Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
83 results
Search Results
Item MIMO radar ambiguity analysis of frequency hopping pulse waveforms(Institute of Electrical and Electronics Engineers Inc., 2014) Sharma, G.V.K.; Srihari, P.; Rajeswari, K.R.Radar systems employing multiple transmit antennas and multiple receive antennas have received great interest over the last decade. While single-input multiple-output (SIMO) radar systems employ only spatial diversity, multiple-input multiple-output (MIMO) radars employ both spatial and waveform diversity to improve the system performance. Waveform design for MIMO radars involves optimization of desired delay, Doppler and spatial resolution characteristics. Designs of frequency hopping waveforms that optimize the MIMO radar ambiguity function under small and large Doppler scenarios were recently proposed. These waveforms are obtained by optimizing an appropriately formulated cost function using modified simulated annealing algorithms. In this paper, the MIMO radar ambiguity properties of large sets of frequency hopping waveforms based on algebraic theory are analyzed and their relative performance are compared. © 2014 IEEE.Item LMS adaptation for assaying power profile delay estimation in MIMO-OFDM tactics(Institute of Electrical and Electronics Engineers Inc., 2014) Betha, B.; Kiranmayee, P.; Srihari, P.To delve the OFDM tactics is the endeavor of this paper which accompanies effectuating an outright functional system and assaying how it is minifies the inter symbol interference elicited by the multipath fading channels and discordant effects and reverencing its performance. The power delay figuring and a channel estimator connoted as mean square error (MSE) of multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) systems are both inferred. For factual pertinence, solitarily the pilot motifs related to entire transmit antenna ports have been availed for reverencing the power delay (PD). The distortion evoked by void subcarriers along with some unsufficing multitude of samples for power delay (PD) estimation is also cogitated. Proffered tactics efficaciously abates the mutilations for veracious PDP estimation plying Least Mean Square (LMS) algorithm. The results furnished evinces that the rendition of LMMSE channels estimation exerting the ID and LMS PDP estimate advents because of the diminution of mutilation chattels. © 2014 IEEE.Item Study of 2D localization using SIMO antenna(Institute of Electrical and Electronics Engineers Inc., 2016) Laddha, P.; Prasad, R.; Shripathi Acharya, U.S.; Srihari, P.; Prasad, S.; Rao, P.H.A single input and multiple output (SIMO) antenna configuration is presented for real time data acquisition. The proposed approach can provide both range and angle information in a plane. A method of localization of multiple point objects (targets) in azimuthal plane is realized by employing one stationary transmitting antenna and dynamic receiving antennas positions. FMCW chirp signals are used as transmitting signals. A parametric analysis is carried out by varying the bandwidth of transmitted signal, number of samples and number of antennas on a linear array with equal inter-element spacing. Radial resolution of 0.4 feet and 0.23 feet is achieved for 2GHz and 6 GHz bandwidths respectively. The method is extended to identify multiple targets. © 2016 IEEE.Item Blast vibration signal analysis using S-transform(Institute of Electrical and Electronics Engineers Inc., 2016) Teja, V.V.S.A.; Chaitanya, S.V.; Akula, U.; Srihari, P.; Sastry, V.R.Rock blasting in mines and quarries is an important operation meant for fragmenting and displacing the hard rock mass / strata. The unavoidable environmental effect is the ground vibration, resulting from the wastage of explosive energy. Ground vibrations travelling to far off distances may have effect on the structures. Signal processing techniques play a vital role in analyzing the velocity of ground vibration signals in rock blasting. So far, time-frequency domain is being used for analyzing the ground vibration signals. However, usage of S-Transform, we get frequency dependent resolution of time-frequency domain. It is possible to simultaneously analyze the signal using time, frequency and amplitude values obtained by applying S-transform. A case study is presented in this paper, wherein the S-Transform is applied to the ground vibration velocity signals, which helps in better understanding and analysis of the signal compared to Fourier transform and Wavelet transform techniques. © 2016 IEEE.Item All neighbor fuzzy relational data association for multitarget tracking in the presence of ECM(Institute of Electrical and Electronics Engineers Inc., 2017) Satapathi, G.S.; Srihari, P.This paper proposes a novel data association approach based on fuzzy relational clustering for multi target tracking in the presence of electronic counter measures (ECM). Likelihood values and similarity index are calculated for each observation obtained from radar. Expectation maximization technique is applied to obtain possibility association matrix. Simulation results demonstrate that, proposed method performs better, when compared to conventional joint probability association (JPDA) and fuzzy clustering (FCM) approaches in terms of position and velocity root mean square error (RMSE). Further, current approach yielded average reduction of 50.5% and 35.5% for position and velocity RMSE values respectively in case of linear crossing targets. © 2016 IEEE.Item A high speed complementary pulse compressor and its implementation of FPGA(Institute of Electrical and Electronics Engineers Inc., 2017) Kumar, K.N.L.; Srihari, P.; Satapathi, G.S.; Sharma, G.V.K.This paper proposes a novel high speed radar pulse compressor implementation for complementary sequences. The high speed implementation is accomplished by incorporating the retiming technique to reduce the critical path of the circuit. In addition, unfolding the retimed pulse compressor further increases the speed by parallel operation. This concept is implemented on field programmable gate array (FPGA) and the experimental results demonstrate that, three-retimed-unfolded circuit (J = 3) is 2.78 times faster than the original circuit. © 2017 IEEE.Item 3-D radar imaging using extended 2-D range migration technique(Institute of Electrical and Electronics Engineers Inc., 2017) Nagarad, S.R.; Sourabh, A.S.; Shripathi Acharya, U.S.; Srihari, P.; Prasad, S.; Rao, P.H.A three dimensional (3-D) imaging system is implemented by employing 2-D range migration algorithm (RMA) for frequency modulated continuous wave synthetic aperture radar (FMCW-SAR). The backscattered data of a 1-D synthetic aperture at specific altitudes are coherently integrated to form 2-D images. These 2-D images at different altitudes are stitched vertically to form a 3-D image. Numerical simulation for near-field scenario are also presented to validate the proposed algorithm. © 2017 IEEE.Item Analysis of real-time tracking filters implementation in FPGA(Institute of Electrical and Electronics Engineers Inc., 2018) Haritha, G.; Aparna., P.; Srihari, P.; Satapathi, G.S.This paper presents real time tracking hardware based on field programmable gate arrays (FPGA). Traditionally, tracking system is simulated in MATLAB environment and an equivalent hardware description language (HDL) code is written for FPGA. But, in this paper a simulated and verified MATLAB code is directly converted into HDL which is used in FPGA. This method improves the efficiency of the real time tracker and flexibility in usage of FPGA. Moreover, the simulated and hardware outputs will be consistent. Three types tracking algorithm namely Kalman filter (KF), extended Kalman filter (EKF), and αβγ filter are implemented to validate the proposed approach. © 2018 IEEE.Item Systolic-Architecture-Based Matrix Multiplications and Its Realization for Multi-Sensor Bias Estimation Algorithms(Springer Science and Business Media Deutschland GmbH, 2021) Gopala Swamy, B.; Sripati Acharya, U.; Srihari, P.; Pardhasaradhi, B.The accelerators are gaining predominant attention in the HW/SW designs and embedded designs due to the less power consumption and parallel data processing capabilities compared to standard microprocessors and FPGA’s. In this paper, MSSKF (Multi-sensor Schmidt–Kalman filter)-based coupled bias estimation problem is considered for single target multiple sensors case. Here MSSKF augments the state vector and bias vector for bias estimation, results in computationally expensive as the dimensions of the state and sensors increases. Hence to address the computational complexity, digital signal processing (DSP) architectures are proposed and accelerated the algorithm to meet the real-time constraints. In the MSSKF algorithm, the overload of the algorithm is due to state covariance prediction and innovation covariance prediction. To realize the state covariance and innovation covariance, a folded DSP architecture and parallel processing based folded DSP architecture are proposed, respectively. The matrix multiplications are addressed with systolic arrays to gain the advantage of latency and parallel processing. Moreover, MSSKF using systolic array architectures simulated and synthesized in Vivado 2018.1 using Verilog and implemented on FPGA-Zynq-7000 board. The performance of the systolic-based accelerator realization was compared with normal matrix multiplication. © 2021, Springer Nature Singapore Pte Ltd.Item A Conceptual Framework for Knowledge Aided Passive Radar System(Institute of Electrical and Electronics Engineers Inc., 2021) Lingadevaru, P.; Srihari, P.; Pardhasaradhi, B.; Gunnery, S.Significant recent radar research has been focused on knowledge aided signal processing, waveform design, detection and target tracking applications. Passive radars have the edge over active radars in spectrum utilization and covert operation for target detection and tracking applications. Passive radars generally use the existing illuminators of opportunity to detect or track the targets. The knowledge pertaining to illuminator of opportunity (IOO) selection, spectrum sensing, and diversity technique can predominantly improve the received signal strength (RSS) at the passive radar receiver. This paper proposes a Conceptual framework to build a Knowledge Aided Passive Radar System (KA-PRS) based on spectrum sensing, IOO selection, and spatial diversity. The mathematical modelling and functional blocks to build the KA - PRS are discussed. The analytical and simulation results reveal that KA-PRS provides improved signal-to-noise (SNR) ratio compared with the traditional passive radar. © 2021 IEEE.