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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
    <description></description>
    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>Defense against multi-path attacks on EV charging networks: A dependency chain analysis and DQN-BASED SOLUTION</title>
      <link>https://trid.trb.org/View/2618170</link>
      <description><![CDATA[As electric vehicle (EV) charging infrastructures evolve to become more intelligent, integrated, and interconnected, they encounter escalating cybersecurity threats. Existing studies largely emphasize single-component vulnerabilities while overlooking systemic risks arising from multi-path dependency chains. This paper conceptualizes electric vehicle charging networks as a cyber-physical system (CPS) integrated with power, communication, and control layers. To tackle the issue of multi-path attack propagation within the EV charging network, we present a risk assessment method combined with graph-based system modeling with Deep Q-Networks (DQN). The attacker’s behavior is modeled as a Markov decision process, utilizing DQN to learn optimal attack paths based on cumulative rewards. This method identifies the most vulnerable components and critical propagation pathways, facilitating the development of optimized defense strategies for the deployment of constrained security resources. Comparative experiments indicate that the proposed DQN-based defense strategy outperforms random and traditional dependency-based allocations, leading to diminished cumulative attacker rewards and enhanced network resilience through more efficient resource utilization. These findings can offer practical insights for strengthening the robustness of smart grid ecosystems against multi-stage cyberattacks.]]></description>
      <pubDate>Wed, 11 Feb 2026 09:17:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2618170</guid>
    </item>
    <item>
      <title>Array Self-Position Determination Based on Orthogonal Grid Matching Under Multipath Environments</title>
      <link>https://trid.trb.org/View/2553355</link>
      <description><![CDATA[Array self-position determination methods based on multiple emitter data can avoid significant deviations of vehicle satellite navigation in harsh environments. However, existing array self-position determination methods show decrease in performance under multipath environments. To deal with this problem, we propose an array self-position determination method based on orthogonal grid matching with the spatial differencing method. Specifically, the direction of arrival (DOA) of direct path and multipath signals are respectively estimated by array spatial differencing method. The matching accuracy is enhanced by utilizing the prior information of direct path signal. After calculating correlation coefficients of different sources, estimated angles with high correlation are then classified into the same set. Then, the noise subspace of each angle set is reconstructed and the position is estimated by grid matching with the orthogonal property between the noise subspaces and the characteristic steering vectors. The matching results of redundant angle sets are removed as non-matching items, thus averting positioning deviations. The simulation results demonstrate that the computational complexity of the proposed method is comparable to that of the signal subspace fitting (SSF). Moreover, in terms of positioning precision, the proposed method outperforms multiple signal classification with enhanced spatial smoothing (ESSMUSIC), initial signal fitting (ISF), and SSF.]]></description>
      <pubDate>Tue, 06 Jan 2026 09:16:38 GMT</pubDate>
      <guid>https://trid.trb.org/View/2553355</guid>
    </item>
    <item>
      <title>Exploiting Multipath Information for Integrated Localization and Sensing via PHD Filtering</title>
      <link>https://trid.trb.org/View/2519183</link>
      <description><![CDATA[Accurate localization and perception are pivotal for enhancing the safety and reliability of vehicles. However, current localization methods suffer from reduced accuracy when the line-of-sight (LOS) path is obstructed, or a combination of reflections and scatterings is present. In this paper, the authors present an integrated localization and sensing method that delivers superior performance in complex environments while being computationally efficient. The authors' method uniformly leverages various types of multipath components (MPCs) through the lens of random finite sets (RFSs), encompassing reflections, scatterings, and their combinations. This advancement eliminates the need for the multipath identification step and streamlines the filtering process by removing the necessity for distinct filters for different multipath types, a requirement that was critical in previous research. The simulation results demonstrate the superior performance of the authors' method in both robustness and effectiveness, particularly in complex environments where the LOS path is obscured and in situations involving clutter and missed detection of MPC measurements.]]></description>
      <pubDate>Fri, 21 Mar 2025 09:04:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2519183</guid>
    </item>
    <item>
      <title>Enhanced Cybersecurity via Smart Antenna Technology for V2X</title>
      <link>https://trid.trb.org/View/2437178</link>
      <description><![CDATA[This project is under the area of “Develop Cyber-resilient Mitigation Methods.” The main purpose of this project is developing a smart antenna system to enhance cybersecurity of vehicle-to-everything (V2X) and Cellular V2X (C-V2X) communication in 5.9 GHz frequency band. The compact and low-cost antenna system comprises a circular array of four antenna elements with specially designed patterns which support both multiple inputs multiple outputs (MIMO) and array beamforming operations. It is also capable for rejecting strong interference or jamming signals due to its specially designed antenna element patterns. This approach is superior to conventional pure MIMO antenna or phased array antenna design approaches, and thus enhancing V2X communication reliability and security. A protype of the developed antenna system design was fabricated and measured. The measurement results were compared with performance predicted from numerical model simulations with excellent agreement. The developed V2X/C-V2X antenna systems can be used with any existing V2X/C-V2X radios for communication or navigations with enhanced security against multi-path or malicious interferences.]]></description>
      <pubDate>Tue, 22 Oct 2024 15:48:38 GMT</pubDate>
      <guid>https://trid.trb.org/View/2437178</guid>
    </item>
    <item>
      <title>Joint Design of Channel Estimation and Flocking Control for Multi-AUV-Based Maritime Transportation Systems</title>
      <link>https://trid.trb.org/View/2306552</link>
      <description><![CDATA[Communication efficiency and flocking stability are two basic requirements for the application of autonomous underwater vehicles (AUVs) in maritime transportation systems. Although they are closely related, most existing flocking approaches focus on the control techniques and ignore the influence of communication efficiency. This paper presents a joint design solution to the channel estimation and flocking control for multi-AUV-based maritime transportation systems, with the consideration of path loss, shadow and multipath fading channels. A value iteration-based reinforcement learning (RL) estimator is first designed to predict the channel quality of AUVs in positions that have not yet visited. With the predicted channel quality, the authors construct an integrated optimization problem for the co-design of communication and flocking strategies. Along with this, a value iteration-based RL flocking controller is developed to achieve the co-design of channel estimation and flocking control for AUVs. It is worth mentioning that, the value iteration-based RL estimator in this paper can avoid local optimal in traditional least-squares methods, and meanwhile the flocking controller in this paper can make a balance between flocking stability and communication efficiency for AUVs. Finally, simulation and experimental results reveal that the proposed approach in this paper has superior performances by comparing with the other works. As such, their approach is more useful for marine engineer to understand and explore the maritime transportation system from the communication and control view points.]]></description>
      <pubDate>Wed, 31 Jan 2024 09:13:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2306552</guid>
    </item>
    <item>
      <title>RFS-Based Multiple Extended Target Tracking With Resolved Multipath Detections in Clutter</title>
      <link>https://trid.trb.org/View/2309167</link>
      <description><![CDATA[In the literature, the problem of point target tracking with multipath detections has been studied. However, the case of extended target tracking in a multipath environment (e.g., tracking a submarine using a high resolution sonar, tracking a vehicle in an urban environment using an imaging radar) has not been adequately addressed. If the multipath detections from a single target can be modeled and used properly, better tracking performance can be obtained in terms of accuracy, false tracks and computing time. By integrating the Random Matrix (RM) theory and the random finite set (RFS) theory, an extension of the Probability Hypothesis Density (PHD) filter, called MP-ET-PHD, is proposed in this paper to address the multitarget tracking problem with an unknown number of targets in an uncertain multipath environment with clutter. In the proposed framework, a novel multipath measurement update equation is formulated and derived. Also, a Gaussian Mixture (GM) implementation of the proposed MP-ET-PHD is presented for practical applications. Simulation results show that the proposed MP-ET-PHD can effectively handle multipath detections and yield improved tracking performance over the traditional single-path extended target trackers.]]></description>
      <pubDate>Tue, 09 Jan 2024 16:15:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/2309167</guid>
    </item>
    <item>
      <title>Performance analysis of RIS-assisted V2V communication under multipath interference</title>
      <link>https://trid.trb.org/View/2298730</link>
      <description><![CDATA[Reconfigurable Intelligent Surface (RIS) enables precise modulation and directional transmission of signals by controlling the phase and amplitude of electromagnetic waves, thus solving the problems of signal fading, multipath effects, and interference faced by conventional wireless communication systems. In this paper, the RIS-assisted vehicle-to-vehicle (V2V) communication system under multipath interference was proposed, and the precise approximation for RIS-assisted V2V communication under Nakagami-m channels was derived in detail. Then, a comprehensive analysis of the key performance metrics of the system was performed, and analytical expressions for the outage probability, average bit error rate (BER), and average channel capacity were obtained thoroughly. The authors also validate all the analytical results through simulations. Furthermore, through comparative analysis, it is evident that increasing the number of RIS reflecting elements and optimizing the communication channel environment can significantly reduce the outage probability, average BER, increase the average channel capacity, and mitigate the impact of interference sources on the system.]]></description>
      <pubDate>Fri, 22 Dec 2023 08:46:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/2298730</guid>
    </item>
    <item>
      <title>An Intelligent Path Management in Heterogeneous Vehicular Networks</title>
      <link>https://trid.trb.org/View/2294309</link>
      <description><![CDATA[Achieving reliable connectivity in heterogeneous vehicular networks is a challenging task, owing to rapid topological changes and unpredictable vehicle speeds. As vehicular communication demands continue to evolve, multipath connectivity is emerging as an important tool, which promises to enhance network interoperability and reliability. Given the limited coverage area of serving access technologies, frequent disconnections are to be expected as the vehicle moves. To ensure seamless communication in dynamic vehicular environments, an intelligent path management algorithm for Multipath TCP (MPTCP) has been proposed. The algorithm utilizes a network selection mechanism based on Fuzzy Analytic Hierarchy Process (FAHP), which dynamically assigns the most appropriate underlying network for each running application. The selection process takes into account multiple factors, such as path quality, vehicle mobility, and service characteristics. In contrast to existing solutions, the authors' proposed method offers a dynamic and comprehensive approach to network selection that is tailored to the specific needs of each service to ensure that it is always paired with the optimal access technology. The results of the evaluation demonstrate that the proposed method is highly effective in maintaining service continuity during vertical handover. By tailoring the network selection to the specific needs of each application, their path manager is able to ensure optimal connectivity and performance, even in challenging vehicular environments, delivering a better user experience, with more reliable connections, and smoother data transfers.]]></description>
      <pubDate>Tue, 28 Nov 2023 10:27:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/2294309</guid>
    </item>
    <item>
      <title>DNN-Based Approach to Mitigate Multipath Errors of Differential GNSS Reference Stations</title>
      <link>https://trid.trb.org/View/2082412</link>
      <description><![CDATA[One of the major error components of differential global navigation satellite systems is a multipath error in a reference station. This paper introduces a deep neural network based multipath modeling method. A signal to noise ratio, as well as satellite geometry, is used as a feature parameter to capture the variation of the multipath error caused by unavoidable changes in the vicinity of the reference station. The performance of the proposed method is demonstrated for both normal and varying multipath cases using experimental data. The remaining multipath error after mitigation is well bounded by the standardized error model.]]></description>
      <pubDate>Thu, 27 Apr 2023 17:13:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2082412</guid>
    </item>
    <item>
      <title>Air-to-ground real-time multimedia delivery: A multipath testbed</title>
      <link>https://trid.trb.org/View/1895843</link>
      <description><![CDATA[In this work, the authors focus their attention on real-time multimedia flows from Unmanned Aerial Vehicless (UAV) to the ground, presenting and analysing the data collected in field trials during a real testbed. The objective is assessing whether a video feed of reasonable quality can be provided to the pilot of an UAV to enable Beyond Visual Line of Sight (BVLoS) operations, by exploiting the multiple cellular operators available in the area. Three cellular networks have been jointly used in a multihoming/multipath setup, leveraging the variable coverage offered in both urban and suburban environments. Taking into account both Quality of Service (QoS) and Quality of Experience (QoE) metrics, the target parameters measured in this testbed are: latency, packet error rate, and video quality, which accounts for frames integrity, continuity, and fluidity. Data collected on the field allow to evaluate both QoS and QoE in the presence of a multipath architecture, showing how the latter, in the presence of network diversity, offer the possibility to improve the QoE at the receiver. They also design a framework to characterize the error model and to map it into a QoE model, therefore providing an analytical characterisation of a multipath channel.]]></description>
      <pubDate>Mon, 28 Feb 2022 09:53:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/1895843</guid>
    </item>
    <item>
      <title>Exchanging Bandwidth With Aperture Size in Wireless Indoor Localization - Or Why 5G/6G Systems With Antenna Arrays Can Outperform UWB Solutions</title>
      <link>https://trid.trb.org/View/1862984</link>
      <description><![CDATA[The localization of wireless devices in indoor scenarios presents a major challenge because of multipath propagation. Hence, the majority of the research community has focused on increasing the available bandwidth of localization systems, leading to the emergence of the ultra wide band (UWB) radar. However, the hardware implementation of UWB transceivers is challenging itself and, hence, their utilization in commercial low-cost wireless devices is not to be expected in the near future. Hence, instead of evaluating frequency dependent phases via UWB, the measurement of spatially distributed phases represents a valuable alternative. Therefore, this article presents a comparison of phase-difference-of-arrival (PDOA) and time-of-arrival (TOA) systems. For this purpose, the authors compare the measurement sensitivity, the effects of multipath propagation, and the hardware complexity. Based on the results, the applicability of typical position estimators is discussed. Thereby, they argue that PDOA-based localization with large receiver arrays appears to be the better choice to localize wireless devices, because it enables highly accurate positioning using narrow band signals without elaborated transmitter–receiver synchronization. To validate this, indoor localization measurements are presented and compared with UWB results in extant literature.]]></description>
      <pubDate>Mon, 27 Sep 2021 09:45:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/1862984</guid>
    </item>
    <item>
      <title>Measuring the Impact of Beamwidth on the Correlation Distance of 60 GHz Indoor and Outdoor Channels</title>
      <link>https://trid.trb.org/View/1862982</link>
      <description><![CDATA[Due to narrow beamwidth and channel sparseness, millimeter-wave receivers will detect much less multipath than their microwave counterparts, fundamentally changing the small-scale fading properties. By corollary, the de facto Rayleigh-Rice model, which assumes a rich multipath environment interpreted by the Clarke-Jakes omnidirectional ring of scatterers, does not provide an accurate description of this fading nor of the correlation distance that it predicts. Rather, a model interpreted by a directional ring of scatterers, recently proposed in seminal work by Va et al., theoretically demonstrated a strong dependence of correlation distance on beamwidth. To support Va's model through actual measurement, the authors conducted an exhaustive measurement campaign in five different environments – three indoor and two outdoor – with their 60 GHz 3D double-directional channel sounder, compiling over 36,000 channel captures. By exploiting the super-resolution capabilities of the channel sounder, they were the first, to their knowledge, to measure correlation distance as a function of continuous beamwidth. The authors showed that for narrow beamwidth, correlation was maintained for much longer distances than predicted by the Rayleigh-Rice model, validating Va's model. As the beamwidth approached omnidirectionality, with increasing number of multipath detected, the behavior indeed approached the Rayleigh-Rice model.]]></description>
      <pubDate>Mon, 27 Sep 2021 09:45:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/1862982</guid>
    </item>
    <item>
      <title>A Novel Multi-Level Integrated Navigation System for Challenging GNSS Environments</title>
      <link>https://trid.trb.org/View/1871951</link>
      <description><![CDATA[Global Navigation Satellite Systems (GNSS) is utilized to provide route guidance information to land and autonomous vehicles. The GNSS–based positioning and navigation (POS/NAV) usually suffer from satellite signal blockage, interference, and multipath in urban areas. Autonomous land vehicles are equipped with cameras, radars, and laser ranging devices. The availability of these systems provides an attractive opportunity to increase the POS/NAV system accuracy. This research focuses on the development of an integrated multi-sensor POS/NAV system capable of offering seamless positioning for autonomous land vehicles. A new multi-sensor POS/NAV module integrating both adaptive cruise control frequency modulated continuous wave (ACC-FMCW) radar (RAD), and magnetometer measurements with the reduced inertial sensor system (RISS) was designed to update the navigation system during GNSS outages. Augmenting RAD/RISS system with the magnetometer measurements produces a robust solution. The designed system is further improved by utilizing fast orthogonal search (FOS) to provide nonlinear error modeling of the residual errors associated with the RAD/RISS positioning solution in order to reduce the error growth overextended and frequent GNSS outages.The proposed systems were evaluated on several real road test trajectories involving different types of land vehicles experiencing different motion dynamics. GNSS outages of up to 10 minutes were intentionally introduced to examine the performance. The results show that the proposed methods have resulted in a significant performance improvement in the positioning accuracy that can reach more than 80% if compared to the present techniques that rely only on integrating the inertial sensor technology with GNSS.]]></description>
      <pubDate>Tue, 31 Aug 2021 16:37:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/1871951</guid>
    </item>
    <item>
      <title>GPS L1CA/BDS B1I Multipath Channel Measurements and Modeling for Dynamic Land Vehicle in Shanghai Dense Urban Area</title>
      <link>https://trid.trb.org/View/1766952</link>
      <description><![CDATA[Global navigation satellite system multipath channel modeling is important for signal simulation and error mitigation in urban scenarios. However, there have not been sufficient studies on channel statistical models for dynamic land vehicles in eastern Asian cities. This paper presents both MULTIPATH and non-line-of-sight (NLOS) channel models for GPS L1CA and BDS B1I signals. They are based on an extensive field dataset collected in the Shanghai-Lujiazui area. In addition, a method is developed to estimate multipath components and NLOS signal parameters in a dynamic channel environment. It is found that the Gamma function best fits the distribution of MULTIPATH channel delays while the exponential function is better suited for the distribution of NLOS channel delays. Both MULTIPATH and NLOS channel signals follow a linear decline average power-delay trend and a zero-mean Gaussian distribution power scattering model. The Doppler fading frequency distribution for MULTIPATH and NLOS channels can be modeled by the Gaussian function except for the MULTIPATH channel signal at the low velocity range (0~3 km/h), where an absolute exponential distribution is a better fit. The lifetime distribution for MULTIPATH and NLOS channels is represented by the generalized Pareto distribution function. These findings offer insights into the GNSS signal models in urban propagation channels and are essential to the development of accurate urban navigation systems.]]></description>
      <pubDate>Tue, 16 Mar 2021 11:24:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/1766952</guid>
    </item>
    <item>
      <title>A Novel Multipath Mitigation Technique for GNSS Signals in Urban Scenarios</title>
      <link>https://trid.trb.org/View/1694065</link>
      <description><![CDATA[In typical urban or suburban environments, multipath poses a serious threat to the accuracy of position determined by a global navigation satellite system (GNSS) receiver. In this paper, a novel multipath mitigation technique is proposed for general multipath scenarios encountered in the urban settings. In the proposed technique, a double differentiated correlation function based histogram output is used to estimate the code delay. It is shown that the proposed technique provides significant improvements over the current state of the art techniques like high resolution correlator/double delta correlator and narrow correlator. The results hold for general multipath models for the mobile-satellite channels. The performance guarantees include closed form expressions for the probability of correct delay estimate and simulation results for the average range error variation with respect to carrier to noise ratio (CNR), signal bandwidth and different channel settings.]]></description>
      <pubDate>Wed, 22 Jul 2020 14:40:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/1694065</guid>
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