International Conference on Aerospace Sciences & Aviation Technology, May 1, 2011
Radar detection procedures involve the comparison of the received signal amplitude to a threshold... more Radar detection procedures involve the comparison of the received signal amplitude to a threshold. In order to obtain a constant false-alarm rate (CFAR), an adaptive threshold must be applied reflecting the local clutter situation. This paper presents an intelligent CFAR technique based on comparing the performance of five existing CFAR processors at different target and clutter situations. The proposed intelligent CFAR processor selects the adaptive threshold which is calculated by the best CFAR processor for certain environmental condition. The selection criterion based on comparing the information contained in the guard cells to those contained in test and window cells. This comparison is done to differentiate between single target, multiple targets, and clutter transition situations. Performance comparison through the Receiver Operating Characteristic (ROC) is carried out to validate the superiority of the proposed CFAR technique at different target and clutter situations.
A Wigner Ville Distribution Based Method for Detection of Gaussian Contaminated Sinusoidal Signal in Frequency Domain
Detection and frequency estimation of sinusoidal signals from a flnite number of noisy discrete-t... more Detection and frequency estimation of sinusoidal signals from a flnite number of noisy discrete-time measurements have applications in several flelds, e.g., in sonar and Radar for moving target detection. In, Pulsed Doppler radar, a bunch of Coherent Pulse Interval (CPI) is processed to detect and estimate the frequency of sinusoidal signal corresponding to the speed of target. With the advent of Fast Fourier Transform (FFT) algorithm, the Periodogram and its variants such as Bartlett's procedure and Welch method, have been extensively in use for spectral analysis. In this paper a Wigner Ville Distribution (WVD) based new method is proposed for the detection and estimation of noisy sinusoidal signals in frequency domain. The Cross terms produced due to the bilinear nature of WVD are eliminated. The proposed method outperforms the Periodogram and its variants (Bartlett and Bartlett-based method proposed by reference (2)) for ofi-bin frequencies. The performance is found to be comparable in case of in-bin frequencies. Due to Low-sidelobes reported by WVD, no additional window operation is used, consequently the proposed method outperforms the windowed version of Periodogram and its variants for all 'in' and 'ofi' bin frequencies. Also, frequency resolution remains intact. However, the issue of increased computation of proposed method can be tackled by using high speed devices and many proposed real time WVD implementation algorithms. Performances of the proposed WVD based method and the other mentioned methods are evaluated through computer simulations by generating Receiver Operating Characteristics (ROCs) via Monte Carlo trials.
Radar detection and speed estimation of high‐speed targets using phase‐modulated waveforms
Electronics Letters
Specifying parameters of high‐speed targets as range and velocity in radar systems operating with... more Specifying parameters of high‐speed targets as range and velocity in radar systems operating with phase‐modulated signals is a problematic process because of the serious effect of high Doppler frequency on these types of waveforms. In the existence of a high‐speed target, its Doppler frequency will be very high such that it totally changes the phase sequence of the received signal. As a result, the matched filter output will be distorted. Therefore, estimating target parameters will be impossible. In this letter, a new method is proposed for detecting and estimating velocity of high speed targets using phase‐modulated signals. The suggested technique methodology depends on compensating the target high‐Doppler frequency for signal recovery using a customized waveform shape. Moreover, the Doppler frequency value is estimated without ambiguity from one pulse, and without the need for a range‐Doppler module. As such, the implementation of the proposed method is simple and inexpensive. T...
Protective oxide layers on Ti-6Al-3Mo-2Nb-2Sn-2Zr-1.5Cr (TC21) alloy with equiaxed microstructure... more Protective oxide layers on Ti-6Al-3Mo-2Nb-2Sn-2Zr-1.5Cr (TC21) alloy with equiaxed microstructure considerably influence micro-hardness and hot corrosion resistance. The present work’s thermal oxidation of TC21 alloy was performed at 600, 700, and 800 °C for 5, 20, and 50 h durations. Hot corrosion methods in NaCl and NaCl + Na2SO4 salt media were applied to raw (unoxidized) and oxidized samples at 600 and 800 °C for 50 h. Hot corrosion was conducted at 600 °C for 5 cycles with 10-h steps. The best oxide layer thickness was observed at 800 °C, which increased with increased oxidation time and temperature. The surface hardness of the oxide layer at 800 °C was 900 ± 60 HV0.05 owing to the formation of TiO2 and Al2O3 phases. Raw material hardness was 342 ± 20 HV0.05, increasing threefold due to thermal oxidation. In the case of NaCl, weight loss dominated all samples except at 800 °C for 5 h. In the case of NaCl + Na2SO4, weight gain occurred at 600 and 800 °C for 5 h. Weight loss occu...
Design and Implementation of LFMCW Radar Signal Processor for Slowly Moving Target Detection Using FPGA
2020 12th International Conference on Electrical Engineering (ICEENG)
Frequency Modulated Continuous Wave (FMCW) radar has extensive areas of application for both civi... more Frequency Modulated Continuous Wave (FMCW) radar has extensive areas of application for both civil and military use due to its good performance and detection capabilities. FMCW radar signal processing is based on two main modules; Moving Target Indicator (MTI) and Two-Dimensional Fast Fourier Transform (2D-FFT). Detection performance of FMCW radar is degraded due to the attenuation of the signals come from slowly moving targets with small visible Doppler frequencies. Also, the detection degradation of the targets whose beat frequency do not lie on the FFT grids. These problems have been introduced and overcome. In this paper, a complete design and implementation of LFMCW radar signal processor incorporating the solution of these problems are introduced on a field programmable gate array (FPGA) to facilitate real time processing. Simulation and experimental measurement are found to be identical illustrating the capability of the applied methods. The hardware implementation includes generation of the digital sawtooth waveform, Dechirping process,2D_FFT processing, Windowing, MTI, Single Delay Line Integrator and off pin filter.
In the current study on TC21 Ti-alloy (6.5Al-3Mo-1.9Nb-2.2Sn-2.2Zr-1.5Cr), the thermal oxidation ... more In the current study on TC21 Ti-alloy (6.5Al-3Mo-1.9Nb-2.2Sn-2.2Zr-1.5Cr), the thermal oxidation formed oxide layers that considerably influenced mechanical properties (hardness and wear). The corrosion of raw and oxidized specimen by NaCl-induced hot salt was also examined. TC21 alloy specimens were oxidized at 600, 700, 800, and 900°C for 5, 20, and 50 h. Salt spray test was utilized on raw and oxidized (600°C /50 h & 800°C/50 h) specimens of salt corrosion evaluated at 600°C for cycling 5, 10, 20, 30, 40, and 50 h. Average thickness of the layer grew with increasing oxidation time and temperature. Thin oxide layer (average 0.16 µm) was generated by oxidation temperature at 600°C duration 5 h. at 800°C oxide layer thickness was 10.8 µm large layer. Most significant surface hardness was 1108 HV0.5 which is produced for an oxidized layer at 900°C. However, lowest hardness of 360 HV0.5 was recorded for raw materials. The best wear resistance had at 800°C specimens, while raw ones had...
FPGA implementation of pulsed noise interference against LFM radar
2017 12th International Conference on Computer Engineering and Systems (ICCES), 2017
Linear Frequency Modulation Pulse Compression LFM-PC radars have high processing gain make it dif... more Linear Frequency Modulation Pulse Compression LFM-PC radars have high processing gain make it difficult to be jammed. Classical noise jammer needs a massive power to affect the LFM radar detection capability which is not practical in modern jammers. This paper introduces a FPGA implementation of prototype noise jammer using pulsed noise jamming techniques to jam LFM with adequate power. Furthermore a complete LFM PC radar model is introduced for jammer evolution purpose. Firstly, the designed jamming technique is simulated in SystemVue environment and secondly Xilinx ISE 14.7 Design tool. Xilinx FPGA board and 4DSP DAC card are used for hardware implantation. The selected FPGA board is Kintex-7 (xc7k325t-2ffg900) and the chosen DAC board is FMC-150. The implementation results for the model in jamming free environment and under the effect of pulsed noise interference agreed with the simulation and earlier model results.
International journal of engineering research and technology, 2015
In the present paper, a proposed method for protecting the transmission of Joint Photographic Exp... more In the present paper, a proposed method for protecting the transmission of Joint Photographic Expert Group2000 (JPEG2000) images over Low Earth Orbit (LEO) remote sensing satellite based on Unequal Power Allocation (UPA) is presented. The proposed method depends on mixing the benefits of the hierarchical structure of (JPEG2000) and the fact of the variation in the received signal power due to LEO specification. The proposed method increases the quality of received images at satellite ground station by transmitting the Region of Interest (ROI) and headers (markers and marker segments) of the JPEG2000 image when the received power level is maximum, according to link budget calculation. Other compressed data bits are transmitted during the remaining satellite communication session period. A digital communication system which incorporates a Binary Phase Shift Keying (BPSK) as a common modulation technique and hamming code as channel coding method is built for the purpose of verifying th...
Proceedings of ICICS, 1997 International Conference on Information, Communications and Signal Processing. Theme: Trends in Information Systems Engineering and Wireless Multimedia Communications (Cat. No.97TH8237)
The presence of free moving metallic particles and discharges deteriorates the insulation strengt... more The presence of free moving metallic particles and discharges deteriorates the insulation strength of a compressed SF, (Sulpher-hexa fluoride) Gas Insulated Switchgear (GIS) and causes serious limitation in its practical application. Free moving metallic particles and other defects inside GIS cause partial discharge (PD) which can degrade insulating properties of insulant gas SF, to such an extent that breakdown may occur in GIS system. So, it is necessary to detect partial discharge in GIS at an early stage before the system failure and extensive damage to the equipment and the rest of the power system. Partial discharge emits acoustic signals which can be detected by applying an acoustic emission sensor (AE sensor) outside the GIS chamber. This paper initially describe some fundamental aspects as related to PD detection. Finally development of acoustic PD detection system and some experimental investigation have also presented. sensitivity to most common defects and immunity to electromagnetic interference (EMI) . The characteristics of acoustic signal from defects in GIS are the basis for the choice of test procedure and instrumentation. The test instrument should be simple, portable and easy to use. Also it should not pose any hazard to the operating personnel and equipment. A portable PD detector has been developed that can detect acoustic signal from PD and metallic particle inside GIs. The main objective of this paper is to provide a theoretical and practical basis for PD detection in GIS using acoustic technique. Acoustic PD detection is based on detection of acoustic signals emitted from partial discharges and free moving metallic particles bouncing on the CIS chamber floor. The acoustic signals inside CIS have broad bandwidth and acoustic signals generated by partial discharges or metallic
IOP Conference Series: Materials Science and Engineering, 2019
Field Programmable Gate Arrays (FPGAs) are best suited for signal processing applications that re... more Field Programmable Gate Arrays (FPGAs) are best suited for signal processing applications that require real-time processing. Therefore, it is preferred over DSP processors in implementing radar receivers that processes incoming continuous stream of data. In the past, implementing complex arithmetic operations in floating point representation was a monopoly on DSP processors and the designers had to work around the sequential nature of the DSP processor to make it suitable for real-time applications by using buffered and multi-clocking designs. But nowadays, the great advances in FPGA design technology minimized this design effort since it is capable of performing these complex algorithms in real time. This paper represents the design and implementation of an advanced radar signal processor for binary phase-coded pulsed radar incorporating a time range side lobes suppression technique on a single FPGA chip. The proposed hardware design includes a waveform generator, an advanced signa...
IOP Conference Series: Materials Science and Engineering, 2019
Pulse Compression (PC) is applied in radar systems to enhance range resolution and simultaneously... more Pulse Compression (PC) is applied in radar systems to enhance range resolution and simultaneously preserve a high duty cycle. PC phase coded radars suffer from unwanted side-lobes at the Matched Filter (MF) output which may mask weak nearby signals. Different methods have been applied to deal with this problem. Each method is designed and applied particularly for certain phase coded signal. In this paper, a generic mathematical formula for a Side-Lobe Cancelling (SLC) Optimum Filter (OP-F) in phase coded pulse compression waveforms is presented. The derived filter followed the MF and can be applied to any type of phase coded signals with any length. The validity of the derived formula is verified for Barker, polyBarker and polyphase coded signals. The enhanced detection performance of the OP-F over MF alone is verified though receiver detection curves. Also, Implementation issues of the OP-F in either time and frequency domain are discussed.
IOP Conference Series: Materials Science and Engineering, 2019
Frequency Modulated Continuous Wave (FMCW) radars get target range and Doppler information by ext... more Frequency Modulated Continuous Wave (FMCW) radars get target range and Doppler information by extracting the target beat frequency and phase exchange based on the well-known Two-Dimensional Fast Fourier Transform (2D-FFT) processing algorithm. Target whose beat frequency does not lie on the FFT grids suffers from great detection degradation. Doubling the number of FFT points, and consequently, the hardware processing complexity is a common solution to solve this problem. In this paper, a proposed method to increase the detection performance of these targets and avoid increasing system complexity is introduced. The proposed method depends on applying a proposed filter following the first and second FFT algorithms. The filter order and weights are chosen so that only one peak form the adjacent peaks of off-pin targets are distinguished. The superiority of the proposed method over the traditional one is validated for different scenarios through the Receiver Operating Characteristic (ROC).
The International Conference on Electrical Engineering, 2014
Linear frequency modulated pulse compression (LFM-PC) radar is one of the widely used modern rada... more Linear frequency modulated pulse compression (LFM-PC) radar is one of the widely used modern radar systems. It has high immunity against conventional noise jamming due to its high processing gain. To sufficiently affect such radar, smart jamming techniques should be applied. In the last decade, different smart jamming techniques have been proposed. However, literature lacks to the analysis and evaluation of the effect of such techniques on modern radar systems. In this paper, the effect of one of the recently proposed jamming techniques, called chopping jamming, is analyzed and evaluated against LFM-PC radar depending on a typical LFM-PC verified radar model. The worthy of the application of chopping jamming on LFM-PC radar regarding to the probability of false alarm as well as radar detection is discussed and presented.
The International Conference on Electrical Engineering, 2018
One of the methods for improving maximum radar range performance is increasing the average transm... more One of the methods for improving maximum radar range performance is increasing the average transmitted power. In this paper, this objective is achieved by nesting binary phase coded waveforms with different lengths. The decoding of these nested codes leads to appearance of high sidelobes which are canceled by nesting corresponding optimum filters. The hardware structure of the encoder and sidelobes cancellation processor of these nested codes are simply realized by cascading the corresponding original Barker code filters with changing the filter length in each cascaded level.
International Conference on Aerospace Sciences and Aviation Technology, 2013
This paper presents the application of Compressive Sensing (CS) theory in radar signal processing... more This paper presents the application of Compressive Sensing (CS) theory in radar signal processing. CS uses the sparsity property to reduce the number of measurements needed for digital acquisition, which causes reduction in the size, weight, power consumption, and the cost of the CS radar receiver. Complex Approximate Message Passing (CAMP) algorithm is a fast iterative thresholding algorithm which is used to reconstruct the undersampled sparse signal and improves its Signal-to-Noise Ratio (SNR) [12][13][14][15][16]. In present work, the superiority in performance of applying the CAMP algorithm in radar signal processing compared to the Digital Matched Filter (DMF), and the simple envelope detector is proved through the Receiver Operating characteristic (ROC) curves.
International Conference on Aerospace Sciences and Aviation Technology, 2009
In this paper, a novel method of using customized (AES) variable parameters is introduced. This m... more In this paper, a novel method of using customized (AES) variable parameters is introduced. This method depends on a continuous parameters reconfiguration and a customization of each internal block. The customization depends on varying the four transformations (polynomial and affine transformations for S-Box (SB), ShiftRows (SR) transformation, and MixColumn (MC) transformation). Internal AES blocks (SB, SR, and MC) are varied each round. Further more, these blocks are randomly interconnected during each session. The ciphered output was tested using avalanche, strict avalanche, and other NIST tests. This method overcomes (ECB) mode problems which appear when there is high redundancy in the plain data and also increasing strength against brute force attacks. The proposed AES is implemented on Field programmable Gate Arrays (FPGAs).
Journal of Engineering Science and Military Technologies, 2017
Barker Phase coded signals are one of the most effective technique used in pulse compression rada... more Barker Phase coded signals are one of the most effective technique used in pulse compression radars. The main problem of using these signals is the existence of sidelobes at the output of the matched filter. These sidelobes mask nearby weak targets. Also, it degrades the overall detection performance. In the present work, a novel method to totally remove these sidelobes is presented rather than conventional sidelobes reduction methods. The superior of the proposed method is evaluated through the Receiver Operation Characteristic (ROC) curve and simulated in case of single or multiple targets scenarios.
Journal of Engineering Science and Military Technologies, 2017
This paper introduces a survey of different modern signal processing techniques used in the groun... more This paper introduces a survey of different modern signal processing techniques used in the ground penetrating radar (GPR) for an ongoing research regarding buried objects detection. Detection techniques require extremely high detection rates. In GPR, microwaves signals are transmitted until an object reflects them back, then the reflected signals are processed in order to extract information about the target. This paper discusses different techniques that provide a solution to the main problem of GPR application, which is the strong reflection from unwanted targets.
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