Design and Applications of Multi-Frequency Holographic Subsurface Radar: Review and Case Histories

Holographic subsurface radar (HSR) is not currently in widespread usage. This is due to a historical perspective in the ground-penetrating radar (GPR) community that the high attenuation of electromagnetic waves in most media of interest and the inability to apply time-varying gain to the continuous-wave (CW) HSR signal preclude sufficient effective penetration depth. While it is true that the fundamental physics of HSR, with its use of a CW signal, does not allow amplification of later (i.e., deeper) arrivals in lossy media (as is possible with impulse subsurface radar (ISR)), HSR has distinct advantages. The most important of these is the ability to do shallow subsurface imaging with a resolution that is not possible with ISR. In addition, the design of an HSR system is simpler than for ISR due to the relatively low-tech transmitting and receiving antennae. This paper provides a review of the main principles of HSR through an optical analogy and describes possible algorithms for radar hologram reconstruction. We also present a review of the history of development of systems and applications of the RASCAN type, which is possibly the only commercially available holographic subsurface radar. Among the subsurface imaging and remote sensing applications considered are humanitarian demining, construction inspection, nondestructive testing of dielectric aerospace materials, surveys of historic architecture and artworks, paleontology, and security screening. Each application is illustrated with relevant data acquired in laboratory and/or field experiments

ДИСТАНЦИОННО-ПИЛОТИРУЕМЫЕ ЛЕТАТЕЛЬНЫЕ АППАРАТЫ И БЕЗОПАСНОСТЬ ПУТИ

The terrorist attacks attempts executed in Russia and abroad as well as probability of their repetition at high speed railways make it necessary to reinforce the measures of counteraction to those threats. The measures of control of the zone of tracks are engineered, including air monitoring and aerial photography, in order to ensure security of train traffic, to prevent possible acts of sabotage, immediate detection of explosive devices. The article is devoted to one of these measures, namely to remotely piloted aircrafts with optical sensors. The authors substantiate their advantages, demonstrate the results of the pilot researches, and offer comparison between airplane and helicopter type aircrafts, used for monitoring.Известные в стране и за рубежом факты  террористических актов и вероятность  их повторения на высокоскоростных  линиях железных дорог заставляют усиливать меры противодействия подобным угрозам. Для обеспечения безопасности движения поездов, предотвращения возможных диверсий, своевременного обнаружения взрывных устройств разрабатываются методы контроля в зоне рельсового полотна, включая воздушные наблюдения и аэрофотосъемку. Один из таких способов – применение дистанционно-пилотируемых летательных аппаратов с оптическими датчиками – предлагается в публикуемой статье. Даются обоснование их преимуществ, результаты  проведенных экспериментальных исследований, а также сравнения аппаратов вертолетного и самолетного типов, используемых для мониторинговой разведки

БЕСКОНТАКТНАЯ ДИАГНОСТИКА РЕЛЬСОВ: ЭФФЕКТ ПОЛЯРИЗАЦИИ ОТРАЖЕННОГО СВЕТА

Competition at the transportation market, increased velocity of the traffic, complication of operation conditions for rolling stock and infrastructure cause new anthropogenic risks, reduce traffic safety. Railways need new methods to prevent risks, particularly to monitor the railway tracks. The joint researches conducted by Moscow State University of Railway Engineering, Bauman Moscow State Technical University and JSC Russian Railways have resulted in development of the tools of contactless diagnostics and troubleshooting of the rails using reflected light polarization effect.Острая конкуренция на транспортном рынке, рост перевозочных скоростей, усложнение условий эксплуатации подвижного состава и инфраструктуры увеличивают техногенные риски, снижают безопасность движения. В ответ возникает естественная потребность в более строгих профилактических мерах. Железным дорогам, в частности, нужен надежный мониторинг стальных путей. Совместный научный поиск в этом направлении специалистов МИИТ, МГТУ им. Баумана и ОАО «РЖД» помог совершенствованию средств бесконтактной диагностики рельсов

Simulation of recording the microwave holograms of complex objects by the near range radars

Radar is an object-detection technology that uses radio waves to determine the presence, range, altitude, direction, or speed of objects. In the recent time, there is an increasingly arising interest to the near range microwave imaging that allows detection of the shape and, in some cases, the inner structure of the investigated objects.For design engineering and efficiency evaluation of the cutting-edge radars as well as for testing the developed recovery algorithms a set of microwave holograms of various objects obtained under different conditions is needed. Microwave holograms cannot be obtained only on the basis of the experimental researches related to the measurements of electromagnetic scattering by the real objects since such experiments are time consuming and quite expensive. Therefore, to simulate electromagnetic scattering processes via objects examination is quite a challenge.This investigation goal is to develop a computer simulation method to record the microwave holograms of complex objects by the near range radars.To specify the shape of the investigated objects, Autodesk 3ds Max (3D computer graphics program for making 3D animations, models, and images) is used. At a second stage the surface of the created object is described by a set of triangular facets. While calculating the reflected field, a final representation of the object as a set of point reflectors is used. Thus, the model of single scattering, is used without taking into consideration re-reflection and cross-influence of reflectors.Methods are also described to form the focused images of the microwave holograms that allow us to obtain a function describing object reflectivity, by which in most cases an object shape can be easily recognized.A comparison of computer-simulated holograms with experimental data proves the model adequacy.The model can be used to find a dependence of the plane resolution on used frequency, step of scanning, and distance to the object and a dependence of the range resolution on the used frequency band. It can be also used for estimation of the aperture size and unambiguous range and to answer the other questions arising in designing the near range radars.</p

Remote Control Mine Detection System with

ABSTRACT In this paper we describe a method of minefield reconnaissance with the use of the multi-frequency groundpenetrating radar (GPR) combined with a metal detector. This method allows the mine images in the soil to be obtained in the band of the mine detector sensors. An experimental installation with remote control and scanning sensors has been designed and built. A mine detector of this kind can be used in peacekeeping and humanitarian operations