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  • 1.
    Lien, Kristian
    Swedish National Defence College.
    ”LIDAR, en sensorrevolusjon for Hæren?”2014Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    LIDAR is a type of sensor that has not yet been put into operation by the army's combat units. The technology's scope is broad, and for this thesis limited to a sensor role in a ground-to-ground scenario in combat units, where the sensor is used to build a commander's situational awareness (SA).

    In this thesis the results from both social scientific and scientific methods have been merged to measure the military utility of a sensor and its role for a military leader in contributing to his situational awareness and how this enables him to execute basic tactical principles. Data has been collected via literature studies, interviews and study visits to the Swedish Defence Research Agency (FOI). The results show the important role a sensor has as a direct contributor to a military leader’s situational awareness and his ability to execute basic tactical principles. Furthermore, the results clearly indicate where a LIDAR sensor can improve this role. It will do this because of its capability to detect well, classify and identify at long ranges, and its ability to penetrate natural and man-made obscurants and camouflage.

    The conclusions are that a LIDAR can be used by armoured combat units as a targeting sensor, and that the fielding of such a system will give a leader increased SA and a better basis for decisions. It is also clear that it cannot replace the systems in use today, but will be a complementary system that can be used under given circumstances.

  • 2.
    Persson, Björn
    et al.
    Swedish National Defence College, Department of Military Studies, Military-Technology Division.
    Norsell, Martin
    Swedish National Defence College, Department of Military Studies, Military-Technology Division.
    Conservative RCS models for simulationArticle in journal (Other academic)
  • 3.
    Persson, Björn
    et al.
    Swedish Defence University, Department of Military Studies, Military-Technology Division. KTH.
    Norsell, Martin
    Swedish Defence University, Department of Military Studies, Military-Technology Division.
    On Modeling RCS of Aircraft for Flight Simulation2014In: IEEE Antennas & Propagation Magazine, ISSN 1045-9243, E-ISSN 1558-4143, Vol. 56, no 4, 34-43 p.Article in journal (Refereed)
    Abstract [en]

    This paper investigates the implementation of the radar cross section (RCS) of aircraft in modeling and simulation (M&S). More specifically, it addresses the tradeoff between accuracy and computational cost introduced by spatial RCS fluctuations. High-resolution RCS matrices, generated using Physical Optics (PO), were used in an investigation of RCS matrix resolution, and an evaluation of different bilinear interpolation methods is presented. The spatial Fourier transform was used for resolution analysis. It was found that the smallest RCS interpolation error was obtained using splines. Furthermore, results showed that the distribution of the relative interpolation error in detection range was well approximated by a log-normal distribution.

  • 4.
    Persson, Björn
    et al.
    Department of Vehicle Engineering, Royal Institute of Technology, Stockholm, Sweden..
    Norsell, Martin
    Swedish Defence University, Department of Military Studies, Military-Technology Division.
    Reduction of RCS Samples Using the Cubed Sphere Sampling Scheme2016In: Progress In Electromagnetics Research M, ISSN 1937-8726, Vol. 48, 103-112 p.Article in journal (Refereed)
    Abstract [en]

    An alternative to the traditional method of sampling radar cross section data from measurements or electromagnetic code is presented and evaluated. The Cubed Sphere sampling scheme solves the problem of oversampling at high and low elevation angles and at equal equatorial resolution the scheme can reduce the number of samples required by approximately 25%. The analysis is made of an aircraft model with a monostatic radar cross section at C-band and a bistatic radar cross section at VHF-band, using Physical Optics and the Multilevel Fast Multipole Method, respectively. It was found that for the monostatic radar cross section, the Cubed Sphere sampling scheme required approximately 12% fewer samples compared to that required for traditional sampling while maintaining the same interpolation accuracy ever the entire domain. For the bistatic data, it was possible to reduce the number of samples by approximately 45% for high sampling resolutions. Using spline interpolation the number of samples required could be reduced even further. 

  • 5.
    Silfverskiöld, Stefan
    et al.
    Swedish National Defence College, Department of Military Studies, Military-Technology Division.
    Backstrom, M.
    Loren, J.
    Microwave field-to-wire coupling measurements in anechoic and reverberation chambers2002In: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, Vol. 44, no 1, 222-232 p.Article in journal (Refereed)
    Abstract [en]

    Knowledge of the differences in radiated susceptibility (RS) testing in anechoic (AC) and reverberation chambers (RC) is essential for analysis of the susceptibility of electronic systems to microwave radiation. We have studied microwave field-to-wire coupling for some basic wire geometries above a ground plane in ACs and RC. Results for receiving parameters such as the antenna receiving cross section sigma(w) and the effective antenna length of the wire, h(e), are presented. The ratio between the maximum and average values of sigma(w) may exceed 15 dB in the AC, the average being equal to sigma(w) measured in the RC. Large variations in sigma(w) show that the outcome of an RS test in an AC may depend strongly on the direction and polarization of the incident field. For a realistic RS test in ACs only a few angles of incidence can typically be afforded, implying a substantial risk for undertesting. Furthermore, a. measured in the RC follows a chi(2)-distribution with two degrees of freedom. The measurements in the AC do not follow the same distribution.

  • 6.
    Silfverskiöld, Stefan
    et al.
    Swedish National Defence College, Department of Military Studies, Military-Technology Division.
    Bäckström, Mats
    Totalförsvarets Forskningsinstitut, FOI.
    Lorén, Jörgen
    Totalförsvarets Forskningsinstitut, FOI.
    Microwave Field-to-Wire Coupling Measurements1998Conference paper (Refereed)
    Abstract [en]

    Knowledge of antenna receiving properties of wires and cables is essential in the analysis of susceptibility of electronic systems to microwave radiation. This paper presents measurements of receiving parameters for basic wire geometries. Directional properties of realized gain, receiving cross section and of effective antenna lenght for the wires are presented. The impact of measured directivity effects of the order of 15 dB on radiated susceptibility testing in anechoic and mode-stirred chambers is discussed.

  • 7.
    Silfverskiöld, Stefan
    et al.
    Swedish National Defence College, Department of Military Studies, Military-Technology Division.
    Bäckström, Mats
    Totalförsvarets forskningsinstitut, FOI.
    Lorén, Jörgen
    Totalförsvarets forskningsinstitut, FOI.
    Microwave Field-to-Wire Coupling Measurements in Anechoic and Reverberation Chambers2002In: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, Vol. 44, no 1, 222-232 p.Article in journal (Refereed)
    Abstract [en]

    Knowledge of the differences in radiated susceptibility (RS) testing in anechoic (AC) and reverberation chambers (RC) is essential for analysis of the susceptibility of electronic systems to microwave radiation. We have studied microwave field-to-wire coupling for some basic wire geometries above a ground plane in ACs and RC. Results for receiving parameters such as the antenna receiving cross section and the effective antenna length of the wire, he, are presented. The ratio between the maximum and average values of the antenna receiving cross section may exceed 15 dB in the AC, the average being equal to the antenna receiving cross section measured in the RC. Large variations in the antenna receiving cross section show that the outcome of an RS test in an AC may depend strongly on the direction and polarization of the incident field. For a realistic RS test in ACs only a few angles of incidence can typically be afforded, implying a substantial risk for undertesting. Furthermore, the antenna receiving cross section measured in the RC follows a Chi-square-distribution with two degrees of freedom. The measurements in the AC do not follow the same distribution.

  • 8.
    Silfverskiöld, Stefan
    et al.
    Swedish National Defence College, Department of Military Studies, Military-Technology Division.
    Thottappillil, Rajeev
    Uppsala Universitet, Institutionen för Högspänningsforskning.
    Ye, Ming
    Uppsala Universitet, Institutionen för Högspänningsforskning.
    Cooray, Vernon
    Uppsala Universitet, Institutionen för Högspänningsforskning.
    Scuka, Viktor
    Uppsala Universitet, Institutionen för Högspänningsforskning.
    Induced Voltages in a Low-Voltage Power Installation Network Due to Lightning Electronmagnetic Fields: An Experimental Study1999In: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, Vol. 41, no 3, 265-271 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents the experimental results on the induced common-mode (CM) voltages in a residential low-voltage power installation (LVPI) network exposed to electromagnetic fields from lightning. The objective of this investigation was to find out the severity of inducedvoltages in a low voltage network due to direct coupling of the lightning electromagnetic fields with the network in the absence of transient overvoltages coming through the distribution lines. Therefore, during the experiment the LVPI network was disconnected from the distribution network to exclude conducted transients in the measured signals entering through the mains. The induced CM voltages in a power outlet of the network were measured simultaneously with the vertical component of the electric field near the installation. The sequence of induced voltage events during the complete duration of one negative cloud-to-ground (CG) flash, one positive CG flash, and one cloud flash (CC), thought to be typical, is presented simultaneously with the electric field. It is shown that in addition to the return strokes in ground flashes, other discharge events taking place in the cloud; notably, the bipolar pulse trains associated with the initiation of both CG lightning and cloud lightning, are also important in determining the transient environment of electronic devices connected to a LVPI network. Flashes at a distance of about 25 km produced many induced-voltage pulses as large as 100 V, six such pulses in a time period of 0.4 ms in a negative CG flash, and 11 such pulses in a time period of 3 ms in a CC that immediately followed the ground flash.

  • 9.
    Sivertun, Åke
    Swedish National Defence College, Department of Military Studies, Military-Technology Division. MTA Försvarhögskolan.
    Critique systems for Geographic information and GIS2009In: Proceedings at 24th International Cartographic Conference ICC 2009 Santiago, Chile, Santiago, Chile, 2009Conference paper (Refereed)
  • 10.
    Sivertun, Åke
    2Department of Computer and Information Science (IDA), Linköping University, Sweden.
    Integration of remote sensed images and semantic based Descriptors for Hazards and risks management2008Conference paper (Refereed)
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