Synthetic thinned aperture radiometry (STAR) is a method of

radar Radar is a detection system that uses radio waves to determine the distance ('' ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...

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 A Fourier transform (FT) is a mathematical transform that decomposes functions into frequency components, which are represented by the output of the transform as a function of frequency. Most commonly functions of time or space are transformed, ...

of the brightness temperature map of the scene, and the scene itself is reconstructed by inverting the sampled transform.D. M. Le Vine, Synthetic aperture radiometer systems, IEEE Trans. Geosci. Remote Sensing, vol. 37, no. 12, pp. 2228-2236, 1999. 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 ratio Signal-to-noise ratio (SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to the noise power, often expressed in d ...

for each measurement compared to a filled aperture. Pixel averaging is required for good radiometric sensitivity.

References

Radar Synthetic aperture radar {{science-stub

See also

References