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The concept of a passive receiving small satellite flying in formation with an active satellite for bistatic Synthetic Aperture Radar (SAR) imaging has been the subject of numerous national and international studies. In 2013, ESA received an offer from the National Commission for Space Activities of Argentina (CONAE) to launch a small satellite with the SAOCOM-1b satellite, and to collaborate during...
In recent years SAR Polarimetry has become a valuable tool in space-borne SAR based sea ice analysis. This work compares the polarimetric backscatter behavior of sea ice in space-borne X-band C-band and L-band Synthetic Aperture Radar (SAR) imagery. Two sets of spatially and temporally near coincident fully polarimetric acquisitions from the TerraSAR-X/TanDEM-X, RADARSAT-2 and ALOS-2 satellites are...
The Soil Moisture Active Passive (SMAP) mission was launched January 31st, 2015. It is designed to measure the soil moisture over land using a combined active / passive L-band system. Due to the Aquarius mission, L-band model functions for ocean winds and salinity are already mature and may be directly applied to the SMAP mission. In contrast to Aquarius, the higher resolution and scanning geometry...
This paper presents the design and preliminary performance tests of an L-band synthetic aperture interferometic radiometer using the new sampling concept of clock scan. With the advantages of simple and deployable array structure, the concept of Clock Scanning Microwave Interferometric Radiometer (CS-MIR) has much potential to apply for the future Solar Polar Orbit (SPO) and Geostationary Earth Orbit...
SMAP and SMOS have been successfully providing L-band brightness temperature (Tb) since 2015 and 2011, respectively [1, 2]. Since both missions provide Low Earth Orbit observation at the same frequency, inter-calibration of brightness temperatures measured from these two missions leading to a consistent Tb record is critical in order to have consistent and reliable science datasets. For a radiometer,...
In this paper, we present a method for fusing different frequency synthetic aperture radar (SAR) images for improving the accuracy of land subsidence estimation using differential interferometric SAR (DInSAR) technique. Our study area, Kansai International Airport, Osaka, Japan, consists of two landfilled islands, and the subsidence velocity of an island is much larger than that of the other one....
BelSAR is an ESA funded project for acquiring and analyzing airborne bistatic Synthetic Aperture Radar data at L band, in support of the SAOCOM passive radar satellite under study at the agency. MetaSensing has built two L band SAR systems able to work in bistatic mode. A few test flights have been performed in The Netherlands and the paper reports the first results of the airborne bistatic campaign.
Characterizing, understanding, and projecting changes in atmospheric methane and terrestrial water storage require information about wetland dynamics, which remains a major gap in existing knowledge. Despite recent advances in satellite monitoring techniques, dynamic wetland mapping needs to be improved for more accurate global inventories and also to monitor variabilities at sub-km scale over multiple...
A new space-borne mission based on a multi-channel microwave radiometer in the frequency range 0.5–2 GHz as been recently approved by the Italian Space Agency for a preliminary concept study. The innovative instrument will be devoted to the study of the Cryosphere and in particular on sea ice volume, ice sheet temperature and soil status. Scientific objectives and first mission concept are presented...
Large amounts of RFI(Radio Frequency Interference) are observed in the data obtained over East Asia, North America and Europe by L-band missions of SMOS, Aquarius and SMAP etc. Multiple approaches have been proposed to detect and eliminate the RFI signals in the past few decades. This paper focuses on a new potential RFI detection and mitigation method that is based on the Local Outlier Factor (LOF)...
The objectives of this research are to (1) address remote sensing strategies and requirements for estimating snow depth and snow water equivalent (SWE) using existing L-Band interferometric data sets in coordination with field-based observations and modeling frameworks and, with this information, (2) inform the Next Generation Cold Land Processes Experiment (SnowEx) toward articulating the appropriate...
In this paper, a dual-frequency permafrost active layer thickness (ALT) retrieval algorithm is presented wherein P-band AirMOSS and L-band UAVSAR data are used to retrieve the layered soil dielectric constants and layer thicknesses. Using the known radar calibration accuracy, radar sensing depth is defined to help understand the limit of radar backscatter sensitivity to subsurface soil conditions...
This paper presents a comprehensive reappraisal of the scattering, both backscattering and bistatic scattering, and emission of rough soil surface predicted by a well-established theoretical model, the advanced integral equation model (AIEM). Extensive numerical data simulated by approximate and numerically exact models as well as experimental datasets of well-characterized bare soil surfaces were...
The European Space Agency's SMOS and NASA's SMAP soil moisture remote sensing satellite missions do not perform well in several agricultural regions. For example, we have found that SMOS and SMAP soil moisture retrievals are 0.09 to 0.07 m3 m−3 lower, respectively, than an in-situ soil moisture network in one such agricultural region in Central Iowa, USA. We hypothesize that this dry bias is in part...
This paper introduces the operational status of the Advanced Land Observing Satellite-2 (ALOS-2) and its follow-on L-band SAR mission in Japan. ALOS-2 observes the earth surface with the Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) that is effectively used for many applications such as land deformation mapping and forest change mapping. To keep and enhance the applications using...
In 2016, the Advanced Land Observing Satellite-2 (ALOS-2, “DAICHI-2”) observed various disaster affected areas. Japan Aerospace Exploration Agency (JAXA) operated the emergency observation more than hundred times in the year. The Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) aboard ALOS-2 contributed for detecting the disaster affected area, ground deformation and flood affected area...
SAR remote sensing has been expected as an efficient rice crop monitoring tool due to its flexible operability with wide swath. Though many researchers have intensively analysed the backscatter, there still exist non-negligible mysteries to extract physical parameters. To solve the problems, it is essential to conduct theoretical characterization of experimentally obtained radar backscatter from rice...
ALOS-2 ScanSAR data was used for examining the effect of precipitation and soil moisture variations on L-band forest backscatter in tropical regions. Multitemporal data spanning from observation cycle 39 to 62 acquired over tropical forests in South America and Africa has been used. Precipitation data provided through JAXA's global rainfall watch was used to examine the temporal change of L-band σ...
ALOS-2/PALSAR-2 25-m spaced global mosaic has been produced as the L-band SAR forest monitoring dataset selected from the best acquisitions over the global land and year 2014 and 2015, as the resume of the dataset after pausing the ALOS/PALSAR on 2011 April 22, in the end of 2015. Detailed evaluation results showed some image degradations compared to ALOS/PALSAR: visible stripes across the neighboring...
The purpose of this paper is to investigate how SAR Tomography (TomoSAR) can be used to estimate ground polarimetric covariances in forest scenarios in order to increase the amount of information that can be extracted from SAR data stacks is beyond the vertical reflectivity profiles. Under the hypothesis of a two-layer model composed by ground and volume contributions, an algorithm is proposed that...
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