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권호별목차 / 소장처보기

H : 소장처정보

T : 목차정보

Advances in radio science 26건

  1. [해외논문]   Concept and design of a UAS-based platform for measurements of RF signal-in-space  

    Schrader, Thorsten , Bredemeyer, Jochen , Mihalachi, Marius , Rohde, Jan , Kleine-Ostmann, Thomas
    Advances in radio science v.14 ,pp. 1 - 9 , 2016 , 1684-9965 ,

    초록

    Abstract. Field strength or signal-in-space (SIS) measurements have been performed by using manned helicopters, aircrafts or from ground level using extendable masts. With the availability of unmanned aerial systems (UAS) such as multicopters a new versatile platform for SIS measurements is deployable. Larger types show up to eight individually driven electric motors and controllers (therefore called octocopter). They provide the ability to fly along predefined traces, to hover at waypoints and to initiate other actions when those have been reached. They provide self-levelling and stabilisation and moreover, they may gear at a point of interest regardless of their actual position, e.g. during their flight around a tower. Their payload mainly depends on the platform size and allows integration of complex measurement equipment. Upgrading their navigation capabilities including state-of-the-art global navigation satellite system (GNSS) and ground station transmitter (real-time kinematic - RTK) enables precise localisation of the UAS. For operation in electromagnetic harsh environments a shielding can be considered and integrated into the concept. This paper describes concept and design of an octocopter and its instrumentation, along with applications in recent projects, in which we measure and validate terrestrial navigation systems applied in air traffic and the weather forecast services. Among those are instrumentation landing systems (ILS), VHF omnidirectional radio ranges (VOR), airport traffic and weather radars as well as military surveillance radars, and UHF wind profilers. Especially to investigate the possible interaction of VORs and radars with single wind turbines (WT) or wind power plants has become a major request of economy, military and politics. Here, UAS can be deployed to deliver measurement data investigating this interaction. Once developed and setup to a certain extent, UAS are easy and cost-efficient to operate. Nonetheless, due to their compact size, UAS will have rather low interaction with the electromagnetic field to be measured compared to the operation of manned helicopters.

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    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  2. [해외논문]   Results of an intercomparison for free space antenna factor measurements within the German Calibration Service (DKD)  

    Kleine-Ostmann, Thomas , Huncke, Frank , Schwarzbeck, Dieter , Martetschlä , ger, Otto , Gaßner, Jü , rgen , Guserle, Andreas , Rö , mer, Christian , Hufnagel, Thomas , Lehmann, Mario , Karsten, Uwe , Schrader, Thorsten
    Advances in radio science v.14 ,pp. 11 - 16 , 2016 , 1684-9965 ,

    초록

    Abstract. In this paper we discuss the results of an intercomparison for free space antenna factor measurements performed within the German Calibration Service (DKD). Three different types of antennas covering the frequency range from 30 MHz to 26.5 GHz have been calibrated in five different laboratories using different methods and calibration sites to obtain the free space antenna factor. The results agree well within the uncertainties specified by the laboratories suggesting that different approaches and different measurement sites to obtain the free space antenna factor are well compatible.

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    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  3. [해외논문]   Uncertainty contribution of a wind turbine to the electric field of a DVOR antenna as a function of wind direction and rotor position  

    Sandmann, Sergei , Garbe, Heyno
    Advances in radio science v.14 ,pp. 17 - 24 , 2016 , 1684-9965 ,

    초록

    Abstract. The presence of a wind turbine (WT) has the potential to distort electromagnetic fields emitted by terrestrial radio navigation aids. In this paper especially the field distortion of a Doppler Very High Frequency Omnidirectional Radio Range (DVOR) surveillance navigation system is investigated as a function of wind direction and rotor position. Therefor, the field distribution of a DVOR is simulated in the surrounding of a WT for 104 combinations of the angles of wind direction and rotor position. Furthermore, these calculations are executed for two different rotor diameters and 10 steps of distance between DVOR and WT in the range of 10 km. Based on the calculated data a method to estimate the maximum field distortion is developed. It is shown that the presented method allows to approximate the worst case field distortion with the results of two general simulation setups. Eliminating the need of simulating all possible geometric constellations of the WT this method hereby offers the benefit of significantly reduced simulation effort.

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    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  4. [해외논문]   Design and analysis of ultra-wideband antennas for transient field excitations  

    Kotzev, Miroslav , Kreitlow, Matthias , Gronwald, Frank
    Advances in radio science v.14 ,pp. 25 - 29 , 2016 , 1684-9965 ,

    초록

    Abstract. This work addresses the design of two ultra-wideband antennas for the application of transient field measurements that are characterized by frequency spectra that typically range from a few MHz to several GHz. The motivation for their design is the excitation of high power transient pulses, such as double exponential or damped sinusoidal pulses, within highly resonant metallic enclosures. The antenna design is based on two independent numerical full-wave solvers and it is aimed to achieve a low return loss over a wide range of frequencies together with a high pulse fidelity. It turns out that antennas of the conical and discone type do achieve satisfactory broadband characteristics while limitations towards low frequencies persist. Also the concept of fidelity factor turns out as advantageous to determine whether the proposed antennas allow transmitting certain broadband pulse forms.

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    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  5. [해외논문]   Virtual sensor models for real-time applications  

    Hirsenkorn, Nils , Hanke, Timo , Rauch, Andreas , Dehlink, Bernhard , Rasshofer, Ralph , Biebl, Erwin
    Advances in radio science v.14 ,pp. 31 - 37 , 2016 , 1684-9965 ,

    초록

    Abstract. Increased complexity and severity of future driver assistance systems demand extensive testing and validation. As supplement to road tests, driving simulations offer various benefits. For driver assistance functions the perception of the sensors is crucial. Therefore, sensors also have to be modeled. In this contribution, a statistical data-driven sensor-model, is described. The state-space based method is capable of modeling various types behavior. In this contribution, the modeling of the position estimation of an automotive radar system, including autocorrelations, is presented. For rendering real-time capability, an efficient implementation is presented.

    원문보기

    원문보기
    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  6. [해외논문]   Extended Kalman Doppler tracking and model determination for multi-sensor short-range radar  

    Mittermaier, Thomas J. , Siart, Uwe , Eibert, Thomas F. , Bonerz, Stefan
    Advances in radio science v.14 ,pp. 39 - 46 , 2016 , 1684-9965 ,

    초록

    Abstract. A tracking solution for collision avoidance in industrial machine tools based on short-range millimeter-wave radar Doppler observations is presented. At the core of the tracking algorithm there is an Extended Kalman Filter (EKF) that provides dynamic estimation and localization in real-time. The underlying sensor platform consists of several homodyne continuous wave (CW) radar modules. Based on In-phase-Quadrature (IQ) processing and down-conversion, they provide only Doppler shift information about the observed target. Localization with Doppler shift estimates is a nonlinear problem that needs to be linearized before the linear KF can be applied. The accuracy of state estimation depends highly on the introduced linearization errors, the initialization and the models that represent the true physics as well as the stochastic properties. The important issue of filter consistency is addressed and an initialization procedure based on data fitting and maximum likelihood estimation is suggested. Models for both, measurement and process noise are developed. Tracking results from typical three-dimensional courses of movement at short distances in front of a multi-sensor radar platform are presented.

    원문보기

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    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  7. [해외논문]   Implementation of a digital evaluation platform to analyze bifurcation based nonlinear amplifiers  

    Feldkord, Sven , Reit, Marco , Mathis, Wolfgang
    Advances in radio science v.14 ,pp. 47 - 50 , 2016 , 1684-9965 ,

    초록

    Abstract. Recently, nonlinear amplifiers based on the supercritical Andronov-Hopf bifurcation have become a focus of attention, especially in the modeling of the mammalian hearing organ. In general, to gain deeper insights in the input-output behavior, the analysis of bifurcation based amplifiers requires a flexible framework to exchange equations and adjust certain parameters. A DSP implementation is presented which is capable to analyze various amplifier systems. Amplifiers based on the Andronov-Hopf and Neimark-Sacker bifurcations are implemented and compared exemplarily. It is shown that the Neimark-Sacker system remarkably outperforms the Andronov-Hopf amplifier regarding the CPU usage. Nevertheless, both show a similar input-output behavior over a wide parameter range. Combined with an USB-based control interface connected to a PC, the digital framework provides a powerful instrument to analyze bifurcation based amplifiers.

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    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  8. [해외논문]   Adapting the range of validity for the Carleman linearization  

    Weber, Harry , Mathis, Wolfgang
    Advances in radio science v.14 ,pp. 51 - 54 , 2016 , 1684-9965 ,

    초록

    Abstract. In this contribution, the limitations of the Carleman linearization approach are presented and discussed. The Carleman linearization transforms an ordinary nonlinear differential equation into an infinite system of linear differential equations. In order to transform the nonlinear differential equation, orthogonal polynomials which represent solutions of a Sturm-Liouville problem are used as basis. The determination of the time derivate of this basis yields an infinite dimensional linear system that depends on the considered nonlinear differential equation. The infinite linear system has the same properties as the nonlinear differential equation such as limit cycles or chaotic behavior. In general, the infinite dimensional linear system cannot be solved. Therefore, the infinite dimensional linear system has to be approximated by a finite dimensional linear system. Due to limitation of dimension the solution of the finite dimensional linear system does not represent the global behavior of the nonlinear differential equation. In fact, the accuracy of the approximation depends on the considered nonlinear system and the initial value. The idea of this contribution is to adapt the range of validity for the Carleman linearization in order to increase the accuracy of the approximation for different ranges of initial values. Instead of truncating the infinite dimensional system after a certain order a Taylor series approach is used to approximate the behavior of the nonlinear differential equation about different equilibrium points. Thus, the adapted finite linear system describes the local behavior of the solution of the nonlinear differential equation.

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    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  9. [해외논문]   Advanced binary search pattern for impedance spectra classification for determining the state of charge of a lithium iron phosphate cell using a support vector machine  

    Jansen, Patrick , Vollnhals, Michael , Renner, Daniel , Vergossen, David , John, Werner , Gö , tze, Jü , rgen
    Advances in radio science v.14 ,pp. 55 - 62 , 2016 , 1684-9965 ,

    초록

    Abstract. Further improvements on the novel method for state of charge (SOC) determination of lithium iron phosphate (LFP) cells based on the impedance spectra classification are presented. A Support Vector Machine (SVM) is applied to impedance spectra of a LFP cell, with each impedance spectrum representing a distinct SOC for a predefined temperature. As a SVM is a binary classifier, only the distinction between two SOC can be computed in one iteration of the algorithm. Therefore a search pattern is necessary. A balanced tree search was implemented with good results. In order to further improvements of the SVM method, this paper discusses two new search pattern, namely a linear search and an imbalanced tree search, the later one based on an initial educated guess. All three search pattern were compared under various aspects like accuracy, efficiency, tolerance of disturbances and temperature dependancy. The imbalanced search tree shows to be the most efficient search pattern if the initial guess is within less than ±5 % SOC of the original SOC in both directions and exhibits the best tolerance for high disturbances. Linear search improves the rate of exact classifications for almost every temperature. It also improves the robustness against high disturbances and can even detect a certain number of false classifications which makes this search pattern unique. The downside is a much lower efficiency as all impedance spectra have to be evaluated while the tree search pattern only evaluate those on the tree path.

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    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

    이미지

    Fig. 1 이미지
  10. [해외논문]   Data preprocessing for a vehicle-based localization system used in road traffic applications  

    Patelczyk, Timo , Lö , ffler, Andreas , Biebl, Erwin
    Advances in radio science v.14 ,pp. 63 - 69 , 2016 , 1684-9965 ,

    초록

    Abstract. This paper presents a fixed-point implementation of the preprocessing using a field programmable gate array (FPGA), which is required for a multipath joint angle and delay estimation (JADE) used in road traffic applications. This paper lays the foundation for many model-based parameter estimation methods. Here, a simulation of a vehicle-based localization system application for protecting vulnerable road users, which were equipped with appropriate transponders, is considered. For such safety critical applications, the robustness and real-time capability of the localization is particularly important. Additionally, a motivation to use a fixed-point implementation for the data preprocessing is a limited computing power of the head unit of a vehicle. This study aims to process the raw data provided by the localization system used in this paper. The data preprocessing applied includes a wideband calibration of the physical localization system, separation of relevant information from the received sampled signal, and preparation of the incoming data via further processing. Further, a channel matrix estimation was implemented to complete the data preprocessing, which contains information on channel parameters, e.g., the positions of the objects to be located. In the presented case of a vehicle-based localization system application we assume an urban environment, in which multipath propagation occurs. Since most methods for localization are based on uncorrelated signals, this fact must be addressed. Hence, a decorrelation of incoming data stream in terms of a further localization is required. This decorrelation was accomplished by considering several snapshots in different time slots. As a final aspect of the use of fixed-point arithmetic, quantization errors are considered. In addition, the resources and runtime of the presented implementation are discussed; these factors are strongly linked to a practical implementation.

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    무료다운로드 유료다운로드

    회원님의 원문열람 권한에 따라 열람이 불가능 할 수 있으며 권한이 없는 경우 해당 사이트의 정책에 따라 회원가입 및 유료구매가 필요할 수 있습니다.이동하는 사이트에서의 모든 정보이용은 NDSL과 무관합니다.

    NDSL에서는 해당 원문을 복사서비스하고 있습니다. 아래의 원문복사신청 또는 장바구니담기를 통하여 원문복사서비스 이용이 가능합니다.

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