The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Long-range mechanically rotating weather radar systems currently in use suffer from inherent performance limitations including coarse resolution, long update time and beam blockage. More importantly their long-range sensing approach prevents sufficient monitoring of the lower troposphere below a height of 1 km. Social significance of such a lack of capability extends up to hinder a timely reaction...
Maritime environment, and in particular the sea clutter, has a significant impact on the detection efficiency. Therefore the physical properties of the radar sea clutter must be well mastered. In this paper, we focus on sea clutter data acquired during an experiment called MARLENE, which was held in the Mediterranean Sea region of Toulon, France, in 2014. The aim of this experiment was to characterize...
In the maritime boundary layer, air-sea interaction processes have an important impact on radar propagation. The radar range performance near the sea surface depends on meteorological and sea surface conditions. Strong gradients of humidity and temperature close to the air-water interface are most often the reason for propagation effects such as ducting. For ship borne radars the evaporation duct...
In this contribution the role of the atmosphere on space-borne synthetic aperture radar (SAR) systems is revisited in some detail and reviewed together with a first step towards a quantitative assessment of the effects of the atmosphere on the wideband signals phase.
In the framework of Germany and France cooperation, a specific experiment called MARLENE has been carried out in the Mediterranean sea region off Toulon, France, in spring 2014. It aims at characterizing sea environmental influence on electromagnetic wave propagation and sea backscattering for Refractivity From Clutter (RFC) and radar Doppler detection. Environment measurements and characterization...
Propagation above the sea surface depends on many parameters related to the meteorological and oceanographic conditions, the measurement geometry and the system parameters. In this contribution we report on an experiment performed at the Gulf of Mexico in 2012. A dataset consisting of measurements from a 94 GHz radar system above the sea surface towards a fixed corner reflector was established in...
This contribution reports about experimental activities during the 2011 Squirrel campaign in the Baltic Sea, where a number of in- and outbound runs of the Mittelgrund research vessel were measured by the Fraunhofer FHR MEMPHIS Radar in sea configuration at both Ka and W band. Aboard the employed vessel, four corner-reflectors (CR) at different heights in forward and backward direction where mounted...
The results of a propagation experiment with measurements above the sea surface during September 2011 in the frame of the Squirrel campaign are shown. For the experiment, MEMPHIS, a highly versatile radar developed at Fraunhofer FHR (former FGAN) was applied to perform a number of measurements towards a point target (corner reflector) located at the Bookniseck site over a pathlenghts of nearly 8 km...
Helicopter collision avoidance sensors require all weather and day and night performance. Radar fulfills these conditions. To be able to see also cables and other small scale structures, millimeter wave radar is a favourite candidate for this task. To be able to develop adequate collision avoidance algorithms, a data base of relevant background signatures has to be available. Measurements with a 94...
In this paper we propose some ionospheric correction schemes for space-borne synthetic aperture radar (SAR) and polarimetric interferometric SAR (PolInSAR). The spatial and temporal variation of the free electron density in the upper-most atmosphere affects the propagation of the radar pulse resulting in image distortions. We estimate the total electron content (TEC) by applying the Appleton-Hartree...
SIGNAL is an innovative earth exploration mission proposal with the main objective to estimate accurately and repeatedly topography and topographic changes associated with mass change or other dynamic effects on glaciers, ice caps and polar ice sheets. Elevation measurements are complemented with glacier velocity measurements, providing valuable additional information for a better understanding of...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.