Search

The authors consider the problem of multipath exploitation on adaptive radar detection of point-like targets in a multipath environment where a priori information is available. A new approach to exploit multipath returns with knowledge-aided adaptive target-detection regime is proposed. The authors model the received signal as the sum of direct-path and reflected-path return under the assumption of a zero-mean complex circular Gaussian noise with an unknown covariance matrix. The advantage of the proposed method is exploiting multipath returns with a priori knowledge of the reflecting environment, so that it has the knowledge of the reflected steering vector for a known actual direct-path steering vector. A Generalised Likelihood Ratio Test (GLRT) for the corresponding hypothesis testing problem is derived. It is shown that the devised detector also secures the Constant False Alarm Rate (CFAR) property regarding the unknown parameters of the noise. Performance comparison of the proposed detector with the existing well-known adaptive detectors is provided. It is presented that better-detection performance can be achieved by exploiting multipath with knowledge-aided adaptive radar. It is also observed that the devised detector has a small performance degradation in case of weak multipath return. © The Institution of Engineering and Technology 2019

2017 International Artificial Intelligence and Data Processing Symposium (IDAP) (2017 : Malatya; Turkey), In this paper, the design, analysis and numerical results of back scattering field of winged almond model with ammunition and without ammunition are presented. Simulations with using Physical Optics (PO) method in Ansys HFSS software for monostatic Radar Cross Section (RCS) were made in 1 GHz and 9 GHz. By using PO method to obtain the total scattered field received part of the radar, the body of the target is seperated into number of facets, then all these facets scattered field components are super imposed. When the electrical size of the target is twice as large as the wavelength, the order diffraction field is not considered. The fractured area from the first order will be sufficient to calculate the RCS of the target. Effects of ammunition quantity of modeled winged almon model with ammunition on RCS are compared in different frequencies.

19th International Conference on Electromagnetics in Advanced Applications (ICEAA) (2017 : Verona; Italy), In this paper, a novel technique to distinguish between multiple types of electronic circuits using nonlinear radar is presented. The transmitter transmits a single tone signal to the targets, and harmonic responses are utilized to detect and distinguish non-linear electronic devices. Contrary to previous studies, the power of the transmitted signal is swept within a determined range. Then, first five harmonics of the received signal are analyzed. We utilize the information related to the frequency content using Fourier Transforms of the received harmonics are analyzed. We show that the energy levels of the Fourier Transforms can be used to classify various nonlinear electronic devices.

IEEE Radar Conference (RadarConf) (2017 : The Westin SeattleSeattle; United States), A new approach to distinguishing electronic circuits using nonlinear/harmonic radar is presented in this paper. The radar transmits a single tone signal to the electronic circuits, consisting of nonlinear components, and exploits received harmonic response for separation. Unlike previous studies, the transmitted signal power is swept within a determined range so that the received powers at each harmonic are analyzed to capture the nonlinear characteristics. To predict the behavior of the nonlinear circuits such as diode clamper, diode limiter and full wave rectifier, certain statistical features of the received powers are analyzed. We show that the received power at the harmonics are distinctive for each circuit using Euclidean distances of features in feature space.

Conference on Sensor Signal Processing for Defence (SSPD) (2016 : Edinburgh; United Kingdom), The adaptive detection of point-like targets in the presence of multipath is considered in this article. Target return signal is modeled as the sum of direct path return and reflected path return signals under the assumption of a zero-mean complex circular Gaussian noise with an unknown covariance matrix. A new approach to exploit multipath returns in target detection with an adaptive regime is studied. The novelty of this approach is that the multipath returns are exploited with a priori knowledge of the reflecting environment, so that we have the knowledge of the reflected steering vector for a known actual direct path steering vector. As a case study, we analyze a radar-target scenario over a flat conducting surface.

7th IEEE International Workshop on Metrology for AeroSpace (MetroAeroSpace) (2020 : Virtual, Online; Italy), In this paper, a two-step model is proposed, to design an optimal radar waveform to improve the detection of point like targets over a glistening surface. In this respect, a non adaptive waveform is first transmitted and a constrained Generalized Likelihood Ratio Test (GLRT) detector is used at the receiver, which exploits multipath returns in the range cell under test, by modelling the target echo as a superposition of the direct plus the multipath returns. Besides, the clutter returns are assumed to be compound-Gaussian. The Fixed Point Estimate (FPE) algorithm is used in order to estimate the clutter in the range cell under test through the secondary data collected from the out-of-bin cells. The clutter estimates are used to design an adaptive waveform for the next transmission, in order to suppress the clutter coming from adjacent cells. The proposed GLRT is also used at the end of the second transmission for the final decision. The performance analysis results show that the proposed algorithm increases the Signal-to-Clutter Ratio (SCR) of the received signal.

16th International Conference on Electromagnetics in Advanced Applications (ICEAA) (2014 : Netherlands), The idea of spectrum sharing between radar and wireless communication systems arise because of the need for extra bandwidth for wireless communication systems. Due to strong and ever growing economic, political, social, and technological driving factors, realization of this vision is inevitable in near future. Therefore, novel solutions for the efficient and fair sharing of the spectrum is needed. In this paper, we present a concise review of the state of the art on radar and communication system coexistence and bandwidth sharing.

21st International Conference on Electromagnetics in Advanced Applications, ICEAA (2019 ; Granada, Spain), A linear model using harmonic radar to distinguish electronic devices is proposed in this article. Nonlinear characteristics of the electronic devices are captured by using power varying signals as incident waves. Three harmonics of the received powers are analyzed in harmonic space. As a major contribution of this study, power series model is employed to calculate the input-output relationship of the electronic devices. As a first in this area, we construct a linear model that relates the measurements to the vectors of parameters characterizing the nonlinear behaviors of the Electronic Circuits Under Test (ECUT). Each nonlinear circuit has a distinct response to a single-tone time-varying signal with varying power. Subsequently, a unique unknown deterministic vector of parameters can be estimated from this linear model for each device. We estimate the unique vectors of parameters using a Maximum Likelihood Estimator (MLE) in the presence of Complex White Gaussian Noise (CWGN). We show that the statistical features of the normalized estimated vectors of parameters can be used to distinguish various nonlinear electronic devices.