Microwave interferometric radiometry in remote sensing: An invited historical review

Abstract

The launch of the Soil Moisture and Ocean Salinity (SMOS) mission on 2 November 2009 marked a milestone in remote sensing for it was the first time a radiometer capable of acquiring wide field of view images at every single snapshot, a unique feature of the synthetic aperture technique, made it to space. The technology behind such an achievement was developed, thanks to the effort of a community of researchers and engineers in different groups around the world. It was only because of their joint work that SMOS finally became a reality. The fact that the European Space Agency, together with CNES (Centre National d'Etudes Spatiales) and CDTI (Centro para el Desarrollo Tecnológico e Industrial), managed to get the project through should be considered a merit and a reward for that entire community. This paper is an invited historical review that, within a very limited number of pages, tries to provide insight into some of the developments which, one way or another, are imprinted in the name of SMOS.

Higher-Order Moving Target Detection for Rotating Scanning Synthetic Aperture Interferometric Radiometer

“…FOV = R λ / Δu = 1364 m (14) In our simulation, the polarization direction of antennas is assumed to be fixed during the array rotation, which can be achieved by the rotation of antennas regularly with the array rotation. The initial angle θ a0 is set as 0.…”

“…Millimeter wave synthetic aperture interferometric radiometer (SAIR) is a powerful passive detection system for high-resolution surveillance and has been used in various applications [11][12][13][14]. Since the SAIR passively receives the target natural radiation, it can effectively overcome the influence of absorbing material, achieving stealth target detection.…”

“…Since the SAIR passively receives the target natural radiation, it can effectively overcome the influence of absorbing material, achieving stealth target detection. Among the SAIRs, the Rotating Scanning SAIR (RS-SAIR) with linear sparse array is a popular system with low redundancy and high reliability [14][15][16][17][18][19]. By rotating the linear sparse array, RS-SAIR uses fewer antennas to achieve the high-resolution and large field of view (FOV) imaging observation.…”

Salinity from space

“…The measurement requirements of high spatial resolution, which necessitates a large antenna, and a wide swath, to provide good spatial coverage and higher temporal resolution, led ESA to develop an interferometric synthetic aperture passive microwave sensor. This was based on an aperture synthesis technique used in radio astronomy, where a large number of smaller antennae are used to synthesise a larger antenna (for a detailed description see Martín‐Neira et al ., ). In November 2009 ESA launched the SMOS mission with an interferometric synthetic aperture microwave radiometer consisting of 69 small antennae on three Y‐shaped arms (see Figure ).…”

Investigating the potential benefit to a mesoscale NWP model of a microwave sounder on board a geostationary satellite

“…Bizzarri, 2000;Bizzarri and Mugnai, 2002;Gasiewski et al, 2003). While pioneering projects like GOMAS (Geostationary Observatory for Microwave Atmospheric Sounding; Bizzarri, 2000) were based on sounding technologies similar to the ones used for low earth orbiting (LEO) satellites, the latest studies are focused toward synthetic aperture interferometric radiometry (Martín-Neira et al, 2014). Active research is ongoing on this subject with several concepts under investigation: the GeoSTAR (Geostationary Synthetic Thinned Aperture Radiometer) and the GeoMAS (Geostationary Millimeter-wave Array Spectrometer) instruments on board the PATH (Precision and All-Weather Temperature and Humidity) mission under study in the United States (e.g.…”