the United States-based company announced that it will launch a constellation of 48 commercial Synthetic Aperture Radar (SAR) satellites across multiple orbits. Moreover, in November 2019, an Italian space company plans to operate a Synthetic Aperture Radar (SAR) satellite for infrastructure monitoring. Furthermore, in February 2020, Singapore unveiled a space-based radar plan that is scheduled for launch to low-earth orbit in 2022. The Synthetic Aperture Radar (SAR) satellite will be used for commercial and military applications.

 

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