Research On Several Key Techniques Of Electromagnetic Situation Generation In Sea Battlefield

With the widespread use of electromagnetic technology and electronic equipment,electromagnetic environment (EME) of battlefield has become increasingly complex, andspectrum has become more and more important. Especially in the naval battlefield with a highlevel of information technology, EME has put forward higher requests to command andcontrol—that is, to a considerable degree, demands for comprehensive electromagneticsituation (EMS). As an important complement to conventional battlefield situation, EMSplays a key role in various battle domains, such as emitter data fusion, spectrum deployment,schema optimization in tactic-level, decision supporting in campaign-level, and so on.Therefore, electromagnetic situation generation (EMSG), consisting of environmentunderstanding, situational awareness, and situation representation, has become a critical factorin electromagnetic supremacy.According to the needs of EMS in naval Command&Control and spectrummanagement (SM), this thesis studies the architecture of EMSG, and proposes a frameworkfor EMSG in sea battlefield. Based on deeply research on several key techniques in EMSG,including situation representation, situation analysis, and situation assessment, we proposesome noval models and methods, and also present the theoretical analysis and the experimentresults. The main innovative achievements are as follows:(1) An electromagnetic situation generation framework (EMSGF) for sea battlefield isbuilt. Based on hierarchical processing principle in traditional situation models, the EMSGFconsists of four process domains—electromagnetic environment awareness, electromagneticenvironment constructing, electromagnetic situation understanding, and electromagneticsituation representation. In addition, we define the concepts and terms of EMS and its processdomains. Models for typical equipment and propagation loss, and an EM characterizationmethod are presented to construct the virtual electromagnetic environment. We also introducethe concepts, objectives, and technology of situation analysis and situation assessment, whichare the essential components of situation understanding. The proposed EMSGF shouldcontribute to the integrity and normalization of EMSG.(2) A time-adaptive visualization approach for EME situation representation is proposed.Expressing a specified electromagnetic area in the form of bitmap consisting of pixels, we cancreate the histogram of spectrum features. Then the change in frequency-domain of thespecified EM area can be measured by calculating the distance of feature vectors between histograms. Based on the measurement of variability of EME and parallel coordinates method,a time-adaptive visualization approach for multi-dimensional EME situation representation isrealized. We propose an Advanced Parallel Coordinates Method (APCM) to build avisualization framework for multi-dimensional EMS representation. It mainly includes threealgorithmic modules of a data fitting, a quantitative mapping, an adaptive time-slidingwindow. Respectively, the data fitting model mitigates the degree of line overlapping betweenthe correlated adjacent data dimensions by Bezier curve. The quantitative mapping model canmap the multi-dimensional information in different sizes and types into coordinate system.Based on them, the adaptive time-sliding window model can adjust time interval of situationrepresentation dynamically in order to make it adaptable to the change in an electromagneticenvironment. The experiments show that the APCM is an effective approach to displaymulti-dimensional EMS information quickly and precisely.(3) For large number of spectrum-depending nodes, this thesis proposes a modelingapproach for relation network of electromagnetic interference. In consideration of the largenumber of electronic equipment in naval fleet, we build a complex network model, in whichelectronic equipment are nodes and interference relation are edges. Two forms of the modelare presented—one with real-time analyze, the other with experiential statistic. The twomodels are named as A-EMIN and B-EMIN, respectively. A series of simulations and analysisof the two EMINs reveal some useful network characteristic that make sense to bothinterference analysis and spectrum management. The simulation result of cluster characteristicof B-EMIN verifies the rationality of a hierarchical SM strategy. In addition, we presentseveral EMIN metrics based on network features such as degree, density, mean distance,clustering coefficient, and so on. Explaining what these metrics mean in EMINs, we point tothe application potential of them in EMIN evaluation.(4) An electromagnetic situation assessment system for sea battlefield is set up. Takinginto account of all the factors considered in EMS, we propose a relatively comprehensiveindex system for EMS assessment. According to the structural feature of naval fleet, ahierarchical, quantitative assessment model for some indices is proposed, in which thesituation data is collected from equipment-level, and flows to fleet-level in a bottom-up way.Consequently, the measure of this index on fleet-level is generated with consideration overequipment weight and task weight. Applied to evaluating the index of EMI degree in fleet, themodel is proven to be effective. An FCM based situation assessment model is proposed inconsideration of the feature that most indices influence each other. We present the quantification method for adjacency matrix of FCM, and improve the threshold function andinference algorithm to make the model applicable to EMS assessment. Compared with theconventional EME assessment approaches, the FCM takes into consideration of variousfactors and the relations between them, produces more accurate results, and has a certainability of situation prediction.