GeoSTAR at a glance
The Geosynchronous Earth Orbiting Synthetic Thinned Aperture Radiometer (GeoSTAR) is a prototype instrument designed to observe and improve the understanding and forecasting of hurricanes, severe weather and related hydrological-cycle processes. GeoSTAR will provide real time, continuous three dimensional images of atmospheric profiles of air temperature and humidity from a geosynchronous Earth orbit. Operating near 50 GHz and 183 GHz, currently unavailable temperature and water vapor soundings at high temporal and spatial resolution will be provided for the first time.
GeoSTAR launch is expected in 2016 – 2020 timeframe.
Technology and prototype development efforts for GeoSTAR have been underway since 2003. Effort has been led by JPL, in close collaboration with SPRL. SPRL researchers have been developing flight qualified versions of the massively parallel computational signal processing modules that are the central elements of GeoSTAR’s Fourier synthesis image formation capability.
GeoSTAR consists of an array of microwave receivers. A prototype version of the sensor has been developed based on technology that could be scaled up to a flight version. Continuing technology development efforts are currently underway to enhance the capabilities of the sensor – particularly with respect to the spatial and temporal resolution of its three dimensional atmospheric imagery.
Bjorn Lambrigtsen – JPL Principal Investigator
Alan Tanner – JPL System Engineer
Chris Ruf – SPRL Principal Investigator
Engineering Feats of Note
GeoSTAR is a Fourier synthesis microwave spectrometer that measures atmospheric profiles by varying its spectral sensitivity and, hence, its depth of penetration into the atmosphere from above. GeoSTAR varies the horizontal location of the profiles, and thereby produces three dimensional imagery, by software beam steering of a large, thinned array of small antenna elements. The fact that GeoSTAR is able to produce full Earth disk 3-D images with no moving parts – by software beam steering horizontally and spectral tuning vertically – is the key to its accommodation on operational geosynchronous platforms. The custom massively parallel integrated circuit in use by GeoSTAR was designed by the Center for Advanced Microelectronics and Biomolecular Research (CAMBR) at the University of Idaho.
Once completed, GeoSTAR is projected to be able to provide 3-D images of tropospheric and lower stratospheric air temperature and humidity profiles, with 25 – 50 km spatial resolution, that are refreshed every 15-30 minutes. Such fine temporal resolution has never before been possible and is expected to revolutionize the tracking and forecasting of rapidly developing weather systems.