Using Polynomial Wigner-Ville Distribution for Velocity Estimation in Remote Toll Applications

International audienceThis letter presents the use of polynomial Wigner- Ville distribution (PWVD) for accurate velocity estimation as used in remote road traffic management applications. In such applica- tions based on inverse synthetic aperture radar, velocity estimation is central to obtain a suitable level of performance of the signal processing. Moreover, the precision of this velocity estimation is crucial in order to achieve the best detection and estimation of the gauge of the vehicles through the use of radar images. Hence, the PWVD is applied as an instantaneous frequency estimator used in this traffic surveillance application

Matching stereoscopic SAR images for radargrammetric applications

International audienceThe aim of this paper is to present our studies about extraction of 3D information from radar images. Several radargrammetric methods allow DEM (Digital Elevation Model) generation from SAR images and we take a special interest to stereoscopic method. The main idea is to match image stereo pairs, to create a disparity map from one image to the other and to compute elevation thanks to the incidences angle

SCATTERING MECHANISM ANALYSIS USING MULTI-ANGULAR POLARIMETRIC RADARSAT-2 DATASETS

International audienceThe objective of this study is to analyze scattering mecha- nisms using multi-incidence angle observations over agri- cultural fields. Radarsat-2 datasets acquired in the end of March / beginning of April with four different ranges of incidence angle are explored using polarimetric decom- position methodology. The results show that single scat- tering is always the dominant scattering mechanism over test sites, although single scattering occurs on bare sur- face is significantly stronger than that occurs in vegeta- tion canopy. As incidence angle increases, single scatter- ing decreases, and volumetric scattering increase as ex- pected. Therefore, lower incidence angle acquisition is appropriate to characterize soil moisture over bare sur- face due to the limited effect of roughness, while higher incidence angle is suitable for surface roughness iden- tification over bare surface and plant height description over vegetation canopy. Nevertheless, as the incidence angle increases towards 4

SOIL MOISTURE CHARACTERIZATION USING MULTI-ANGULAR POLARIMETRIC RADARSAT-2 DATASETS

International audienceThe use of multi-angular polarimetric datasets instead of the standard single-angular data is considered to be a solution to improve the effectiveness of bare soil char- acterization. However, the potential of polarimetric pa- rameters derived from the multi-angular SAR datasets was studied little, particularly for the C band polarimet- ric datasets. In this study, the sensitivity of polarimetric descriptors from single and multiple incidence angle acquisitions is investigated against in situ soil moisture and surface roughness. The behaviours of polarimetric descriptors are compared with the simulations using integral equation model (IEM). The results show that the variation of polarimetric descriptors in term of soil moisture as well as surface roughness is in accordance with the IEM simulations; even though the variation scale is different between the real data and simulation (The simulation is more sensitive than the real data). The polarimetric sensitivity found in this study provides additional evidences for the potential utilization of multi-angular polarimetric SAR datasets for bare sur- face characterization

A synthetic aperture interferometric radiometer test at X-band for potential improvements at W-band

International audienceThe broad topic of the presented paper consists in the research on novel methods in the field of microwave imaging, in particular the so-called passive microwave / millimeter-wave imaging, which is also referred to radiometric imaging. This study focuses on proximity range applications such as concealed objects detection, human body screening, etc. The aim is to design a low cost and compact fully electronic passive imaging system suitable for short-range 2D imaging applications, and study the necessary devices for the implementation of a complete demonstrator. In this study, a new approach based on the use of a switch sub-matrix strategy has been adapted into a complete antenna system at X band. The main objective of this prototype is to validate this approach experimentally. Image quality is examined by using the interferometric aperture synthesis technique and G-matrix calibration imaging algorithms. The spatial resolution is measured using the emission from noise source and compared with theory

A 2D Synthetic Aperture Radiometry Demonstrator by Switching Strategy at X band

International audienceThe broad topic of the presented paper consists in the research on novel methods in the field of microwave imaging, in particular the so-called passive microwave / millimeter-wave imaging, which is also referred to radiometric imaging. This study focuses on proximity range applications such as concealed objects detection, human body screening, etc. The aim is to design a low cost and compact fully electronic passive imaging system suitable for short-range 2D imaging applications, and study the necessary devices for the implementation of a complete demonstrator. In this study, a new approach based on the use of a switch sub-matrix strategy has been adapted into a complete antenna system at X band. The main objective of this prototype is to validate this approach experimentally. Image quality is examined by using the interferometric aperture synthesis technique and G-matrix calibration imaging algorithms. The spatial resolution is measured by using the emission from noise source and is compared with theory

A 2D Synthetic Aperture Radiometry Demonstrator by Switching Strategy at X band

International audienceThe broad topic of the presented paper consists in the research on novel methods in the field of microwave imaging, in particular the so-called passive microwave / millimeter-wave imaging, which is also referred to radiometric imaging. This study focuses on proximity range applications such as concealed objects detection, human body screening, etc. The aim is to design a low cost and compact fully electronic passive imaging system suitable for short-range 2D imaging applications, and study the necessary devices for the implementation of a complete demonstrator. In this study, a new approach based on the use of a switch sub-matrix strategy has been adapted into a complete antenna system at X band. The main objective of this prototype is to validate this approach experimentally. Image quality is examined by using the interferometric aperture synthesis technique and G-matrix calibration imaging algorithms. The spatial resolution is measured by using the emission from noise source and is compared with theory

Investigations on OFDM Signal for Range Ambiguity Suppression in SAR Configuration

International audienceThis paper presents an opportunity to cancel range ambiguities in synthetic aperture radar (SAR) configuration. One of the limitations of SAR systems is the range ambiguity phenomenon that appears with long delayed echoes. The reflected signal corresponding to one pulse is detected when the radar has already transmitted the next pulse. Thus, this signal is considered as an echo from the next pulse. This paper investigates the opportunity of coding the transmitted pulses using an orthogonal frequency-division multiplexing pulse. The results show that coded-OFDM signals outperform conventional chirp signal and make it possible to relax constraints placed upon the pulse repetition frequency

Investigating the Influence of Rotating Steel Platform in the RCS Measurement of Vehicles At 22-26 GHz for Automotive Radar Application

International audienceThis paper investigates the influence of rotating applications, such as ACC (Adaptive Cruise Control) or FCW steel platform in the RCS (Radar Cross Section) measurement of (Forward Collision Warning). vehicles at 22-26 GHz for automotive radar application. Across several measurement steps, we compare different RCS measurement results in order to eliminate the undesired RCS contribution caused mainly by the rotating steel platform. We demonstrate that when it is difficult or impossible to use microwave absorbers on the steel platform, an alternative scan (symmetry of vehicle) of target vehicle, the VUT should method can be applied. Finally, with the help of 2D radar image be positioned on a rotating steel platform. The RCS measurement configuration could be described as follows. As in a real road cruising situation, we carry out RCS measurements in outdoor conditions. Secondly, considering the weight of VUT, and the need of a continuous 180° azimuth post processing, we can also identify and separate the RCS contribution of each element (vehicle, steel platform, ground/multipath/clutter) in the hologram image, and therefore obtain the pure RCS distribution of the tested vehicle

Investigating the Influence of Rotating Steel Platform in the RCS Measurement of Vehicles At 22-26 GHz for Automotive Radar Application

International audienceThis paper investigates the influence of rotating applications, such as ACC (Adaptive Cruise Control) or FCW steel platform in the RCS (Radar Cross Section) measurement of (Forward Collision Warning). vehicles at 22-26 GHz for automotive radar application. Across several measurement steps, we compare different RCS measurement results in order to eliminate the undesired RCS contribution caused mainly by the rotating steel platform. We demonstrate that when it is difficult or impossible to use microwave absorbers on the steel platform, an alternative scan (symmetry of vehicle) of target vehicle, the VUT should method can be applied. Finally, with the help of 2D radar image be positioned on a rotating steel platform. The RCS measurement configuration could be described as follows. As in a real road cruising situation, we carry out RCS measurements in outdoor conditions. Secondly, considering the weight of VUT, and the need of a continuous 180° azimuth post processing, we can also identify and separate the RCS contribution of each element (vehicle, steel platform, ground/multipath/clutter) in the hologram image, and therefore obtain the pure RCS distribution of the tested vehicle