Conference Papers

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Author: search.filters.author.Mahipathi, A.C.Has files: No

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    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.
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    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. © 2022 IEEE.
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    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.