Markov Chain‐Based Stochastic Modeling of Deep Signal Fading: Availability Assessment of Dual‐Frequency GNSS‐Based Aviation Under Ionospheric Scintillation

Sun, Andrew K.; Chang, Hyeyeon; Pullen, Sam; Kil, H.; Seo, Jiwon; Morton, Y. Jade; Lee, Jiyun

doi:10.1029/2020sw002655

Cited by 26 publications

(10 citation statements)

References 37 publications

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“…The findings of this study are valuable for GNSS-based applications that rely on scintillation indices in near real-time or real-time, providing insights into the associated uncertainty in frequency scaling. This information is particularly relevant for addressing temporary losses of scintillation index at a specific carrier frequency, as demonstrated in the example shown in Sun et al (2021). Further research can leverage these key findings to develop a scintillation monitor for real-time measurement screening purposes.…”

Section: Discussionmentioning

confidence: 93%

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Statistical Uncertainty in the Frequency Dependence of the Intensity Scintillation Index (S₄)

Sun

Rino

et al. 2023

Radio Science

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The intensity scintillation index (S4) exhibits a linear frequency dependence derived from a power law phase screen model, with the exponent determined by the phase spectral index (p). However, it is well known that a departure from linearity occurs as S4 increases and saturates under strong scatter conditions. Additionally, statistical errors over a finite time window can also cause the scintillation statistic to deviate from the power law dependence on frequency. This paper presents a parametric analysis on the deviation in the S4 frequency dependence from the power law form. This investigation focuses on the contribution of statistical uncertainty in S4 calculations to the deviation in the frequency dependence according to the selected parameters: S4 and Fresnel frequency (fF). The deviation is determined by comparing p estimates calculated from the power law relationship of S4 at different L‐band frequencies with those inferred from a model‐fitting method using a multi‐frequency global navigation satellite system scintillation data set. The results show the well‐known departure from linearity as S4 increases, and reveal increasing deviations with decreasing fF. The spectral analysis indicates that the variability at the lowest frequencies of intensity spectra contributes to the statistical errors in S4 calculations due to the finite time window, particularly when scintillations are dominated by low‐frequency contributions at low fF. Simulation results of scintillation realizations show much lower deviations with a 30‐min compared to 1‐min window. This suggests a 1‐min window can be too short for reliable S4 calculations due to statistical uncertainty, especially at low fF.

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Section: Discussionmentioning

confidence: 93%

“…This information is particularly relevant for addressing temporary losses of scintillation index at a specific carrier frequency, as demonstrated in the example shown in Sun et al. (2021). Further research can leverage these key findings to develop a scintillation monitor for real‐time measurement screening purposes.…”

Section: Discussionmentioning

confidence: 96%

Statistical Uncertainty in the Frequency Dependence of the Intensity Scintillation Index (S₄)

Sun

Rino

et al. 2023

Radio Science

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“…M UAVs are equipped with receivers capable of measuring RSS of a signal transmitted from the target. It is assumed that UAVs can estimate their own positions through their navigation systems (e.g., GNSS (Misra and Enge, 1994;Sun et al, 2021;Park et al, 2022;Seo and Walter, 2014;Lee et al, 2022b;Park and Seo, 2021;Kwak and Sung, 2018;Kim et al, 2021) or alternative navigation systems (Zhang et al, 2011;Kim et al, 2014;Lee et al, 2019;Huang et al, 2019;Jia et al, 2021;Strandjord et al, 2021;Rhee et al, 2021;Jeong et al, 2020;Kim et al, 2022;Lee et al, 2022d)). When the maximum allowable search time is limited to N seconds, the position of the m-th…”

Section: Problem Descriptionmentioning

confidence: 99%

Performance Evaluation and Hybrid Application of the Greedy and Predictive UAV Trajectory Optimization Methods for Localizing a Target Mobile Device

Lee,

Seo

2023

Preprint

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“…Global navigation satellite systems (GNSS) [1], [2], [3], [4], [5], [6], including the Global Positioning System (GPS) of the United States and Galileo of Europe, provide users with accurate position and time information using satellite-based navigation signals that can be received easily almost anywhere in an open-sky environment. Such high accuracy and wide availability have made GNSS the most widely-used…”

Section: Introductionmentioning

confidence: 99%

Low-Cost GNSS Simulators With Wireless Clock Synchronization for Indoor Positioning

Kim

Seo

2023

IEEE Access

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In regions where global navigation satellite systems (GNSS) signals are unavailable, such as underground areas and tunnels, GNSS simulators can be deployed for transmitting simulated GNSS signals. Then, a GNSS receiver in the simulator coverage outputs the position based on the received GNSS signals (e.g., Global Positioning System (GPS) L1 signals in this study) transmitted by the corresponding simulator. This approach provides periodic position updates to GNSS users while deploying a small number of simulators without modifying the hardware and software of user receivers. However, the simulator clock should be synchronized to the GNSS satellite clock to generate almost identical signals to the live-sky GNSS signals, which is necessary for seamless indoor and outdoor positioning handover. The conventional clock synchronization method based on the wired connection between each simulator and an outdoor GNSS antenna causes practical difficulty and increases the cost of deploying the simulators. This study proposes a wireless clock synchronization method based on a private time server and time delay calibration. Additionally, we derived the constraints for determining the optimal simulator coverage and separation between adjacent simulators. The positioning performance of the proposed GPS simulator-based indoor positioning system was demonstrated in the underground testbed for a driving vehicle with a GPS receiver and a pedestrian with a smartphone. The average position errors were 3.7 m for the vehicle and 9.6 m for the pedestrian during the field tests with successful indoor and outdoor positioning handovers. Since those errors are within the coverage of each deployed simulator, it is confirmed that the proposed system with wireless clock synchronization can effectively provide periodic position updates to users where live-sky GNSS signals are unavailable.INDEX TERMS Indoor navigation, GNSS simulators, clock synchronization, network time protocol (NTP).

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Markov Chain‐Based Stochastic Modeling of Deep Signal Fading: Availability Assessment of Dual‐Frequency GNSS‐Based Aviation Under Ionospheric Scintillation

Cited by 26 publications

References 37 publications

Statistical Uncertainty in the Frequency Dependence of the Intensity Scintillation Index (S₄)

Statistical Uncertainty in the Frequency Dependence of the Intensity Scintillation Index (S₄)

Performance Evaluation and Hybrid Application of the Greedy and Predictive UAV Trajectory Optimization Methods for Localizing a Target Mobile Device

Low-Cost GNSS Simulators With Wireless Clock Synchronization for Indoor Positioning

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Markov Chain‐Based Stochastic Modeling of Deep Signal Fading: Availability Assessment of Dual‐Frequency GNSS‐Based Aviation Under Ionospheric Scintillation

Cited by 26 publications

References 37 publications

Statistical Uncertainty in the Frequency Dependence of the Intensity Scintillation Index (S4)

Statistical Uncertainty in the Frequency Dependence of the Intensity Scintillation Index (S4)

Performance Evaluation and Hybrid Application of the Greedy and Predictive UAV Trajectory Optimization Methods for Localizing a Target Mobile Device

Low-Cost GNSS Simulators With Wireless Clock Synchronization for Indoor Positioning

Contact Info

Product

Resources

About

Statistical Uncertainty in the Frequency Dependence of the Intensity Scintillation Index (S₄)

Statistical Uncertainty in the Frequency Dependence of the Intensity Scintillation Index (S₄)