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Synthetic-aperture radar (SAR) is a form of radar that is used to create two-dimensional images or three-dimensional reconstructions of objects, such as landscapes. [1] SAR uses the motion of the radar antenna over a target region to provide finer spatial resolution than conventional stationary beam-scanning radars.
The NASA-ISRO Synthetic Aperture Radar (NISAR) mission is a joint project between NASA and ISRO to co-develop and launch a dual-frequency synthetic aperture radar on an Earth observation satellite in 2025. The satellite will be the first radar imaging satellite to use dual frequencies.
Space-based radar or spaceborne radar is a radar operating in outer space; orbiting radar is a radar in orbit and Earth orbiting radar is a radar in geocentric orbit. A number of Earth-observing satellites , such as RADARSAT , have employed synthetic aperture radar (SAR) to obtain terrain and land-cover information about the Earth .
Although the program had been considered for termination by DoD due to what had seemed to be a lack of results, that first success ensured further funding to continue development leading to solutions to those recognized needs. First successful focussed airborne synthetic aperture radar image, Willow Run Airport and vicinity, August 1957.
Furthermore, aperture thinning reduces the overall volume and mass of the antenna system. A disadvantage is the reduction of radiometric sensitivity (or increase in rms noise) of the image due to a decrease in signal-to-noise ratio for each measurement compared to a filled aperture. Pixel averaging is required for good radiometric sensitivity.
Future Imagery Architecture (FIA) was a program awarded to Boeing to design a new generation of optical and radar imaging US reconnaissance satellites for the National Reconnaissance Office (NRO). In 2005 NRO director Donald Kerr recommended the project's termination, and the optical component of the program was finally cancelled in September ...
The associated resolution loss from sharing the synthetic aperture among different swaths is compensated by collecting radar echoes with multiple displaced azimuth apertures. A possible drawback of multichannel ScanSAR or TOPS approaches is the rather high Doppler centroid, [ 9 ] which is one of the most important parameters need to be ...
The radar system required about 80 hours to collect one complete aperture of high-resolution, fully polarimetric data. Its peak power was at 500 kW with a pulse repetition frequency of 40 Hz, and the average transmitted power was about 20 mW. Creating the radar image required the railSAR to limit the Fourier processing to very small patches ...