Synthetically thinned aperture radar
Encyclopedia
Synthetic Thinned Aperture Radiometry (STAR) is a method of radar in which the coherent product (correlation) of the signal from pairs of antennas is measured at different antenna-pair spacings (baselines). These products yield sample points in the Fourier transform of the brightness temperature map of the scene, and the scene itself is reconstructed by inverting the sampled transform. The reconstructed image includes all of the pixels in the entire field-of-view of the
antennas.
The main advantage of the STAR architecture is that it requires
no mechanical scanning of an antenna. Using a static antenna simplifies the antenna system dynamics and improves the time-bandwidth product of the radiometer. 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 for each measurement compared to a filled aperture. Pixel averaging is required for good radiometric sensitivity.
antennas.
The main advantage of the STAR architecture is that it requires
no mechanical scanning of an antenna. Using a static antenna simplifies the antenna system dynamics and improves the time-bandwidth product of the radiometer. 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 for each measurement compared to a filled aperture. Pixel averaging is required for good radiometric sensitivity.
See also
- RadarRadarRadar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
- BeamformingBeamformingBeamforming is a signal processing technique used in sensor arrays for directional signal transmission or reception. This is achieved by combining elements in the array in a way where signals at particular angles experience constructive interference and while others experience destructive...
- Synthetic aperture radarSynthetic aperture radarSynthetic-aperture radar is a form of radar whose defining characteristic is its use of relative motion between an antenna and its target region to provide distinctive long-term coherent-signal variations that are exploited to obtain finer spatial resolution than is possible with conventional...
- MIRASMicrowave Imaging Radiometer with Aperture SynthesisMicrowave Imaging Radiometer with Aperture Synthesis is the major instrument on the Soil Moisture and Ocean Salinity satellite . MIRAS is a planar antenna composed of a central body and three telescoping, deployable arms, in total 69 receivers on the Unit...
, an example of a spaceborne STAR