204 research outputs found

    Deception jamming against anti-ship missiles which use doppler beam sharpening modes

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    Missile seekers are becoming increasingly more capable of using Doppler Beam Sharpening (DBS) modes as part of the homing cycle, which requires new countermeasures against this mode. One type of countermeasure, is to create false targets within the seeker DBS image. This thesis presents two implementation methods to insert false targets into DBS images. Both methods are used to create false targets at a precise location within a seeker DBS image, but are implemented in different ways. The first method proposes repeat jamming with a time-varying delay, whilst the second proposes a fixed delay and adding a specific Doppler shift to received waveforms. The effects of tracking errors on the position of the false target are analysed, both analytically and with simulations and used to assess the practical implementation of the jamming scheme. An experimental DBS system was built to test the effectiveness of the jamming scheme against a platform moving in steps and assess errors caused by incorrectly estimating the seeker trajectory. The overall result of the thesis is that using the derived jamming methods, false targets can be created at specific locations in the DBS image of the victim radar, providing the trajectory of the victim radar is known

    Optimised soft-core processor architecture for noise jamming

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    M.Ing. (Electrical & Electronic Engineering)Abstract: Noise jamming is a traditional electronic counter measure (ECM) that existed since the establishment of electronic warfare (EW). Traditional noise jamming techniques have been shown to be failing when interacting with intelligent Radar systems such as pulse Doppler radar. Hence there is a need to introduce new noise jamming techniques with digital architecture that will provide improved performance against smart pulse Doppler radar. The work is undertaken to investigate the feasibility of digitizing noise jamming. It focuses on analog-to-digital conversion optimization towards noise jamming architecture, as a result digitization will allow for an opportunity for adaptation of intelligent processing that previously didn’t exist. In this dissertation, certain contributions to the field of noise jamming were made by introducing state of the art odd/even order sampling architecture by proving four case studies. Case study 1 experimentally investigates sample frequency behaviour. Case study 2 uses simulation to investigate step-size and dynamic range behaviour. Case study 3 uses FPGA implementation and SNR to investigate quantization error behaviour. Case study 3 also uses SNR to investigate superiority of proposed odd/even order sampling. Lastly case study 4 uses field measurements, FPGA implementation and SNR to investigate practical implementation of digitized noise jamming. The main contribution is concerned with an architecture that digitizes, reduces sample frequency, optimizes digital resource utilization while reducing noise jamming signal-to-noise ratio. The approach evaluates and empirically compares three sampling techniques from lecture Mod-Δ, Mod-Δ (Gaussian) and Mod-Δ (Sinusoidal) with proposed novel odd/even order sampling. Sampling techniques are evaluated in terms of quantization error, mean square error and signal-to-noise ratio. It was found that the proposed novel odd/even order sampling achieved most case SNR performance of 6 dB in comparison to 18 dB for Mod-Δ. Sampling frequency findings indicated that the proposed novel odd/even order sampling had achieved sampling frequency of 2 kHz in comparison to 8 kHz from traditional 1st order sigma-delta. Dynamic range findings indicated that the proposed odd/even order sampling achieved a dynamic range of 1.088 volts/ms in comparison to 1.185 volts/ms from traditional 1st order sigma-delta. Findings have indicated that the proposed odd/even order sampling has superior SNR and sampling frequency..

    Coffee Can Radar: Detection and Jamming

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    This project models the operation of an interception-resistant automotive radar and demonstrates its susceptibility to jamming. The initial hardware design was based on open courseware from MIT Lincoln Laboratory. Prior to the construction of the radar, expected results were recorded using MATLAB and LTspice simulations. The interference signals were designed in MATLAB and transmitted using a software-defined radio. Final testing was completed using a spectrum analyzer and software designed to plot the time-lapsed location of a detected object

    Control Theory in Engineering

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    The subject matter of this book ranges from new control design methods to control theory applications in electrical and mechanical engineering and computers. The book covers certain aspects of control theory, including new methodologies, techniques, and applications. It promotes control theory in practical applications of these engineering domains and shows the way to disseminate researchers’ contributions in the field. This project presents applications that improve the properties and performance of control systems in analysis and design using a higher technical level of scientific attainment. The authors have included worked examples and case studies resulting from their research in the field. Readers will benefit from new solutions and answers to questions related to the emerging realm of control theory in engineering applications and its implementation

    Implementation and Analysis of Spectral Subtraction and Signal Separation in Deterministic Wide-Band Anti-Jamming Scenarios

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    With the increasing volume of wireless traffic that military operations require, the likelihood of transmissions interfering with each other is steadily growing to the point that new techniques need to be employed. Furthermore, to combat remotely operated improvised explosive devices, many ground convoys transmit high-power broadband jamming signals, which block both hostile as well as friendly communications. These wide-band jamming fields pose a serious technical challenge to existing anti-jamming solutions that are currently employed by the Navy and Marine Corps. This thesis examines the feasibility of removing such deterministic jammers from the spectral environment, enabling friendly communications. Anti-jamming solutions in self-jamming environments are rarely considered in the literature, principally due to the non-traditional nature of such jamming techniques. As a result, a combination of approaches are examined which include: Antenna Subset Selection, Spectral Subtraction, and Source Separation. These are combined to reduce environmental interference for reliable transmissions. Specific operational conditions are considered and evaluated, primarily to define the limitations and utility of such a system. A final prototype was constructed using a collection of USRP software defined radios, providing solid conclusions of the overall system performance

    2011 Annual Report of the Graduate School of Engineering and Management, Air Force Institute of Technology

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    The Graduate School\u27s Annual Report highlights research focus areas, new academic programs, faculty accomplishments and news, and provides top-level sponsor-funded research data and information
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