Conference Papers
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506
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Item Nonlinear Frequency Modulated Waveform Optimization for a Cooperative Radar-Communication System(Institute of Electrical and Electronics Engineers Inc., 2021) Mahipathi, A.C.; Gunnery, S.; Srihari, P.; D'Souza, J.; Jena, P.Co-existence research related to radar and communication systems has gained significant interest in the last decade to address the spectrum scarcity issues. Designing an optimal waveform for a Joint Radar-Communication (JRC) system is an important consideration to practically realize the convergence of these two subsystems. This paper proposes a Power Ratio Constraint (PRC) based optimization technique to evaluate phase coefficients of Non Linear Frequency Modulated (NLFM) waveform for a Cooperative Radar-Communication System (CRCS). The radar waveform is optimized here using the Cramér-Rao Lower Bound (CRLB) metric in conjunction with the PRC. We investigated the spectral energy distribution, auto correlation function, and estimation rate for radar systems using optimized NLFM waveform phase coefficients. In addition, data rate for communication system is computed. Further, the simulation results shows that, proposed joint PRC-CRLB based optimization method confines the radar spectrum, reduces the delay ambiguities and enhances the information rate of CRCS. © 2021 IEEE.Item Design of Unimodular Long Length Polyphase Code for CW Radar for Doppler Tolerance(Institute of Electrical and Electronics Engineers Inc., 2021) Jena, P.; Vengadarajan, A.; Srihari, P.Most of the Continuous Wave (CW) Radars use the FMCW modulation technique to determine the range. In addition, FMCW radar uses periodic sweep for practical implementations. However, there is an increased interest in the design of the CW radar using a suitable waveform of very large Time-Bandwidth (TB) product to overcome some of the perennial problems of CW radars namely, loss due to stretch processing and Range Doppler Coupling. In this work, a modern optimization method is used to design a new class of polyphase waveforms. It includes the design and simulation of uni-modular code based on Cyclic Algorithm New (CAN) algorithms. Further, we have compared CAN-based code with other popular codes such as m-sequence, random phase, and Golomb code based on performance metrics such as Peak Sidelobe Level(PSL), Integrated Sidelobe Level(ISL), and Doppler tolerance. It is found that the CAN can be used to design long length polyphase sequence with better sidelobe performance and Doppler Tolerance. © 2021 IEEE.Item MIMO Synthetic Impulse and Aperture Radar(SIAR) for Anti-Stealth Applications(Institute of Electrical and Electronics Engineers Inc., 2022) Jena, P.; Vengadarajan, A.; Srihari, P.Anti-Stealth radar using meter wave frequency such as VHF and UHF is found to be effective against stealth targets. However, meter wave radar suffers from low angular and range resolution which does not meet the detection and tracking performance of modern microwave radar. In this paper, a new class of MIMO radar which is known as Synthetic Impulse Aperture Radar (SIAR) which uses multi-carrier orthogonal waveforms has been studied. The MIMO-SIAR uses Multiple transmitters and Multiple receivers to mitigate the angular and range resolution problem of meter wave radar such as HF, VHF and UHF radar. The study is about the use of SIAR to improve the range and angular resolution using narrow band waveforms from multiple transmitters due to scarcity of continuous gap free frequency band for radiation in meter wave and sparse Tx and Rx arrays to obtain synthetic aperture using the MIMO orthogonality principle for improved angular accuracy. We have studied multi-carrier LFM waveform with de-chirping techniques for spatial domain bandwidth synthesis. From our analysis, it is evident that the MIMO-SIAR will be the solution for anti-stealth applications in meter wave frequency with sufficient resolution in angle and range for surveillance and tracking comparable to microwave radar. © 2022 IEEE.Item LPI-Based NLFM Radar Waveform Design for a Cooperative Radar-Communication System(Institute of Electrical and Electronics Engineers Inc., 2023) Mahipathi, A.C.; Pardhasaradhi, B.; Srihari, P.; D'Souza, J.; Jena, P.This paper studies the Low Probability of Intercept (LPI) based Non-Linear Frequency Modulated (NLFM) radar waveform design approach in a Cooperative Radar-Communication System (CRCS). The crux of the LPI-based radar waveform design approach is to employ optimization methods to design the transmitted radar waveform for achieving the LPI characteristics by upholding the target detection characteristics. Here, the optimization problem is formulated subject to the Power Constraint (PC) (responsible for LPI characteristics) and Similarity Constraint (SC) (responsible for target detection) to guarantee a satisfactory performance in a CRCS. In addition, the simulation results exhibit that the proposed LPI-based NLFM radar waveform design approach provides desired characteristics needed to maintain the LPI and target detection performance in a CRCS. © 2023 IEEE.Item MIMO-SAR Image Reconstruction Experiment Using Back-Projection Algorithm with Automotive Radar for ADAS Applications(Institute of Electrical and Electronics Engineers Inc., 2024) Jena, P.; Singh, A.; Vandana, S.G.; Nandagiri, A.; Srihari, P.; Pardhasaradhi, B.; Cenkarmaddi, L.R.Synthetic aperture radar (SAR) imaging has numerous uses in surface mapping, civil infrastructure, remote sensing, and terrain monitoring. Despite the benefits of multiple input multiple outputs (MIMO) in automotive radars, they are primarily used to provide range, azimuth, and elevation information for automotive applications. Obtaining acceptable angular resolution for automotive radar is a recurring difficulty due to vehicle-to-vehicle, vehicle-to-ground, vehicle-to-guardrail, and vehicle-to-tunnel discrimination. The purpose of this work is to demonstrate MIMO-SAR for finer angular resolution utilizing the 77-GHz Texas Instruments (TI) frequency-modulated continuous wave (FMCW) AWR1642 radar. SAR and MIMO radar topologies are used to increase synthetic or virtual aperture while maintaining adequate angular resolution. SAR is used to rebuild images from experimental data, and the images are created using a backpropagation algorithm. The findings are presented for SAR, MIMO, and MIMO-SAR. Furthermore, the experimental demonstration of MIMO-SAR using 77 GHz automobile radar verifies the prior modeling results. In addition, MIMO-SAR has been shown to provide better angular resolution than SAR and MIMO approaches. This algorithm's superior performance makes it appropriate for the automotive industry to perform SAR imaging on ego-corner deployed short-range radars (SRR) to picture guard rails, crossing vehicles, and VRUs. © 2024 IEEE.