A5086482137- Synthetic Aperture Radar (SAR) Applications and Techniques
- Soil Moisture and Remote Sensing
- Advanced SAR Imaging Techniques
- Precipitation Measurement and Analysis
- Cryospheric studies and observations
- Landslides and related hazards
- Antenna Design and Analysis
- Ocean Waves and Remote Sensing
- Microwave and Dielectric Measurement Techniques
- Microwave Engineering and Waveguides
- Geophysics and Gravity Measurements
- Electromagnetic Compatibility and Measurements
- Antenna Design and Optimization
- Underwater Acoustics Research
- Geophysical Methods and Applications
- Soil Geostatistics and Mapping
- Microwave Imaging and Scattering Analysis
- Advanced Antenna and Metasurface Technologies
- Radar Systems and Signal Processing
- RFID technology advancements
- Power Line Communications and Noise
- Mechanical and Optical Resonators
- Advanced MEMS and NEMS Technologies
- Advanced Fiber Optic Sensors
- Energy Harvesting in Wireless Networks
Universitat Politècnica de Catalunya
2015-2025
Shrinking mechanical resonators to submicrometer dimensions (approximately 100 nm) has tremendously improved capabilities in sensing applications. In this Letter, we go further size reduction using a 1 nm diameter carbon nanotube as resonator for mass sensing. The performances, which are tested by measuring the of evaporated chromium atoms, exceptional. responsivity is measured be 11 Hz x yg(-1) and resolution 25 zg at room temperature (1 yg = 10(-24) g 10(-21) g). By cooling down 5 K...
Bending-mode vibrations of carbon nanotube resonator devices were mechanically detected in air at atmospheric pressure by means a novel scanning force microscopy method. The fundamental and higher order bending eigenmodes imaged up to 3.1GHz with sub-nanometer resolution vibration amplitude. resonance frequency the eigenmode shape multi-wall nanotubes are consistent elastic beam theory for doubly clamped beam. For single-wall nanotubes, however, frequencies significantly shifted, which is...
In this paper, a new model-based technique for the compensation of severe height-dependent atmospheric artifacts, using ground-based synthetic aperture radar (SAR) data over mountainous regions, is proposed. The method presented represents an extension already existing techniques, but now taking into account effect steep topography in phase screen process. addition, adapted to work with polarimetric SAR data, showing, that case, noticeable improvement validated environment El Forn de...
Airborne synthetic aperture radar (SAR) sensors have been commonly used during the last decades to monitor different phenomena in medium-scale areas of observation, such as object detection and characterization or topographic mapping. The use unmanned aerial vehicles (UAVs) is a cost-effective solution that offers higher operational flexibility than airborne systems these types scenarios. Universitat Politècnica de Catalunya has developed first fully polarimetric SAR system at X-band...
Soil Moisture and Ocean Salinity (SMOS) is an Earth Explorer Opportunity Mission from the European Space Agency with a launch date in 2007. Its goal to produce global maps of soil moisture ocean salinity variables for climatic studies using new dual-polarization L-band (1400-1427 MHz) radiometer Microwave Imaging Radiometer by Aperture Synthesis (MIRAS). SMOS will have multiangular observation capability can be optionally operated full-polarimetric mode. At this frequency sensitivity...
This letter discusses the implementation of SABRINA, Synthetic Aperture radar Bistatic Receiver for Interferometric Applications. The ground resolution a fixed-receiver bistatic system is studied, showing that it comparable to monostatic system. Due short distance from target receiver, large sensitivity obtained. noncooperative nature forces conservative data-acquisition strategy based on continuously sampling scattered signal during temporal window around predicted satellite overpass time....
In this letter, a coherence-based technique for atmospheric artifact removal in ground-based (GB) zero-baseline synthetic aperture radar (SAR) acquisitions is proposed. For purpose, polarimetric measurements acquired using the GB-SAR sensor developed at Universitat Politecnica de Catalunya are employed. The heterogeneous environment of Collserola Park outskirts Barcelona, Spain, was selected as test area. Data sets were X-band during one week June 2005. effects atmosphere variations between...
Reflectometry using Global Navigation Satellite Systems signals (GNSSR) has been the focus of many studies during past few years for a number applications over different scenarios as land, ocean or snow and ice surfaces. In decade, its potential increased yearly, with improved receivers signal processors, from generic GNSS whose were recorded in magnetic tapes to instruments that measure full Delay Doppler Maps (the power distribution reflected 2‐D space delay offsets shifts) real time. At...
The interference pattern technique (IPT) consists of the coherent addition direct and reflected global navigation satellite systems (GNSS) signals in receiving antenna. detected power oscillates (fading), amplitude these oscillations is very sensitive to soil reflection coefficient at specular point. Therefore, variations can be mapped, thus dielectric constant variations, from which moisture retrieved. This work extends use IPT vertical polarization (V-Pol) horizontal (H-Pol). Moreover,...
The Remote Sensing Laboratory of the Universitat Politecnica de Catalunya carried out a one-year measuring campaign in village Sallent, northeastern Spain, using polarimetric ground-based synthetic aperture radar (SAR) sensor. objective was to study subsidence phenomenon induced by salt mining activity conducted this area up middle last century. Zero-Baseline SAR (PolSAR) data were gathered at X-band nine different days, from June 2006 March 2007. In letter, problem extracting information...
Prior to the application of any persistent scatterer interferometry (PSI) technique for monitoring terrain displacement phenomena, an adequate pixel selection must be carried out in order prevent inclusion noisy pixels processing. The rationale is detect so-called scatterers, which are characterized by preserving their phase quality along multi-temporal set synthetic aperture radar (SAR) images available. Two criteria mainly available estimation pixels’ quality, i.e., coherence stability and...
UAV (unmanned Aerial Vehicle) platforms represent a challenging opportunity for the deployment of number remote sensors. These vehicles are cost-effective option in front manned aerial (planes and helicopters), easy to deploy due short runways needed, they allow users meet critical requirements spatial temporal resolutions imposed by instruments. L-band radiometers an interesting obtaining soil moisture maps over local areas with relatively high resolution precision agriculture, coastal...
Global navigation satellite system reflectometry has already shown its potential to perform retrievals of a number geophysical parameters, including soil moisture, vegetation height, etc. This letter focuses on the study snow-covered soils using interference pattern technique (IPT) with Soil Moisture Interference-pattern GNSS Observations at L-band (SMIGOL) reflectometer, ground-based instrument. Snow effects are analyzed, and an algorithm been developed for this type surfaces. From November...
This paper describes a pair of compact CW/FM airborne SAR systems for small UAV-based operation (wingspan 3.5 m) low-cost testing innovative concepts. Two different instruments, using the C and X bands, have been developed in context ARBRES project, each them achieving payload weight below 5 Kg volume 13.5 dm3 (sensor controller). Every system has dual receiving channel which allows interferometric or polarimetric modes. Planar printed array antennas are used both sensors easy integration...
Ground-based synthetic aperture radar (SAR) (GB-SAR) sensors represent an effective solution for the monitoring of ground displacement episodes. Initially, most GB-SAR were based on vector network analyzers (VNA). This type solution, characterized by a slow scanning time comparable to decorrelation troposphere medium, compromised in many cases quality final products application persistent scatterer interferomerty (PSI) techniques. The development use stepped linear frequency modulated...
In this paper, a study of polarimetric optimization techniques in the frame differential synthetic aperture radar (SAR) interferometry (DInSAR) is considered. Historically, DInSAR have been limited to single-polarimetric case, mainly due unavailability fully data. Lately, launch satellites with capabilities, such as Advanced Land Observing Satellite (ALOS), RADARSAT-2, or TerraSAR-X, allowed merging and interferometric improve pixels' phase quality and, thus, density reliability final...
Revisiting time constitutes a key constraint for continuous monitoring activities based on space- and airborne synthetic aperture radar (SAR) acquisitions. Conversely, the employment of terrestrial platforms overcomes this limitation makes it possible to perform time-continuous observations small space-scale phenomena. New research lines SAR dealing with backscattering evolution different types scenarios become hence through analysis ground-based (gbSAR) data collections. The Remote Sensing...
Soil moisture (SM) is a key parameter in the climate studies at global scale and very important applications such as precision agriculture local scale. The Global Navigation Satellite Systems Interference Pattern Technique (IPT) has proven to be useful technique for determination of SM, based on observations vertical polarization (V-Pol) due Brewster angle. IPT can applied both V-Pol horizontal (H-Pol) same time, observing angle only V-Pol. This letter presents measurement tracking phase...
Urban subsidence and landslides are among the greatest hazards for people infrastructure safety they require an especial attention to reduce their associated risks. In this framework, ground-based synthetic aperture radar (SAR) interferometry (GB-InSAR) represents a cost-effective solution precise monitoring of displacements. This work presents application GB-InSAR techniques, particularly with RiskSAR sensor its processing chain developed by Remote Sensing Laboratory (RSLab) Universitat...
Patient monitoring of vital signals such as breathing rhythm and heartbeat rate can be done remotely by the use a radar system. This approach is advantageous since it does not require any contact with patient. Obviously, contactless results in more comfortable situation for patient, occasions, almost mandatory case heavy burned or newborn patients. Moreover, additional information movement patterns are also available. A 120 GHz frequency modulated continuous wave described special focus on...
Continuous terrain fast changes monitoring is difficult to implement via airborne/satellite SAR systems, mainly due the lack of flexibility and low revisiting times. Other approaches based on small simple ground-based easy deploy wherever are needed, must be considered. Transportability, cost, ruggedized structure main constrains, but required resolution performances have preserved. An experimental, short medium range, ground-based, with optional polarimetric capability, Synthetic Aperture...
The knowledge of the seawater dielectric properties is very important in areas remote sensing. models mainly used today seems not to be enough accurate for actual applications. A new model has been derived from measurements at L Band.
GNSS-R techniques are currently being studied to remotely sense a number of geophysical parameters over different types surfaces [1-6]. The Interference Pattern Technique (IPT) is based on the measurement interference pattern GPS direct and reflected signals, after reflecting surface, as satellites move. This paper extends previous studies [7-11], in which water level was monitored [7] land areas were observed retrieving soil moisture, topography vegetation height for kinds crops (wheat,...