Through wall indoor surveillance and monitoring is an emerging area of research and developments in many real-life applications, including security and search and rescue. In this context, it is important to deploy remote sensors able to glean information about the presence of people in indoor areas. Radar devices based on the exploitation of electromagnetic signals represent an attractive sensing modality. When operating at frequencies from hundreds of MHz to few GHz, they are capable to penetrate common construction materials enabling the detection of people in inaccessible environments. Two different types of surveillance radars are considered in this paper. The first one exploits the synthetic aperture concept with the aim to detect, locate, and track multiple subjects in the scene. The second one illuminates the scene from a fixed position and exploits the Doppler effect. Despite the limited information available with respect to aperture radars, Doppler radars allow the detection of moving targets behind walls and inside enclosed structures. This work presents a brief overview of recent developments in the field of radar data processing for indoor monitoring together with their assessment by means of numerical and experimental tests.
The specially calculated and prepared antiradar surfaces on special ships is very good for detecting them by the
microwave radiometers. It is interesting to evaluate the possibility of using a passive millimeter wave (PMMW)
radiometric discriminator for the remote controlling and finding such objects at real distances and also for
The paper summarizes results of step-frequency radars application in medicine. Remote and non-contact control of physiological parameters with modern bioradars provides a wide range of possibilities for non-contact remote monitoring of a human psycho-emotional state and physiological condition. The paper provides information about technical characteristics of bioradars designed at Bauman Moscow State Technical University and experiments using them. Results of verification experiment showed that bioradars of BioRASCAN type may be used for simultaneous remote measurements of breathing and heart rate parameters. In addition, bioradar assisted experiments for detecting of different sleep disorders are described. Their results proved that method of bioradiolocation allows correct estimation of obstructive sleep apnea severity compared to the polysomnography method, which satisfies standard medical recommendations.
High-resolution through-the-wall radar imaging (TWRI) systems can provide a high degree of situational awareness in
urban sensing applications. However, such systems generate huge amounts of data, owing to the use of wideband signals
and large arrays to achieve high resolutions in range and crossrange. This makes both data acquisition and processing
challenging. In this paper, we present fast data acquisition and processing schemes for TWRI. We use compressive
sensing and novel concepts of microwave tomography to establish a reduced-redundancy spatial and frequency
measurement configuration, which provides clear advantages in terms of measurement time and algorithm complexity.
Performance validation of the proposed strategy is provided using laboratory experiments.
Experimental validation of a tomographic technique for radar imaging of 3-D scenes behind walls is presented. The
imaging technique is based on a linear inverse scattering algorithm combined with a 2-D sliced approach, which ensures
fast data processing and quick investigation of very large spatial regions. Further, we investigate the possibility of
achieving 3-D reconstructions using a limited set of data with the objective of reduction in data acquisition time, while
maintaining a reasonable image quality. Performance of the limited data schemes is evaluated using experimental data
collected in a semi-controlled environment.
This contribution deals with the effect of the background removal procedure on GPR data for an inverse scattering
algorithm funded on the Born Approximation in the simple case of a scalar two-dimensional geometry. The effect is
examined with regard to both the problem of the extraction of scattered field data from the total field data and to the
performances of the reconstruction approach. As it will be shown, the background removal amounts to a spatial filtering
of the available reconstruction and, depending on the kind of target looked for, it can be very useful but also quite useless
or even harmful.
The experimental validation of a numerical technique for temperature/strain sensing, based on frequency domain fiber-optic Brillouin measurements, is presented. In this technique both measurements and the signal processing are performed in the frequency domain. The algorithm is based on a harmonic expansion of the unknown profile, whose coefficients are determined by means of a multidimensional minimization. Preliminary results prove the validity of the proposed technique.
In this paper we apply a tomographic approach to the reconstruction of dielectric objects embedded in a layered medium, showing its reconstruction capability and robustness against noise. The problem is tackled with reference to a two-dimensional geometry and within the framework of the linear Distorted Born Approximation (DBA). Relying on the Singular Value Decomposition (SVD) of the operator describing the problem, the favorable effect of the increase in the band of adopted frequencies is also outlined. Numerical examples are provided to assess effectiveness robustness of the proposed approach against noise on data.
In the framework of ARCHEO, a national research project funded by the Italian Ministry for Universities and Scientific and Technological Research (M.U.R.S.T.), a new ground penetrating radar (GPR) has been developed by the Italian Consortium for Research on Advanced Remote Sensing Systems (CO.RI.S.T.A.). The system has been specially designed to meet archaeological requirements and it will be tested the two archaeological sites of Sinuessa and Cales, in the Southern Italy. An innovative feature of ARCHEO concerns the exploitation of that of a multiview multistatic measurement scheme (at several frequencies) rather than a more common multimonostatic (or multibistatic). In order to reconstruct buried objects starting from the measurement data collected with such an acquisition strategy, it is made use of an inverse scattering technique. With the real project ARCHEO in mind (in particular this scheme of measurement), this paper deals with a theoretical discussion on the features of the class of retrievable profiles by G.P.R. data, within the framework of a linear model for electromagnetic scattering in a two dimensional lossless half space. For a given range of frequencies exploitable, multiview multistatic measurements can be useful in G.P.R. prospecting because they can provide information on low spatial harmonic components of an unknown object not attainable from the multimonostatic scheme exploiting the same frequency range. In particular, we show that, for a given band of work frequencies, the class of the unknowns retrievable by a multiview multistatic multifrequency measurement configuration can be is not much different from that attainable within a multimonostatic configuration with the addition of multiview multistatic data taken at the lowest of the frequencies adopted.
The information content of radiated fields and the achievable resolution limits in the reconstruction of a bounded current distribution are dealt with. The analysis refers to the scalar and one dimensional case of a rectilinear and bounded electric current distribution when data are collected over a segment location in the Fresnel or near zone, orthogonal and centered with respect to the source. In the Fresnel zone, the investigation is carried out by means of the analytical Singular Value Decomposition (SVD) of the radiation operator providing the unknown-data mapping. This has been made possible thanks to the introduction of suitable weighted scalar products both in the unknown and data spaces. In the near zone, a numerical approach based on the SVD of the radiation operator has been followed. The effect of the geometrical parameters of the measurement configuration on depth resolving power is also discussed.