Paul Snoeij

German Aerospace Center (DLR), Köln, North Rhine-Westphalia, Germany

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Publications (80)51.84 Total impact

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    ABSTRACT: The paper provides an overview of the Copernicus Sentinel-1 system capabilities and applications. In particular, the characteristics of the Sentinel-1 SAR imaging modes and their key performance parameters are described. In addition, the Sentinel-1 SAR interferometry (InSAR) capabilities, especially for TOPS InSAR and the strategy for maintaining the orbital baseline as well as the requirements for TOPS image co-registration are discussed.
    No preview · Conference Paper · Jul 2014

  • No preview · Conference Paper · Nov 2013
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    ABSTRACT: The ESA Sentinels constitute the first series of operational satellites responding to the Earth Observation needs of the EU-ESA Global Monitoring for Environment and Security (GMES) programme. The GMES space component relies on existing and planned space assets as well as on new complementary developments by ESA. In contrast to SAR systems already existing in C-band like ASAR/ENVISAT or RADARSAT-2, high demands on the radiometric stability and accuracy are made for Sentinel-1. The mission depends on the method of calibrating the entire Sentinel-1 system in an efficient way. This paper describes the strategy and provides a plan of all activities required for in-flight calibration of Sentinel-1.
    No preview · Conference Paper · Sep 2013
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    ABSTRACT: The paper provides an overview of the GMES Sentinel-1 system characteristics including the SAR imaging modes and their key performance parameters as well as the specifics of related attitude and orbit control modes (i.e. roll steering mode and zero-Doppler steering mode). In addition, the Sentinel-1 SAR interferometry (InSAR) capabilities are discussed. Furthermore, the paper outlines the planned Sentinel-1 commissioning phase activities related to the in-orbit SAR system calibration and end-to-end performance verification.
    No preview · Conference Paper · Apr 2013
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    ABSTRACT: The ESA Sentinels constitute the first series of operational satellites responding to the Earth Observation needs of the EU-ESA Global Monitoring for Environment and Security (GMES) programme. The GMES space component relies on existing and planned space assets as well as on new complementary developments by ESA. In contrast to SAR systems already existing in C-band like ASAR/ENVISAT or RADARSAT-2, high demands on the radiometric stability and accuracy are made for Sentinel-1. The mission depends on the method of calibrating the entire Sentinel-1 system in an efficient way. This paper describes the strategy and provides a plan of all activities required for in-flight calibration of Sentinel-1.
    No preview · Article · Sep 2012 · Proceedings of SPIE - The International Society for Optical Engineering
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    ABSTRACT: Two Block Adaptive Quantization (BAQ) algorithms considered for implementation on-board Sentinel-1, the Entropy Constrained BAQ (ECBAQ) and the Flexible Dynamic BAQ (FDBAQ) are investigated with real data acquired by TerraSAR-X. The two algorithms are compared with respect to the resulting signal-to-quantization-noise ratio (SQNR) and the compression rate. The results confirm the improved performance of FDBAQ to be expected for Sentinel-1 compared to the more conventional ECBAQ.
    Preview · Conference Paper · Jul 2012
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    ABSTRACT: The ESA Sentinels constitute the first series of operational satellites responding to the Earth Observation needs of the EU-ESA Global Monitoring for Environment and Security (GMES) programme. The GMES space component relies on existing and planned space assets as well as on new complementary developments by ESA. This paper describes the Sentinel-1 mission, an imaging synthetic aperture radar (SAR) satellite constellation at C-band. It provides an overview of the mission requirements, its applications and the technical concept for the system.
    No preview · Conference Paper · Jul 2012
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    ABSTRACT: In the frame of the Global Monitoring for Environment and Security (GMES) Space Component programme, the European Space Agency (ESA) undertook the development of a European Radar Observatory (Sentinel-1), a polar orbiting two-satellite constellation for the continuation and improvement of SAR operational services and applications. Satellite and payload are being built to provide routine, day-and-night, all-weather medium (typically 10 m) resolution observation capability. Ground infrastructure is provided for planning, mission control, data processing, dissemination and archiving. Free and open data access is provided. Data quality of the Sentinel-1 data products is shown along with uncertainty estimation of retrieved information products confirming specified performance and indicating application growth potential. The unique data availability performance of the Sentinel-1 routine operations makes the mission particularly suitable for emergency response support, marine surveillance, ice monitoring and interferometric applications such as detection of subsidence and landslides.
    No preview · Article · May 2012 · Remote Sensing of Environment
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    ABSTRACT: The forthcoming two-satellite GMES Sentinel-1 constellation is expected to render systematic surface soil moisture retrieval at 1 km resolution using C-band SAR data possible for the first time from space. Owing to the constellation?s foreseen coverage over the Sentinel-1 Land Masses acquisition region?global approximately every six days, nearly daily over Europe and Canada depending on latitude?in the high spatial and radiometric resolution Interferometric Wide Swath (IW) mode, the Sentinel-1 mission shows high potential for global monitoring of surface soil moisture by means of fully automatic retrieval techniques. This paper presents the potential for providing such a service systematically over Land Masses and in near real time using a change detection approach, concluding that such a service is?subject to the mission operating as foreseen?expected to be technically feasible. The work presented in this paper was carried out as a feasibility study within the framework of the ESA-funded GMES Sentinel-1 Soil Moisture Algorithm Development (S1-SMAD) project.
    No preview · Article · Apr 2012 · IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
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    ABSTRACT: The Sentinel-1 satellite carries on board a C-band Synthetic Aperture Radar built from 560 active radiating waveguide arrays. The 280 horizontally polarised waveguide arrays and the 280 vertically polarised waveguide arrays are arranged as dual-polarised pairs in sufficient proximity to allow for grating lobe free electronic steering of the S-1 SAR antenna in the elevation plane. Each waveguide array is connected to a transmit-receive module (TRM) feeding or receiving signals via their common antenna port. The SAR instrument has an internal RF Characterisation mode exploiting the phase shifting capabilities of the TRMs, that allows monitoring of the individual excitations of each waveguide array in both Tx and Rx. The present paper reports on a novel Pulse Coded Calibration (PCC) scheme, that whilst maintaining some salient features of the Hadamard based PCC, also allows to optimise the antenna active return losses. A low active return loss is beneficial to minimise the RF stress of the TRM output circuitry and improves the accuracy of the RF Characterisation itself.
    No preview · Conference Paper · Jan 2012
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    ABSTRACT: This paper describes and assesses the quality of the algorithm, “Soil MOisture retrieval from multi-temporal SAR data” (SMOSAR), developed in view of the forthcoming European Space Agency (ESA) Sentinel-1 (S-1) mission. SMOSAR retrieves soil moisture (mv) products at high spatial resolution (i.e. less than 1km) from dense time series of either single (i.e. HH or VV) or dual polarized (i.e. HH+HV or VV+VH) S-1 data. The assessment of the algorithm performance is based on time series of ENVISAT/ASAR data collected over the DEMMIN site (Germany) in 2006 and over the Matera site (Italy) in 2003 and 2005 and RADARSAT-2 data acquired over the Flevoland site (The Netherlands) in 2009. Results indicate that mv can be retrieved with an accuracy of 5% at HH polarization, whereas at VV polarization more investigations are required to provide reliable figure for the retrievable accuracy.
    Full-text · Conference Paper · Jan 2012
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    ABSTRACT: In the framework of the EU/ESA co-funded Global Monitoring for Environment and Security (GMES) program, ESA is undertaking the development of the Sentinel-1 (S1) mission comprising a constellation of two satellites (A and B units) each carrying an imaging C-band SAR instrument. The objective of the S-1 mission is to acquire systematically and provide routinely data and information products for GMES and national services.
    No preview · Conference Paper · Jan 2012
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    ABSTRACT: The ESA Sentinels constitute the first series of operational satellites responding to the Earth Observation needs of the EU-ESA Global Monitoring for Environment and Security (GMES) programme. The GMES space component relies on existing and planned space assets as well as on new complementary developments by ESA. In contrast to SAR systems already existing in C-band like ASAR/ENVISAT or RADARSAT-2, high demands on the radiometric accuracy are made for Sentinel-1. This paper provides an overview of the main features of GMES Sentinel-1 System, a C-band Synthetic Aperture Radar Observatory for Earth Observation. The main system requirements are presented as drivers for the design of system, satellite and operations. The major design challenges as well as the most critical development aspects are outlined, mainly focusing on the Space Segment components.
    No preview · Conference Paper · Jan 2012
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    ABSTRACT: The ESA Sentinels constitute the first series of operational satellites responding to the Earth Observation needs of the EU-ESA Global Monitoring for Environment and Security programme. The GMES space component relies on existing and planned space assets as well as on new complementary developments by ESA. In particular, as part of the GMES space component, ESA is currently undertaking the development of 3 Sentinels mission families. Each Sentinel is based on a constellation of 2 satellites in the same orbital plane. This configuration allows to fulfil the revisit and coverage requirements and to provide a robust and affordable operational service. The launch of the 2nd satellite is scheduled 18 months after the launch of the 1st spacecraft of the constellation. The lifetime of the individual satellite is specified as 7 years, with consumables allowing mission extension up to 12 years. The lifecycle of the space segment is planned to be in the order of 15-20 years. The strategy for Sentinel procurement and replacement over this period is being elaborated, but will likely result in a need for 4-5 satellites of each type if the desired robustness for the service that GMES will provide is to be achieved. This paper will describe the operational and observational capabilities of the Sentinel-1 mission based on the user requirements, including potential emergency requests. An example of a pre-defined mission timeline for each and every cycle will be given.
    Preview · Article · Oct 2011 · Proceedings of SPIE - The International Society for Optical Engineering
  • [Show abstract] [Hide abstract]
    ABSTRACT: The ESA Sentinels constitute the first series of operational satellites responding to the Earth Observation needs of the EU-ESA Global Monitoring for Environment and Security programme. The GMES space component relies on existing and planned space assets as well as on new complementary developments by ESA. In particular, as part of the GMES space component, ESA is currently undertaking the development of 3 Sentinels mission families. Each Sentinel is based on a constellation of 2 satellites in the same orbital plane. This configuration allows to fulfil the revisit and coverage requirements and to provide a robust and affordable operational service. The launch of the 2nd satellite is scheduled 18 months after the launch of the 1st spacecraft of the constellation. The lifetime of the individual satellite is specified as 7 years, with consumables allowing mission extension up to 12 years. The lifecycle of the space segment is planned to be in the order of 15–20 years. The strategy for Sentinel procurement and replacement over this period is being elaborated, but will likely result in a need for 4-5 satellites of each type if the desired robustness for the service that GMES will provide is to be achieved. This paper will describe the operational and observational capabilities of the Sentinel-1 mission based on the user requirements, including potential emergency requests. An example of a pre-defined mission timeline for each and every cycle will be given.
    No preview · Article · Jan 2011
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    ABSTRACT: The EU-ESA Global Monitoring for Environment and Security (GMES) program calls for a number of different Satellites called Sentinels to be launched within the next 6 years. The first among these are the two Sentinel-1 polar orbiting sun-synchronous satellites which each carries onboard a C-band Synthetic Aperture Radar (C-SAR).
    Full-text · Article · Jan 2011
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    ABSTRACT: The letter introduces a novel quantizer suited for medium to high-resolution synthetic aperture radar (SAR) systems, like the forthcoming SENTINEL-1 SAR. The Flexible Dynamic Block Adaptive Quantization (FDBAQ) extends the concept of the Block Adaptive Quantization (BAQ), used in spaceborne SAR since the Magellan mission, by adaptively tuning the quantizer rate according to the local signal-to-noise-ratio (SNR). A design is presented aiming to optimize the average bit-rate, while constraining the minimum SNR. FDBAQ optimized performance is then evaluated using backscatter maps derived from ENVIronment SATellite (ENVISAT) data.
    Full-text · Article · Nov 2010 · IEEE Geoscience and Remote Sensing Letters
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    ABSTRACT: The ESA Sentinels constitute the first series of operational satellites responding to the Earth Observation needs of the EU-ESA Global Monitoring for Environment and Security (GMES) programme. The GMES space component relies on existing and planned space assets as well as on new complementary developments by ESA. This describes the Sentinel-1 mission, as imaging synthetic aperture radar (SAR) satellite constellation at C-band. It provides an overview of mission requirements, its applications and the technical concepts for the system.
    Full-text · Article · Sep 2010 · IEEE Aerospace and Electronic Systems Magazine
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    ABSTRACT: Sentinel-1 mission is designed to be a source of continuous and reliable collection of C-band SAR imagery. As part of the complete family of GMES Sentinels, Sentinel-1 guarantees continuity of C-band SAR data and products availability to scientific and institutional users who exploit satellite radar imagery since ERS 1 operations. Drivers for EO satellite missions operations are typically fast reaction and response times but also, in the case of Sentinel-1, complete Earth surface coverage within every orbit repeat cycle (12 days). Sentinel-1 mission capabilities and the defined operational scenario currently selected by the ESA Mission and System Manager will be presented in this paper.
    No preview · Conference Paper · Jul 2010
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    ABSTRACT: The paper reports about the comparison of the Sentinel-1 Prototype TOPS Processor with the Experimental TerraSAR-X TOPS processor. The comparison is based on simulated raw data generated from TerraSAR-X and Sentinel-1 parameter scenarios. Fundamental impulse response parameters were investigated in point target scenarios. Scenarios with point targets on top a noise floor allowed for comparison of burst images by means of a cross-interferogram. The comparison shows good accordance between the processing results from both processors.
    Full-text · Conference Paper · Jul 2010