Patrick Millot

A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building

A study of an ultrawideband frequency-modulated continuous-wave radar with an extended frequency sweep from 0.5 to 8 GHz is presented. It has been applied to through-the-wall human detection. This work presents the modeling of wall attenuation followed by real measurements. The radar system is presented, and trials of human being tracking are shown. This radar will enable large stand-off distance capabilities and dasiadasiain-depthpsilapsila building detection.

ELECTROMAGNETIC IMAGING METHOD BASED ON TIME REVERSAL PROCESSING APPLIED TO THROUGH-THE-WALL TARGET LOCALIZATION

A time reversal method is studied and adapted to throughthe-wall detection and localization of moving targets. Tests are realised on experimental data in a synthetic aperture radar configuration. The efficiency of the method to extract a moving target from a cluttered environment is proved on experimental data.

Array-Based Ultrawideband through-Wall Radar: Prediction and Assessment of Real Radar Abilities

This paper deals with a new through-the-wall (TTW) radar demonstrator for the detection and the localisation of people in a room (in a noncooperative way) with the radar situated outside but in the vicinity of the first wall. After modelling the propagation through various walls and quantifying the backscattering by the human body, an analysis of the technical considerations which aims at defining the radar design is presented. Finally, an ultrawideband (UWB) frequency modulated continuous wave (FMCW) radar is proposed, designed, and implemented. Some representative trials show that this radar is able to localise and track moving people behind a wall in real time.

Array-based UWB FMCW Through-The-Wall radar

We present the development and preliminary results of an ultra-wideband Frequency Modulated Continuous Wave (FMCW) Through-The-Wall (TTW) radar prototype built at ONERA in Toulouse, France. The radar operates between 1 and 4 GHz. The radar has been successfully tested through a plasterboard wall and trials with a cinder block wall are ongoing.

Experimental through-the-wall detection in cluttered environment using time reversal processing

The detection and localization of persons through obstacles is becoming a great stake in both civil and military fields. One of the most important applications is certainly sensing through walls which can be very useful in safety, peace-keeping and law enforcement operations. Radar systems are likely to provide an adequate answer to this kind of problem and various processing methods are nowadays studied and considered to reach the final solution. In this paper, we focus on ultra-wideband radar techniques applied to human sensing. In particular, we assume that we have an antenna array on reception. Many signal processing methods can be considered for target localization. We choose to focus on an emerging method in electromagnetic detection field, especially in a cluttered environment: time-reversal [1] adapted here to through-the-wall localization. In this work time reversal processing is applied to experimental data to demonstrate the localization of dielectric objects behind a 10 cm thick brick wall.

Experimental study of near-surface radar imaging of buried objects with adaptive focused synthetic aperture processing

This paper deals with the application of stepped frequency radar to subsurface imaging of buried targets with a final aim of object imaging and identification. The applications are mainly mines or UXO detection but also buried pipes. The depths considered here are a few cm to 15 cm under the surface (from the top of the object). It is necessary to use a UWB radar in order to separate the soil interface from the top of the object. A versatile system has been built that can be brought outdoor. It is used to find the best parameters for a future optimal radar. Special antennas have been realized that cover the 500 MHz to 8 GHz frequency range. The antenna pair (T/R) moves at a given height over the soil surface along a rail. Radar returns are then processed on a PC in order to deliver in a few seconds a 2D vertical profile of the soil. A special algorithm for near field synthetic focusing aperture has been developed for this task. It takes into account the wave propagation in the soil. Tomographic images are presented for different objects in different soils (.5 to 5 GHz and 2 to 8 GHz bandwidths) that show the quality of the results delivered by this improved technique. Conclusion are drawn on the potentialities and the limitations of the method and future perspectives like 3D imaging.

An Original Method for the Measurement of the Radiated Susceptibility of an Electronic System Using Induced Electromagnetic Nonlinear Effects

The objective of this paper is to propose an improved approach based on a novel nonintrusive method for easily assessing the high frequency CW EM radiated susceptibility of an electronic system by characterizing its nonlinear electromagnetic effects. For this purpose, we have developed a specific harmonic frequency detection system coupled with a mode stirrer reverberating chamber. We describe the principles of the method and study a generic device board which is representative of a real electronic system. We evaluate the EM susceptibility of a micro controller in full functional mode and the data exchanges with two types of external 8 Mb SRAM memories. We observe the EM radiated susceptibility of this device by a functional EMC analysis method; then we measure the harmonic frequency content and make a correlation with the EM susceptibility results. We obtain significant differences between the two memory devices, as a consequence of their different managements of internal voltage over stress. We are well aware that this method is currently not validated in industrial environments EMC. In this paper, we only want to show that the appearance of the highest harmonic level occurs only when DUT has the highest functional failure.