Browsing by Author "Srihari, P."

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3-D radar imaging using extended 2-D range migration technique
(2018) Nagarad, S.R.; Sourabh, A.S.; Shripathi, Acharya U.; 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.
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. Â© 2017 IEEE.
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. Â© 2021 IEEE.
A GNSS Position Spoofing Mitigation Algorithm using Sparse Estimation
(Institute of Electrical and Electronics Engineers Inc., 2022) Pardhasaradhi, B.; Gunnery, G.; Mahipathi, A.C.; Srihari, P.; Cenkarmaddi, L.R.
The Global Navigation Satellite Systems (GNSS) are widespread for providing Position, Velocity, and Time (PVT) information across the globe. The GNSS usually employs the Extended Kalman Filter (EKF) framework to estimate the PVT information of the receiver. The GNSS receivers PVT information is falsified by using a mimic GNSS signals is called a spoofing attack. This paper focuses mainly to combat the spoofing attack using sparse estimation theory. A generalized mathematical model is proposed for authentic and spoofed pseudoranges at the GNSS receiver. After that, a generalized pseudorange measurement model is presented by combining the authentic and spoofed pseudorange measurements. It is assumed that, only a part of satellite signals are spoofed. Further, the GNSS receiver's state is estimated by mitigating the spoofed pseudoranges and it is formulated as a Least Absolute Shrinkage and Selection Operator (LASSO) optimization problem. The simulated results, compares the proposed LASSO based EKF algorithm with traditional EKF framework. It is observed that, the proposed algorithm suppresses the spoofing effect. Moreover, the Position Root Mean Square Error (PRMSE) of the proposed algorithm decreases by increasing the number of spoofed measurements. Â© 2022 IEEE.
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. Â© 2017 IEEE.
A High-Gain Half-Bow-Tie Antenna with Tapered Slots for Foliage Penetration Radar Application
(Institute of Electrical and Electronics Engineers Inc., 2024) Shetty, A.K.; Goud, M.G.; Kandasamy, K.; Srihari, P.; Pardhasaradhi, B.P.; Cenkarmaddi, L.R.
In this study, a compact, low-profile, high-gain half-bow-tie antenna with tapered slots is designed specifically for foliage penetration radar (FOPEN) applications. The proposed antenna design begins by vertically bisecting a conventional bow-tie antenna, followed by the addition of two vertical metal strips to enhance the operational bandwidth. To achieve effective impedance matching across the desired frequency range, two horizontal conductive strips and a central balun circuit are integrated into the design. To further optimize the antenna for integration into aerial platforms, the gain and radiation pattern are refined by incorporating two additional metal strips strategically placed on the right side of the bow-tie structure. These design modifications result in a compact antenna with dimensions of 0.43Î»x 0.4Î» x 0.005Î» where Î» is the wavelength corresponding to the lower frequency of operation. The optimized antenna achieves a realized gain of 6.5 dBi and an impedance bandwidth of 110 MHz, making it highly suitable for FOPEN applications. The enhanced gain, achieved with a single dielectric layer, demonstrates the potential of this design for efficient foliage penetration radar systems. Â© 2024 IEEE.
A Modified Strassen Algorithm based DSP Accelerated 3D Kalman Filter
(Institute of Electrical and Electronics Engineers Inc., 2023) Mohalia, V.; Srihari, P.; Reddy, S.; Reddy, G.H.; Pardhasaradhi, B.
The high-speed Kalman filter (KF) algorithms are essential for robotics, autonomous vehicle, target tracking, and other applications. The dimensions of the state vector and traditional matrix multiplication (complexity of order O(n3)) are the two main reasons for the computational time of the K F algorithm. Hence, a matrix multiplication accelerator module is needed to accelerate the KF algorithm for higher dimensions of the state vector. In this paper, modified Strassen matrix multiplication (complexity of order O(n2.80)) is utilized to increase the computational efficiency of the KF algorithm. The number of cycles is evaluated against the dimensions of the KF algorithm to illustrate the proposed methodology. After that, 2D-KF and 3D-KF algorithms targeted on DSP processor TMS320C6678 using C language to ensure real-time processing. The 3 D-K F with a state of nine consumes 19.962 ~ms, 30.47 ~ms, and 40.04 ~ms of time by employing the hybrid Strassen, Strassen, and conventional matrix multiplication. It is observed that the usage of hybrid Strassen takes only half of the time provided by conventional multiplications. Â© 2023 IEEE.
A Multiple Llyods Approach for LiDAR Point Cloud Quantization and Communication
(Institute of Electrical and Electronics Engineers Inc., 2023) Dayananda, B.N.; Achala, G.; Srihari, P.; Raju, M.K.; Vandana, G.S.; Pardhasaradhi, B.
The development and usage of drones and LiDARs have become common in forestry, archaeology, surveillance, and intruders in recent years. Even though both domains reached a very mature state, the usage, integration of LiDAR scanning from drones, security, and low bandwidth constraints are still fantasy. This paper proposed to use LiDAR on a drone to scan the area, quantize the point cloud, and communicate it to the ground station through free space communication. The purpose of open space communication rather than cloud-based solutions is to avoid related security threats. In addition, this paper uses Lloyds-based quantization to achieve optimality in the quantization scheme. Before transmitting the point cloud, it is proposed to quantize it in parallel optimal quantizers. As a result of the proposed quantizer model, we calculated the RMSE, bandwidth, and choice of communication module for this particular scenario. The quantization loss is shown in terms of RMSE, bandwidth, and channel capacity requirements depicted with some bits. RMSE value obtained in this work for the Lloyds quantization method is 0.899. The LiDAR point cloud data is transmitted to ground station with data rate of 21Mbps utilizing free space optical communication. Â© 2023 IEEE.
A Mutual Interference Mitigation Algorithm for Dense On-Road Automotive Radars Scenario
(Institute of Electrical and Electronics Engineers Inc., 2023) Kumuda, D.K.; Srihari, P.; Seshagiri, D.; Raju, M.K.; Pardhasaradhi, B.
The mmWave frequency modulated continuous wave (FMCW) radars are widely adopted in the automotive industry because they work in all weather conditions. Due to the increased on-road density of mmWave radars, the primary radar mounted on the ego vehicle faces mutual interference. The traditional detection scheme employs a one-dimension fast Fourier transform (FFT) followed by a constant false alarm rate (CFAR) on the intermediate frequency (IF) signal to get the target detections. In the case of mutual interference, the IF signals behavior is abnormal and leads to miss-detection and false detections within the traditional framework. We propose a weighted beat signal normalization algorithm on the intermediate frequency (IF) signal followed by a traditional detection scheme as a mutual interference mitigation mechanism. This methodology implementation is easy since it does not disturb any processing modules like the mixer, LPF, FFT, and CFAR blocks in the architecture. The results demonstrate that, the SINR increases by the proposed method thereby minimizing the probability of missing the target detection. Â© 2023 IEEE.
A Novel Compact Wideband Planar Antenna Design for FOPEN Radar Applications
(Institute of Electrical and Electronics Engineers Inc., 2023) Shetty, A.K.; Goud, M.; Kandasamy, K.; Srihari, P.
This paper presents a compact antenna operating in the L-band for foliage penetration (FOPEN) radar applications. The antenna structure is built using a planar technology having two dielectric layers and three metallic layers. Further, it consists of a modified near-field resonant parasitic (MNFRP) mesh structure on the top layer, an MNFRP composite Egyptian axe dipole (CEAD) placed in the middle layer, and an L-shaped dipole as a feeding element in the bottom layer. In addition, the two substrates: Roger 4003C and Roger 4350B, are sandwiched between the three metallic layers. Thereafter, the L-shaped dipole is excited separately with the MNFRP CEAD and MNFRP Mesh structure to provide resonance at two different frequencies (1.3 GHz and 1.8 GHz) in the upper portion of the L-band. Besides that, the overlapping nature of the proposed antenna structure yields enhanced bandwidth. The overall dimension of the antenna is approximately 0.41 Î» X 0.41 Î» Ã— 0.0038 Î». The simulation results reveal that the proposed antenna structure produces a 550 MHz impedance bandwidth(-10dB) with 2.13 dBi gain and achieved the voltage standing wave ratio (VSWR) of 1.12. The simulations are carried out using the computer simulation tool (CST) microwave studio suite. Â© 2023 IEEE.
A Survey on Waveform Design for Radar-Communication Convergence
(Institute of Electrical and Electronics Engineers Inc., 2024) Chakravarthi Mahipathi, A.; Pardhasaradhi, B.; Lingadevaru, P.; Srihari, P.; D'Souza, J.; Cenkarmaddi, L.R.
To provide service to an abundant number of communication users and to avoid the spectrum scarcity problem, many researchers are fascinated to work towards the convergence of radar sensing and communication systems. In addition, future intelligent systems like autonomous vehicles, Vehicle-to-everything (V2X), Unmanned Aerial Vehicles (UAV), and all smart systems are going to implement both radar and communication systems on the same platform, which motivates the researchers to focus on the development of Joint Radar-Communication Systems (JRCS). Cooperative Radar-Communication System (CRCS) and Dual Functional Radar Communication (DFRC) systems provide an opportunity for communication users to utilize radar resources without disturbing radar operation. Waveform design is essential in the development of new models and designs related to joint radar-sensing and communication systems. A cooperative radar communication system uses separate waveforms for radar and communication systems. The DFRC system uses the same waveform for radar and communication operations. So to model both joint radar communication systems one should have a clear idea regarding waveform design and its approaches. Therefore, this review paper focused on different waveform design approaches for modeling CRCS and DFRC systems. In addition, the prime objective of this review paper is to give a detailed view of the existing cooperative and dual-function waveform design approaches and provide a kick-start for new learners to work on this area. © 2023 IEEE.
Adult and Child Classification using Automotive Radar for In-cabin Monitoring
(Institute of Electrical and Electronics Engineers Inc., 2024) Sreekumar, S.; Shashank, S.K.; Srihari, P.; Vandana, G.S.; Pardhasaradhi, B.; Cenkarmaddi, L.R.
The awareness and decision-making about the unattended child or pet inside a car is one of the emerging features in autonomous vehicles as a precaution to prevent hot car death. The automotive radars can provide the Doppler and spatial information about in-cabin passengers. This paper proposes to extract the range-Doppler images from the IQ radar data and process them using CNNs to classify the passenger as an adult or child. The IWR1642 radar module is used to collect the passenger details in both space and time within the car. A novel CNN architecture is proposed by trading off the accuracy and lightweight characteristics of the network. The proposed architecture provides 97.74Â± 0.34 accuracy (with 18.32 MB size) compared to the denseNet201 of 99.13Â± 0.3 (with 71.3 MB size) accuracy. The proposed architecture is compared against the existing pre-trained models like InceptionNet, MobileNet, EfficientNet, NASNet, VGGNet, DenseNet, ResNet, and Xception regarding accuracy and size. Â© 2024 IEEE.
All neighbor fuzzy relational data association for multitarget tracking in the presence of ECM
(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.
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. Â© 2016 IEEE.
An Experimental Evaluation of MIMO-SAR Imaging with FMCW Radar
(Institute of Electrical and Electronics Engineers Inc., 2022) Sriharsha Nag, T.S.; Vandana, G.S.; Pardhasaradhi, B.; Srihari, P.
Synthetic aperture radar (SAR) imaging is a widely used technique to generate two-dimensional and three-dimensional imaging based on the principle of moving sensors. This paper presents an experimental investigation of SAR imaging using an IWR6843ISK frequency modulated continuous waveform(FMCW) radar sensor on a moving platform and providing the stationary targets. In this experiment, the moving platform is used to recreate images with a higher spatial resolution based on a two-dimensional fast Fourier transform (2D-FFT) algorithm. Three different configurations are explored, namely: SAR, single input multiple output SAR (SIMO-SAR), and multiple input and multiple outputs SAR for imaging multiple targets within the vicinity. The real-time data is collected by moving the radar from 1-21m and observing two different stationary targets. The received data is processed using the 2D-FFT algorithm and obtaining the imaging for various configurations. The experimental results reveal that target detection is accomplished for all three configurations and comparable with ground truth. The MIMO-SAR outperforms and is a suitable candidate for automotive SAR imaging. Â© 2022 IEEE.
Analysis of 5G new radio waveform as an illuminator of opportunity for passive bistatic radar
(Institute of Electrical and Electronics Engineers Inc., 2021) Lingadevaru, P.; Pardhasaradhi, B.; Srihari, P.; Sharma, G.V.K.
Passive radar detects targets using the reflections of electromagnetic signals illuminated by unintended sources of opportunity in the given surveillance region. The illuminators of opportunity (IOO) like FM, DVB, DAB, LTE, WiMax, and radio frequency signals are used for the passive radar depending on the availability, frequency of operation and, type of application. This paper proposes the upcoming 5G New Radio waveform (5G NR) as an IOO for passive bistatic radar. The 5G NR waveform is used to perform parametric analysis of passive bistatic radar. The radar parameters like range resolution, velocity resolution, range product, maximum unambiguous PRF, and Cassini's ovals are investigated. Further, the 5G NR IOO is compared against existing LTE and other IOOs. Simulation results reveals that all the radar parameters are outperforming for the 5G NR waveform, claiming that 5G NR is a potential candidate for the future IOO. Â© 2021 IEEE.
Analysis of real-time tracking filters implementation in FPGA
(2019) 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 ??? filter are implemented to validate the proposed approach. � 2018 IEEE.
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 Î±Î²Î³ filter are implemented to validate the proposed approach. Â© 2018 IEEE.
Automotive Radar Signal Authentication via Correlation and Power Spectral Density
(Institute of Electrical and Electronics Engineers Inc., 2024) Vishnu Prasad, P.; Vandana, G.S.; Nandagiri, A.; Srihari, P.; Pardhasaradhi, B.; Cenkarmaddi, L.R.
Because of their comprehensive target detection, classification, and tracking capabilities, mm-wave radars are becoming increasingly popular in advanced driver assistance systems (ADAS). Unfortunately, these radars are vulnerable to attacks such as jamming and spoofing. This research presents a simple and low-cost radar signal authentication method that can be used in automotive radar receivers that lack external hardware or networking systems. The proposed technique of detecting correlation and power spectral density (PSD) classifies incoming signals as interference-free or not, and it may be swiftly implemented via a firmware update. As an example, the Texas Instruments (TI) IWR1642 frequency modulated continuous wave (FMCW) radar is tested in both non-jamming and jamming situations. The return signals are processed to get the correlation and power spectral density (PSD) observations and thereby classify the signals. Â© 2024 IEEE.
Bistatic Inverse Synthetic Aperture Radar Imaging of Automotive Targets at Millimeter Frequencies
(Institute of Electrical and Electronics Engineers Inc., 2023) Kumar, S.A.; Ram, S.S.; Srihari, P.
High-resolution inverse synthetic aperture radar (ISAR) images of road vehicles at millimeter wave frequencies provide useful information regarding the size, shape, number of wheels, and nature of the target trajectory. They are thus effective features for target classification. However, in some geometrically adverse scenarios, it may not be possible to generate ISAR images in monostatic radar conditions. Here, bistatic ISAR images generated from well separated transmitting and receiving antennas may overcome the limitations of the monostatic geometry or supplement the information obtained from monostatic radar. In this paper, we present the bistatic ISAR radar images of a car from multiple orientations and aspects. The radar data are gathered from simulations using computer-animated design models of the car along a turning trajectory. Electromagnetic modeling of the radar scattering combines a point scatterer model of the extended automotive target along with shadowing based on ray tracing. Â© 2023 IEEE.