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A Real-Time and Wireless Structural Health Monitoring Scheme for Aerospace Structures Using Fibre Bragg Grating Principle
Published in Arpan Deyasi, Pampa Debnath, Asit K. Datta, Siddhartha Bhattacharyya, Photonics, Plasmonics and Information Optics, 2021
Ahsan Aqueeb, Mijia Yang, Benjamin Braaten, Ellie Burczek, Sayan Roy
A three-layer identification process for IL and ILTH analysis is introduced in this section. It is an effective and simple scheme. These layers can be integrated to effectively detect IL and ILTH in an intelligent structure, which contains a network of at least three sensors. These layers are designed in such a way that, it will be able to differentiate IL and ILTH of a structure. Now for this design to work, the network must have at least three sensors. At first, strain time histories are collected from all sensors and only three least times of arrivals related to the nearest sensors to the IL are selected for further analysis. Time of arrival (TOA or ToA) is the travel time of a (surface) wave from the point of impact to the sensor. IL can then be evaluated by using the triangulation method [4]. Here, IL is decided by minimizing the error between measured and the predicted TOAs. The output from the first layer helps in defining the sampling space. One significant challenge in this approach is finding TOAs under a noisy response. In addition, measurement of the speed of the surface wave is a complex process. For an anisotropic plate, that also depends on the wave frequency and propagation direction.
WLAN Positioning Technologies
Published in Rihai Wu, Xun Yang, Xia Zhou, Yibo Wang, Enterprise Wireless Local Area Network Architectures and Technologies, 2021
Rihai Wu, Xun Yang, Xia Zhou, Yibo Wang
It should also be noted that, because there are abundant multipath components in a radio channel in an indoor environment, fading caused by superimposition of multipath signals affects packet detection by the receiver. The positioning system focuses only on the propagation distance of the signals from the line-of-sight (LOS) path, as illustrated in Figure 6.7. If signals from the reflection path are mistakenly considered as signals from the LOS path, the time of arrival (ToA) measurement error increases. To mitigate the impact of multipath signals on the ToA measurement, the multipath components are predominantly identified by means of difference or spectrum estimation. The propagation path from where signals first arrive is selected as the LOS path, and the ToA of the LOS path is obtained. The capability of differentiating multipaths depends on the radio system bandwidth. Therefore, the higher the bandwidth, the stronger the capability and the higher the time measurement precision.
Range-Based Navigation Algorithms for Marine Applications
Published in Chao Gao, Guorong Zhao, Hassen Fourati, Cooperative Localization and Navigation, 2019
David Moreno-Salinas, Naveen Crasta, António M. Pascoal, Joaquín Aranda
Using this framework, a classical problem that arises is that of computing, based on the information contained in a EDM, the geometric configuration of points, {x1, … , xm} ⊂ ℝn apart from a rotation and a translation; see for example [8]. EDMs have found application in molecular conformation problems occurring in bioinformatics [9], dimensionality reduction in machine learning and statistics [10,11], and wireless sensor network (WSN) localization [12], to name but a few. In contrast with the above, in the present chapter we focus on techniques that allow for the computation of the absolute positions of a number of objects by measuring their ranges (distances) to a set of points with known inertial coordinates. This occurs, for example, in situations where GPS is ineffective, as in indoor and underwater robotic applications. Stated in simple terms, a range measurement is obtained by computing the so-called time of arrival (TOA), often called time of flight (ToF), defined as the travel time of a signal (acoustic or electromagnetic) from a transmitter to a receiver using the knowledge of the speed of propagation of the signal in the respective medium.
Performance analysis of parameter estimator on non-linear iterative methods for ultra-wideband positioning
Published in International Journal of Image and Data Fusion, 2023
Chuanyang Wang, Bing He, Liangliang Shi, Weiduo Huang, Liuxu Shan
During recent decades, with the development of global navigation satellite system (GNSS), people paid more and more attention to the location based on service (Wang et al. 2016). Urban dwellers spend more than 80% of their time indoors; however, the GNSS signal is nsufficiently strong to penetrate through different materials used in the construction, and also the phenomena of reflection and multipath fading limit the utility of GNSS in dense urban or in the indoor environments, which make the indoor positioning demand growing (Li and Yang 2015). In general, indoor localisation technologies include Bluetooth, WIFI, RFID, ultra-wideband (UWB) and so on. When compared with other localisation technologies, the UWB is capable of providing robust signalling, through-wall propagation and a large bandwidth that allows high-resolution ranging even in harsh environments (G et al. 2017). The UWB technology is well-suited for indoor positioning applications. In order to employ this technology, different positioning methods have been developed. Localisation systems can employ various information obtained from radio signals as well as position information of the reference nodes, such as time of arrival (TOA), time difference of arrival (TDOA), angle of arrival (AOA) and received signal strength (RSS) (Alarifi et al. 2016).
Validity and reliability of an eight antennae ultra-wideband local positioning system to measure performance in an indoor environment
Published in Sports Biomechanics, 2020
José Pino-Ortega, Alejandro Bastida-Castillo, Carlos D. Gómez-Carmona, Markel Rico-González
Different positioning measurement methods have been applied to report data from RF signals between the antennae and devices. The high amount of positioning algorithms can be classified into five main categories based on estimated measurements (Alarifi et al., 2016). Typically, with the time difference of arrival (TDOA) only one transmitter is necessary (i.e. antenna master) that requires multiple receivers to share the data and cooperate to determine the location of the transmitters. This cooperation needs significant bandwidth in comparison with other algorithms. TDOA, together with the time of arrival (TOA), offers higher accuracy relative to other algorithms because of the high time resolution of the UWB signals. So, in this study, the TDOA algorithm was used to estimate positioning.