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In the paper the concept of a passive radar that uses several processing chains working with different setup parameters is considered. In the presented concept, the same signals are divided into blocks of different lengths, and processed simultaneously. In such way higher signal-to-noise ratios can be achieved for non-maneuvering targets by using longer integration time, whereas highly maneuvering...
Compressive sensing (CS) for radar signal processing is known to be capable of various applications. This signal processing technique shows excellent performance for detecting objects. However, the grid problem of CS is an obstacle to more precise performance. In this paper, we introduce two methods to overcome this grid problem and evaluate the performance of the methods. The first method is an up-sampled...
Orthogonal Frequency Division Multiplexing (OFDM) based waveform has been widely used as illuminator of opportunity in passive radar systems. Ambiguity function (AF) of OFDM is shown to be nearly perfect thumbtack shaped except for the undesirable high side lobes in the Doppler dimension. In this paper, we propose a novel filtered OFDM scheme to improve OFDM AF by utilizing Filtered Bank Multi-Carrier...
Frequency-Modulated Continuous-Wave Synthetic Aperture Radar (FMCW SAR) is a promising compact remote imaging sensor. A refocusing method of ground moving targets for FMCW SAR is derived considering the moving target range cell walk within a long coherent processing interval. To discriminate the target optimally, the concept of relative motion is utilized. By searching a relative factor, moving targets...
In this paper we analyze the shape reproduction errors of continuous spectrum of random Gaussian process (particularly, echo signals from meteorological formations in pulse Doppler weather radar) using various spectral estimation (SE) methods in “adaptive” situation when a priori unknown covariance matrix (CM) is replaced with its estimates of different kind. We also show the significant robustness...
The impact of Wind Turbine (WT) echo signals on diverse types of radars has been studied world-wide and with good success understanding the interference mechanisms in principal. However, there is a lack of practical approaches to calculate the acceptance for planned wind parks near radar stations. The officials commissioned with acceptability proving often refuse WT project request based on some simple...
Recent critical instances have demonstrated the demand for an effective way of detecting and classifying small Unmanned Aerial Vehicles (UAVs) as they pose a serious threat in civil security. We present results of radar measurements with a one channel continuous wave system at Ka band aiming at classifying UAVs through a detailed micro-Doppler analysis. High-sensitivity measurements of different UAVs...
The use of small unmanned aircraft systems (sUAS) or ‘drones’ is increasing rapidly. This has many positive benefits but also comes with safety and security risks that must be managed. These include UAS collision with manned aircraft, UAS collision with people on the ground and wider security threats such as the protection of personal privacy and terrorist activity. The “Gamekeeper” radar has been...
In this paper we design an effective Waveguide Slotted Array (WSA) antennas for K-band radar application. First of all, WSA parameters such as waveguide dimensions, slot length, slot width, slot displacement and other parameters of the antenna are calculated by using analytic techniques for 25 GHz. After, in order to suppress side lobe level Taylor and Chebyshev coefficients are determined in detailed...
Multiple-input multiple-output (MIMO) radars with wideband signals are useful to discriminate target in clutter. With wideband MIMO radar, the problem of extended target detection in compound-Gaussian clutter is considered in this paper. By obtaining target echoes from each antenna, the detector based on generalized likelihood ratio test (GLRT) is developed. It shows that the shape parameter of clutter,...
The probability of detection and the false alarm rate are the key parameters that define radar system performance. In order to obtain the best possible detection rate, while minimising false alarms, there is a need to measure and evaluate the performance of a system under development. In the case of vital signs monitoring systems, the target observation time is a very sensitive parameter. The two...
In this paper, convolutional neural networks (CNN)-based ship target recognition is studied by exploiting the targets' high resolution range profiles (HRRPs). Contrary to conventional procedures employing hand-crafted features, by designing an appropriate CNN scheme, features are learned automatically in order through convolutional layers and, recognition of military and civilian ship targets is performed...
A Forward Scatter Radar (FSR) system is clutter-limited, rather than noise limited. It does not have range resolution so the clutter is collected from the whole surface illuminated by the antenna radar. This paper introduces an approach to generate a signal with the same spectral and statistical properties of sea clutter at very low grazing angles. We proceed with a practical approach based on the...
High-frequency (HF) ocean radar systems have demonstrated their capability to capture the signal from tsunami currents after the 2011 Tohoku earthquake and tsunami. However, these systems were configured for mapping surface currents in the coastal zones and not for detecting specific patterns of tsunami waves in real-time. The WERA® ocean radar system was optimized for tsunami alerting and installed...
Amplitude and phase imbalance (IQ imbalance) seriously degrades the performance of FMCW radar systems with quadrature demodulator. The non-ideality of the radar signals has two main effects: The single-channel IQ imbalance leads to an image peak in the FMCW spectrum, resulting in wrong detections. The IQ imbalance between channels affects the direction-of-arrival (DOA) estimation, as the array manifold...
Unmanned Aerial Systems (UAS), commonly referred to as drones, are rapidly proliferating bringing about new challenges for security and safety. The reason being their small size and ability to fly low in a highly irregular manner makes them particularly difficult to detect with conventional wide-area surveillance sensors such as a scanning radar. Here, we use staring radar that employs a 2-D antenna...
The paper undertakes a problem of tracking radar and AIS fusion in maritime navigation. The focus is laid on target association process, which is the basis for track-to-track fusion. The analysis provides neural approach to association process in which neural network classifies if the association should be stated or not. The paper includes theoretical basics of the proposed approach, as well as numerical...
We present a novel method for passive radar that simultaneously reconstructs the scene reflectivity and polarimetric states of stationary targets. Our method uses a spatially sparse distribution of polarimetrically diverse receivers to measure the backscattered signal of a scene illuminated by a source of opportunity. Our data model explicitly accounts for polarization and anisotropy of the target...
In this paper, a 3-D electromagnetic inverse scattering algorithm based on analytical singular value decomposition (SVD) of the scattering integral operator is proposed. The spectral expansion of the dyadic Green's function is employed to derive continuous SVD of scattering integral operator. The analytical formulation of singular values and vectors is straightforward without considerable computation...
Mismatched processing of codes with multi-range resolution is revisited. The inverse of a binary code's spectrum is used as the transfer function of the mismatched filter. We calculate the mismatch losses for all combinations of binary codes in the range of code length L≤25 and find codes with very small mismatch loss compared with those of the conventional codes. The Doppler characteristics for various...
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