A. G. Yarovoy

UWB array-based radar imaging using modified Kirchhoff migration

This paper presents a new modification of Kirchhoff migration algorithm for ultra-wideband (UWB) array-based radar imaging. The developed algorithm is evolved from traditional Kirchhoff migration which is based on the classical integral theorem of Helmholtz and Kirchhoff. The new algorithm is designed for array-based radar imaging with arbitrary multiple input multiple output (MIMO) configuration. The developed algorithm is compared with conventional diffraction stack migration using both synthetic data from numerical simulation and measurement data from landmine detection. The results have shown promising improvements in the aspects of beamwidth, side-lobe rejection ratio and the ability to reconstruct shapes of distributed targets.

Planar Dual-Band Wide-Scan Phased Array in X-Band

The design of a planar dual-band wide-scan phased array is presented. The array uses novel dual-band comb-slot-loaded patch elements supporting two separate bands with a frequency ratio of 1.4:1. The antenna maintains consistent radiation patterns and incorporates a feeding configuration providing good bandwidths in both bands. The design has been experimentally validated with an X-band planar 9 × 9 array. The array supports wide-angle scanning up to a maximum of 60 ° and 50 ° at the low and high frequency bands respectively.

Comparison of UWB technologies for human being detection with radar

UWB radar for detection and positioning of human beings in complex environment can be developed based on different technologies such as video impulse, quasi-random noise, stepped-frequency continuous wave and frequency-modulated continuous wave. These technologies are compared on the basis of meeting functional requirements to such a radar. Relative advantages and disadvantages of these technologies for such an application as human being detection and positioning are pointed out. Recommendations for selection of an optimal technology are given.

UWB Channel Measurements and Results for Office and Industrial Environments

This paper presents the results of ultra wide band (UWB) channel measurements carried out at the campus of Delft University of Technology. The measurements were conducted in an indoor office and industrial environment using a time domain setup which allows measurements from 3.1 to 10.6 GHz. Results on large scale path-loss exponent, shadowing, small scale fading and rms delay spread (RDS) for indoor office and industrial area propagation are presented

EUROPCOM: Emergency Ultrawideband RadiO for Positioning and COMmunications

This paper provides an overview of the EUROPCOM demonstrator, a UWB based positioning and communication system for emergency personnel, which allows efficient management and coordination of rescue operations in disaster zones, particularly inside of buildings. The system architecture is reviewed, key aspects of the PHY, MAC, NET, and positioning (POS) sub-systems are highlighted. Ranging and positioning performance results are presented. The main challenge addressed by the system design is a self-calibrating location aware network of nodes in an ad-hoc scenario, which is able to operate under non-line-of-sight conditions. The EUROPCOM demonstrator has been developed under the Sixth Framework Program of the European Commission.

Improved Bow-Tie Antenna for Pulse Radiation and Its Implementation in a GPR Survey

In our previous works we developed an improved UWB bow-tie antenna for high-resolution GPR applications. The antenna has been designed to detect small shallow-buried objects for which it should be able to transmit short pulses with very small late-time ringing. It has been shown theoretically that in comparison with conventional bow-tie or dipole antennas, this antenna radiates significantly stronger pulses in its broadside direction with very small late-time ringing. In this paper, experimentally we compare the antenna with a resistively-loaded planar dipole which is commonly used for GPR. It has been found that the antenna exhibits superior characteristics in terms of significantly larger amplitude of the transmitted pulses and much smaller late-time ringing. Furthermore, the antenna has been implemented in a commercial GPR system and tested in real GPR surveys. In this paper we demonstrate that the implementation of this antenna results in clear B-scan images which allow one to easily observe the detail of the shallow subsurface.

Assessment of Electromagnetic Requirements for UWB Through-Wall Radar

This paper investigates electromagnetic requirements for ultra-wideband (UWB) through-wall radar. It includes the evaluation of propagation loss, dynamic range and radar resolution for typical through-wall scenarios. The evaluation results in analysis and comparison of different transmission schemes.

Suppression of noise and narrowband interference in UWB indoor channel measurements

In this paper, the impact of the noise due to undersampling of noncoherent narrowband interference in time domain UWB channel measurements is investigated. Different measurements were carried out within the building for LOS and NLOS situations. The obtained results show that energy of external narrowband interference (especially at frequencies below 3.1 GHz) is spread over the whole measured bandwidth (1-12 GHz) as a quasi-white noise. This spreading is caused by the stroboscopic sampling receiver used in the measurement setup. The level of this additional noise is relatively high and its suppression is required for long-distance measurements. Suppression of the narrowband interference by an analogue bandpass filter directly after the receive antenna substantially decreases the noise floor and results in a large improvement of the signal-to-noise ratio.

UWB MIMO Antenna Array Topology Design Using PSO for Through Dress Near-field Imaging

In this paper two novel MIMO UWB antenna arrays have been proposed for through dress imaging radar application. The advantage of using MIMO array is that the number of elements can be reduced and the element spacing can be sparser than that of SIMO array, while the performance will be almost the same. Particle swarm optimization (PSO) method is used to determine the optimum antenna array topologies for different scenarios that can provide sufficient cross-range resolution and an acceptable mainlobe to side lobe level. The results demonstrated that by properly design the fitness function, we can trade off the cross-range resolution and mainlobe to sidelobe ratio and find proper array topologies for different scenarios.

Joint IRCTR/TNO-DS&S measurement campaign for AP-mine detection with VIR GPR

The results of the measurement campaign held during the autumn of 2004 in a sand pit located at the TNO-DS&S (formerly known as TNO Physics and Electronics Laboratory (FEL)) GPR test facility Waalsdorp in The Hague, The Netherlands, are presented. Some contamination of the sand in the pit with small scatterers (e.g. sea shells) comparable in size with smaller anti-personnel mines (APM) and roughness of the soil/air interface make the APM detection a non-trivial task.The performance of the energy-based and feature based data processing schemes and resulting images are compared and discussed. The performance of the detector relevant to the above mentioned data processing schemes are judged with receiver operating characteristics (ROC) curves built on the basis of the automated detector.