Jul 2026· Signal Processing and Communications Applications Conference· pp. 1-4· 0 citations· 8 references
Abstract
Global Positioning System (GPS) signals in the L1 band are inherently vulnerable to both intentional and unintentional jamming because of their low received power levels. In this study, the performance of three different adaptive filtering algorithms is investigated against five representative jammer types in a GPS L1 receiver employing a single-element patch antenna. The considered jammer types include continuous-wave, swept, pulsed, wideband, and Binary Phase Shift Keying (BPSK)-modulated interference. The evaluated algorithms comprise the Least Mean Squares (LMS), Recursive Least Squares (RLS), and Adaptive Notch Filter-based approaches. Simulation-based assessments are carried out in terms of signal-to-noise-and-interference ratio improvement, bit error rate, convergence speed, and computational complexity. The results indicate that each algorithm offers distinct performance advantages depending on the characteristics of the interfering signal.
The 2483.5-2500 MHz S-band has gained increasing attention as a candidate frequency for Regional Navigation Satellite Systems (RNSS), such as Navigation with Indian Constellation (NavIC) and South Korea's Korean Positioning System (KPS). However, this band is adjacent to terrestrial services such as the Long-Term Evolution (LTE) band and the Industrial, Scientific, and Medical (ISM) band, raising concerns about interference. This study examines the impact of real-world adjacent-band interference on the reception quality of S-band RNSS signals. Two representative waveforms, BPSK(1), as used in NavIC, and a custom BOC(5,2) signal, were digitally generated and combined with real-world interference recordings obtained in the Korean spectrum environment. A software-defined radio (SDR) system was employed to process different interference and quantization scenarios. Results indicate that LTE uplinks cause the most severe degradation in carrier-to-noise density ratio (C/N₀), while microwave ovens and Wi-Fi devices also cause noticeable degradation. The BOC(5,2) waveform generally exhibited greater susceptibility to interference than BPSK(1), although the relative trend depended on the interference scenario and receiver processing configuration. Low-bit quantization increased degradation, whereas automatic gain control (AGC) partially mitigated this effect.
Hyung-Jun Hong, Subin Lee, Youngwhan Song et al.· Scientific Reports· 0 citations
The unique characteristics of Low Probability of Intercept (LPI) waveforms, which are based on wideband specialized modulation techniques, LPI signals not only provide high resistance against electronic jamming but also significantly reduce the detectability of these signals, thereby establishing LPI signals as an effective electronic countermeasure. The Chirp Spread Spectrum (CSS) waveforms used in the LoRa protocol are a current example of signals possessing LPI characteristics. In complex electromagnetic environments where spectral density is high and the signal-to-noise ratio (SNR) drops to critical levels, the detection of these signals and the separation of their sub-characteristics remain an ongoing challenge in the literature. This study presents an original time-frequency analysis approach that enables the detection of CSS signals and parameter estimation with high accuracy under the aforementioned challenging environmental conditions. In tests conducted to validate the method’s performance, CSS signals with unknown parameters were subjected to different channel scenarios by generating spectral density in a laboratory environment. The proposed method was tested on IQ (In-Phase Quadrature) signal data recorded on a Software-Defined Radio (SDR) platform; using the developed algorithm, CSS signal parameters are extracted with high accuracy even under low SNR conditions where the signal power fell below the noise floor in some cases.
Mehmet Samet Temel, Çağın Durmuş, Ömer Faruk Sariyer et al.· Signal Processing and Commun...· 0 citations
This paper considers a hybrid frequency- and phase-shift keying (FPK) waveform for integrated sensing and communications (ISAC). Compared to FSK-based ISAC waveforms in the literature, the proposed waveform shows similar local radar estimation accuracy and superior performance both in terms of data rates and radar global accuracy. The ambiguity function (AF) is used as a tool to evaluate the radar performance of the FPK waveform. We show that incorporating phase modulation into the FSK waveform generally has an insignificant effect on the sharpness of the AF main lobe while reducing the values of the peak sidelobe levels (SLs) in the AF. We also derive the Cramer-Rao lower bounds of the delay and Doppler shift estimates for the FPK waveform. Additionally, since the AF SLs vary depending on the data embedded in the waveform, we analyze and provide approximations for the distribution of the AF SLs. Finally, we analyze the error performance of both the optimal and suboptimal communication receivers, and derive the nearest-neighbors approximation for the symbol error probability using the optimal receiver. Numerical examples illustrate the accuracy of our approximations and show the performance improvements of the FPK waveform compared to FSK.
L. A. Cruz, Tian Han, Jamie S. Evans et al.· IEEE Open Journal of the Com...· 0 citations
Automotive radar is a key sensing modality in advanced driver-assistance systems. In dense traffic environments, mutual radar interference can significantly degrade detection performance. This article presents a robust moving mean filtering (MMF)-median absolute deviation (MAD)-iterative subspace projection (ISP) algorithm designed for realistic operating conditions, where multipath propagation of interference signals introduces chirp distortions. The proposed method exploits the observation that, after dechirping and low-pass filtering, noncoherent interference manifests as sudden amplitude spikes within individual chirps. Interference samples are first detected using an MAD criterion following MMF, and subsequently reconstructed via the ISP method. The proposed approach accommodates multiple interference sources as well as extended static reflectors, such as guardrails. Compared with existing methods, it achieves effective interference suppression in complex traffic scenarios while maintaining reasonable computational time. The performance of the method is validated through numerical simulations and experimental measurements.
Yu Chen, Minglei Yang, Baixiao Chen et al.· IEEE Transactions on Aerospa...· 0 citations
In modern aerial combat environments, electromagnetic interference(EMI) and jamming significantly degrade the reliability of air-to-air missile data links. This paper compares the performance of Binary Pulse Position Modulation (BPPM) and Binary Frequency Shift Keying(BFSK) under interference conditions caused by aircraft radar signals. Using a Linear Frequency Modulated(LFM) pulse train as the interference model, bit error rate(BER) performance was evaluated for J/S = 5, 10, 15 dB. Simulation results demonstrate that BFSK exhibits superior interference resistance and lower BER than BPPM due to its frequency orthogonality and temporal interference dispersion. The study provides a quantitative basis for selecting robust modulation schemes for missile–fighter communication links operating in dense electromagnetic environments.
Yeonhee Pak, Yongmin Kim, Ji-Eun Roh· Journal of the Korea Institu...· 0 citations
In military confrontations, intentional suppression jamming can significantly degrade the reliability of friendly communication systems. By integrating conventional frequency hopping with spectrum sensing, cognitive frequency hopping technology can proactively avoid jammed frequency bands, thereby enhancing anti-jamming performance. This paper proposes a jamming detection and parameter estimation algorithm based on an improved YOLOv8 model. The proposed method extracts the time–frequency features of jamming signals and predicts their bounding boxes in time–frequency images. Based on the coordinates of the predicted bounding boxes, the center frequency, bandwidth, and temporal parameters of the jamming signals are estimated, thereby supporting spectrum sensing. Simulation results under MATLAB-generated signal conditions show that the proposed method achieves high detection accuracy and low mean squared relative error in the considered simulation scenarios. In addition, the proposed method maintains effective detection and parameter-estimation performance in composite jamming scenarios. This study provides a useful simulation-based reference for spectrum sensing in cognitive frequency hopping systems.
Hangyu Yang, Zhaoran He, Lu Xu et al.· Information· 0 citations