2007 ieee international symposium on electromagnetic compatibility

30EMC <strong>2007</strong> ADVANCE PROGRAMWaveform diversity in multistatic radar systems can enhance distributedradar system performance. Dynamically changing the electromagneticemanations of radar and communications systems, however,poses an electromagnetic compatibility (EMC) challenge. Dataare provided illustrating how waveform diversity improves multistaticradar system performance. An approach for maintaining EMC ina dynamically changing environment is also provided.Detection/Imaging of Buried Objects: Using Spatial/AngularDiversity with Distributed/Embedded Sub-Surface Sensorsfor Reduced Mutual Coupling and Suppressed EMEmissionsJohn Norgard, U. S. Air Force Research Lab/SNRT; Kevin Magde, U. S.Air Force Research Lab/Sensors Directorate; Michael Wicks, U. S. Air ForceResearch Lab/Sensors Directorate; Andrew Drozd, ANDRO ComputationalSolutions, LLC; and Randall Musselman, U. S. Air Force AcademyThe proliferation of strategic subsurface sanctuaries has increased theneed for enhanced remote sensing techniques providing for the accuratedetection and identification of deeply buried objects. A new RFTomographic Technique is proposed in this concept paper for developingRF CAT Scans of buried objects using spectral, spatial/angular,and polarization diversity. This imaging technique uses an embeddedring of subsurface radiators, delivered by earth-penetrating, nonexplosive,electronic “e-bombs”, as the source of strong undergroundradiated transmissions and uses distributed surface-contact sensors tocollect the tomographic data for relay to a circling UAV and transmissionto a remote control site (using layered sensing). Threedimensionalimaging algorithms are being developed to detect,image, and characterize deeply buried targets. Distributed transmittersand receivers significantly increase unwanted mutual couplingand EM emissions that interfere with signal reception. However, byembedding the transmitters underground, reduced mutual couplingand EM emissions (and improved signal-to-noise ratios) can beachieved. Simple surface SAR experiments over deep mine shaftshave been performed to validate the 3D processing algorithms using2D surface SAR sensor data. WIPL-D models have also been used tosimulate the embedded and distributed sensors and to verify the significantenhancement in the received signal-to-noise ratio obtainedby burying the radiating ring under the surface sensors.Electromagentic Diversity and EMI Implications for MultipleCo-Sited Radars and Targeting ApplicationsAndrew Drozd, ANDRO Computational Solutions, LLC; IrinaKasperovich, ANDRO Computational Solutions, LLC; Ruixin Niu,Syracuse University; and Pramod Varshney, Syracuse UniversityReal-time fusion of data collected from a variety of co-located radarsthat acquire information in a cooperative manner from multiple perspectivesand/or different frequencies, is being shown to provide amore accurate and effective way of tracking complex targets in amulti-target scenario. This is more advantageous than employing asingle radar or a group of radars operating independently. This paperdescribes a cooperative multi-sensor approach in which multipleradars operate together in a non-interference limited manner. Athree-fold approach is presented: (i) applying multiobjective jointoptimization algorithms to set limits on the operational parametersof the radars to preclude electromagnetic interference; (ii) measuringand processing radar returns in a shared manner for target featureextraction based on electromagnetic diversity principles in conjunctionwith target scattering cross sections; and (iii) employing featureaidedtrack/fusion algorithms to detect, discriminate, and follow realtargets from clutter noise. The results of computer simulations areprovided that demonstrate the advantages of this approach.The True Meaning of Electromagnetic Diversity SeenThrough the First Principles of Fundamental PhysicsTapan K. Sarkar, Department of Electrical Engineering and ComputerScience, Syracuse UniversityThe word Diversity in the dictionary implies variety in form. Andthe basic concept derived from these principles is that if one has multiplecopies of the same system, presumably one would have a betterchance of achieving the desired goals. The fundamental problemwith this simplistic way of reasoning is that one needs to understandthe physical environment where such an experiment needs to be carriedout and how one should interpret the final result. The currentstate of the art applies some statistical framework to the physicalscene to explain the added advantage of diversity. To appreciate thetrue physical significance of diversity we have to go back to the roots!We need to understand first, what the statistical framework impliesand secondly, how it relates to the problem at hand.Distributed and Layered Sensing: Relevant EMC IssuesMichael Wicks; and William Moore, — U. S. Air Force ResearchLab/Sensors DirectorateOne can easily envision future military operations and emergingcivilian requirements (e.g. intelligent unmanned vehicles for urbanwarfare, and intelligent manufacturing plants) that will be both complexand stressing and will demand innovative sensors and sensorconfigurations. The goal of our research into Distributed and LayeredSensing is to develop a cost effective and extendable approach for providingsurveillance for a variety of applications in dynamically changingmilitary and civilian environments. Within Distributed andLayered sensing, we foresee a new sensor archetype. In this paradigm,sensors and algorithms will be autonomously altered depending onthe environment. Radars will use the same returns to perform detectionand discrimination, to adjust the platform flight path, andchange mission priorities. The sensors will dynamically and automaticallychange waveform parameters to accomplish these goals.Disparate sensors will communicate and share data and instructionsin real-time. Intelligent sensor systems will operate within andbetween sensor platforms such that the integration of multiple sensordata provides information needed to achieve dynamic goals andavoid electromagnetic fratricide. Intelligent sensor platforms workingin partnership will increase information flow, minimize ambiguities,and dynamically change multiple sensors’ operations basedupon a changing environment. Concomitant with the current emphasison more flexible defense structures, Distributed and Layered sensingwill allow the appropriate incremental application of remotesensing assets by matching resources to the situation at hand.Effect of In-Band Intermodulation Interference on Direct-Sequence Spread Spectrum (DSSS) CommunicationSystems for Electromagnetically Diverse ApplicationsIlteris Demirkiran, Embry-Riddle Aeronautical University; Donald Weiner,Syracuse University; and Andrew Drozd, ANDRO ComputationalSolutions, LLCThe goal of this paper is to analyze the effect of nonlinearities on theperformance of direct-sequence spread spectrum systems in the contextof electromagnetically diverse applications. Inter-modulationproducts due to nonlinear amplification are analyzed and the effect ofnonlinearities is illustrated by means of a computer simulation result.For the performance measure, bit-error rate (BER) is considered toassess the effect of in-band intermodulation interference. The findingsof this study will be of benefit to the waveform diversity community.This community is concerned with assessing the effects of©<strong>2007</strong> IEEE www.emc<strong>2007</strong>.org