Papers by alberto moreira
IGARSS 2020 - 2020 IEEE International Geoscience and Remote Sensing Symposium
The paper provides an up to date overview of the German TanDEM-X satellite mission status and its... more The paper provides an up to date overview of the German TanDEM-X satellite mission status and its ongoing science activities. In June 2020 TanDEM-X will reach his 10 years of successful operation – a view back and forward will be presented in the final paper. The global digital elevation model (DEM) of TanDEM-X became available in 2016 and surpassed all expectations: It has 99.9% coverage, 12-m posting, absolute height accuracy of approximately 1 m and a relative height error (standard deviation) of 0.8 m. This unique data set has been available since then for commercial and scientific applications. Last year, a low-resolution version of the global digital elevation model with 90-m posting has been released for free download for scientific applications. Since 2017 new interferometric acquisitions have been started with the goal to generate a global change layer which will register all the changes of the Earth topography occurred since the first acquisitions of TanDEM-X. The data collection for the global change layer will be ready by the end of 2020. By that time, it is planned to start a new science phase of TanDEM-X with a focus on interferometric acquisitions over forest, ice sheets and permafrost regions.
Hydroterra was one of the three mission concepts competing for the Earth Explorer 10. The idea of... more Hydroterra was one of the three mission concepts competing for the Earth Explorer 10. The idea of this concept is to placea SAR system into a geosynchronous orbit to measure key processes of the diurnal water cycle. The DLR Microwavesand Radar Institute conducted an airborne SAR campaign to support the Phase 0 study of Hydroterra and gain knowledgeabout geosynchronous SAR data processing, where long integration times are needed to achieve the required azimuthresolution. In this paper the airborne experiment and the simulation procedure are described. The simulated Hydroterra products are demonstrated and analyzed. Additionally, these data are used to generate interferometric products and to evaluate the impact of radio frequency interference
Deutsches Zentrum für Luft- und Raumfahrt (DLR), Nov 1, 2015
Airborne synthetic aperture radar technology and development, antennas, multimodal air-and spaceb... more Airborne synthetic aperture radar technology and development, antennas, multimodal air-and spaceborne SAR signal processing, airborne campaigns for demonstration of new technologies, techniques, and applications Radar Concepts New radar concepts and techniques New sensor concepts, spaceborne SAR mission conceptual design, digital beamforming, bistatic and multistatic systems, traffic monitoring with radar, and information retrieval Satellite SAR Systems Spaceborne SAR missions Spaceborne SAR techniques, system concepts, SAR missions and instrument operations, system engineering and performance, calibration, SAR mission project leadership, and management Reconnaissance and Security Microwave sensors for reconnaissance and security applications SAR data and mission simulation, mission planning, analysis and optimization, inverse SAR, radiometry, signatures, and synthetic aperture radiometry 2 Research and Project Results 2.1 Spaceborne SAR Missions 2.2 Microwaves Systems and Techniques 2.3 Airborne SAR 2.4 Reconnaissance and Security
Precise knowledge of the far-field antenna patterns associated with individual receive channels o... more Precise knowledge of the far-field antenna patterns associated with individual receive channels of a multichannel SAR system is of fundamental importance to operate the radar instrument in advanced imaging modes. A prominent example is Tandem-L which uses a large deployable parabolic reflector that is illuminated by a digital feed array with multiple receive channels. This architecture enables, in combination with an appropriate onboard signal processing, the acquisition of a wide image swath by simultaneously recording multiple scattered radar echoes with a set of narrow elevation beams that are steered in real time towards the angles of the arriving wavefronts. As such a multiple elevation beam technique is prone to range ambiguities, optimized real-time beamformers are considered that maximize their gain in the direction of the desired radar echo and suppress, at the same time, the range ambiguous radar echoes arriving from different angles. The implementation of these advanced r...
The operation of two SAR satellites flying in close formation enables bistatic operation allowing... more The operation of two SAR satellites flying in close formation enables bistatic operation allowing for highly accurate single-pass interferometry. TanDEM-X has been operationally demonstrating this novel technique since 2010. With a typical separation between the TerraSAR-X and TanDEM-X satellites of 120 to 500 m a global DEM with 1 m height accuracy at 12 m posting has been generated. Final DEMs are of consistent homogeneous quality and well within specifications. Tandem-L, a proposal for an innovative L-band SAR mission, is also employing bistatic interferometry aiming at the systematic observation of dynamic processes on the Earth’s surface. Thanks to the novel imaging techniques and the vast recording capacity of up to 8 Terabytes/day, it will provide vital information for solving pressing scientific questions in the biosphere, geosphere, cryosphere, and hydrosphere and will make an essential contribution for a better understanding of the Earth system and its dynamics.
Forests cover about 30% of the Earth’s landmasses, play an essential role in many dynamic process... more Forests cover about 30% of the Earth’s landmasses, play an essential role in many dynamic processes of our planet, and are of extreme importance for all living species, allowing for the existence and preservation of biodiversity and healthy ecosystems. However, severe loss and degradation of forests is nowadays occurring at an alarming rate, hence putting this delicate balance in serious danger. For these reasons, an up-to-date assessment of the forest resource state becomes of crucial importance. In this context, spaceborne SAR represents a very attractive solution for regular mapping and monitoring of forested areas. Indeed, thanks to its weather and daylight independence and large coverage capabilities, spaceborne SAR is able to provide timely, high-resolution imaging at local, as well as regional and up to global scale. In this paper we present the new global Forest/Non-Forest classification map from TanDEM-X interferometric SAR data (InSAR) at X band, at a spatial resolution of...
This work gives reasons for using the selected algorithm for ScanSAR image compression. The algor... more This work gives reasons for using the selected algorithm for ScanSAR image compression. The algorithm is descibed in detail together with experimental results of our detailed study. Results in terms of signal-to-distorsion-noise ratios (SDNR) and phase errors (standard deviation) are compared to results gained upon stripmap SAR images.
Tandem-L ist ein Vorschlag fur eine innovative L-Band-SAR-Mission fur die Umwelt- und Klimaforsch... more Tandem-L ist ein Vorschlag fur eine innovative L-Band-SAR-Mission fur die Umwelt- und Klimaforschung. Das System Erde verandert sich laufend und dynamische Prozesse passieren in verschiedenen Spharen und auf unterschiedlichen Zeitskalen. Tandem-L wurde konzipiert, um ein breites Spektrum von dynamischen Prozessen in adaquaten Zeitintervallen zu beobachten und so dringend benotigte Informationen zur Beantwortung hochaktueller wissenschaftlicher Fragestellungen im Bereich der Bio-, Geo-, Kryo- und Hydrosphare zu liefern. Tandem-L tragt damit entscheidend zu einem besseren Verstandnis des Systems Erde und seiner Dynamik bei.
In this paper we present the global Forest/Non-Forest Map derived from TanDEM-X bistatic interfer... more In this paper we present the global Forest/Non-Forest Map derived from TanDEM-X bistatic interferometric synthetic aperture radar (InSAR) data. The global TanDEM-X dataset has been acquired in stripmap single HH polarization mode and covers a time span from 2011 up to 2016. The volume correlation factor (or volume decorrelation), derived from the interferometric coherence, quantifies the coherence loss due to multiple scattering within a volume, a mechanism which typically occurs in presence of vegetation. For this reason, the volume correlation factor has been used as main indicator for the identification of forested areas. Quicklook images, a multi-looked version of the original full-resolution data at a ground resolution of 50 m x� 50 m, have been used as input for the generation of the global product. The mosaicking process of multiple acquisitions is discussed as well, together with the identification of additional information layers, such as urban areas or water bodies. The re...
We employ data from the second generation of SAR systems, e.g., the Italian COSMO-SkyMed (CSK) co... more We employ data from the second generation of SAR systems, e.g., the Italian COSMO-SkyMed (CSK) constellation, the German TanDEM-X formation and the European Sentinel-1A/B constellation to monitor the characteristics of grounding line migration using short repeat-time interferometry and accurate InSAR DEM in the Amundsen Sea Embayment (ASE), West Antarctica. The ASE is a marine-based ice sheet with a retrograde bed containing enough ice to raise global sea level by 120 cm. Several studies have inferred the mechanical properties of portions of ASE using observationally constrained numerical models, but these studies offer only temporal snapshots of basal mechanics owing to a dearth of observational time series. Prior attempts of grounding lines mapping have been limited because few space-borne SAR missions offer the short-term repeat pass capability required to map the differential vertical displacement of floating ice at tidal frequencies with sufficient detail to resolve grounding l...
2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), 2017
2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS, 2021
The idea of the former Earth Explorer 10 mission Hydroterra is to place a SAR system into a geosy... more The idea of the former Earth Explorer 10 mission Hydroterra is to place a SAR system into a geosynchronous orbit to understand rapid processes of the diurnal water cycle over regions of interest in Europe and Africa. The DLR Microwaves and Radar Institute conducted an airborne SAR campaign to support the Hydroterra mission. Airborne data were collected to simulate the long integration time of a geosynchronous SAR image and to evaluate the potential to detect diurnal moisture changes. In this paper the airborne campaign is described and the achieved results are presented.
2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS, 2021
This paper provides an overview of the German spaceborne radar program starting with the X-band s... more This paper provides an overview of the German spaceborne radar program starting with the X-band synthetic aperture radar (SAR) instrument on board the Shuttle Imaging Radar missions (SIR-C/X-SAR) in 1994, followed by the Shuttle Radar Topography Mission (SRTM) in 2000. The German national satellite radar program began in 2007 with the launch of the satellite TerraSAR-X, which is providing since then high-resolution X-band images for scientific, commercial and governmental applications. TanDEM-X, an almost identical twin, joined TerraSAR-X in 2010 to form the first bistatic SAR interferometer consisting of two satellites in close formation flight. The TanDEM-X mission generated a global, high-resolution digital elevation model of the Earth surface with unprecedented accuracy. The High-Resolution Wide-Swath (HRWS) mission has been approved for realization at the end of 2020. It is a very ambitious multistatic SAR mission exploiting the formation flight of one active main satellite and three smaller passive companion satellites. HRWS implements for the first time in space the novel MirrorSAR concept. As for the current planning, the launch is expected in 2027.
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Papers by alberto moreira