13 research outputs found

    High Speed Dim Air Target Detection Using Airborne Radar under Clutter and Jamming Effects

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    The challenging potential problems associated with using airborne radar in detection of high Speed Maneuvering Dim Target (HSMDT) are the highly noise, jamming and clutter effects. The problem is not only how to remove clutter and jamming as well as the range migration and Doppler ambiguity estimation problems due to high relative speed between the targets and airborne radar. Some of the recently published works ignored the range migration problems, while the others ignored the Doppler ambiguity estimation. In this paper a new hybrid technique using Optimum Space Time Adaptive Processing (OSTAP), Second Order Keystone Transform (SOKT), and the Improved Fractional Radon Transform (IFrRT) was proposed. The OSTAP was applied as anti-jamming and clutter rejection method, the SOKT corrects the range curvature and part of the range walk, then the IFrRT estimates the target’ radial acceleration and corrects the residual range walk. The simulation demonstrates the validity and effectiveness of the proposed technique, and its advantages over the previous researches by comparing its probability of detection with the traditional methods. The new approach increases the probability of detection, and also overcomes the limitation of Doppler frequency ambiguity

    Bistatic synthetic aperture radar imaging using Fournier methods

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    Space-Variant Post-Filtering for Wavefront Curvature Correction in Polar-Formatted Spotlight-Mode SAR Imagery

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    Detección Espectral Indirecta para un Radar Pulsante Wavelet

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    In this article we propose a simple distance estimation based on a pulsed radar system. The method consists of sending periodic signals formed from an orthogonal wavelet family and measuring the echo’s delay produced by the target in a domain different than the temporal one. The results of the simulations show an acceptable precision in the determination of the distance, avoiding the complex methods of synchronization, filtering and decision, used in traditional pulsed radars.En este artículo proponemos una estimación de distancia simple soportada en un sistema de radar de pulso. El método consiste en enviar señales periódicas formadas a partir de una familia wavelet ortogonal y la medida del atraso del eco producido por el albo e un dominio diferente al temporal. Los resultados de las simulaciones muestran una precisión aceptable en la determinación de la distancia, evitando los métodos complejos de sincronización, filtrado y decisión, utilizados en radares de pulso tradicionale

    Detección Espectral Indirecta para un Radar Pulsante Wavelet

    Get PDF
    In this article we propose a simple distance estimation based on a pulsed radar system. The method consists of sending periodic signals formed from an orthogonal wavelet family and measuring the echo’s delay produced by the target in a domain different than the temporal one. The results of the simulations show an acceptable precision in the determination of the distance, avoiding the complex methods of synchronization, filtering and decision, used in traditional pulsed radars.En este artículo proponemos una estimación de distancia simple soportada en un sistema de radar de pulso. El método consiste en enviar señales periódicas formadas a partir de una familia wavelet ortogonal y la medida del atraso del eco producido por el albo e un dominio diferente al temporal. Los resultados de las simulaciones muestran una precisión aceptable en la determinación de la distancia, evitando los métodos complejos de sincronización, filtrado y decisión, utilizados en radares de pulso tradicionale

    A moving target velocity estimation method based on the MC-MASA SAR mode

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    Imaging position shift based on the multiple azimuth squint angles (MASA) mode is effective for target azimuth velocity estimation, whereas accuracy is low when target range velocity is high. In this paper, the estimation problem for both target azimuth and range velocities is considered based on the multi-channels MASA (MC-MASA) mode. Firstly, the acquisition geometry of MC-MASA mode and Doppler characteristics of a moving target are analyzed in detail, especially in squint mode. Then, for better moving target estimation, the stationary background clutter is removed using the displacement phase center antenna (DPCA) technique, and the failure in range velocity estimation with sequential SAR images is also discussed. Furthermore, a modified along-track interferometry (ATI) is proposed to preliminarily reconstruct the azimuth-and-range velocity map based on the MC-MASA mode. Since the velocity estimation accuracy is dependent on squint angle and signal-to-clutter ratio (SCR), the circumstances are divided into three cases with different iteration estimation strategies, which could expand the scene application scope of velocity estimation and achieve a high estimation accuracy along both azimuth and range directions. Finally, the performance of the proposed method is demonstrated by experimental results
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