Time-synchronized Wireless Sensor Network for structural health monitoring applications in railway environments

Abstract

In this work a time-synchronized Wireless Sensor Network (WSN) has been designed and implemented for a realtime Structural Health Monitoring (SHM) system for trains. Channel measurements have been done in the first place on a real operational scenario, and obtained results have been used as inputs for the design of the physical layer of the WSN. A specific Time Division Multiple Access (TDMA) MAC layer and a synchronization algorithm have also been developed for allowing a deterministic data collection and synchronized sampling, which are critical aspects in SHM applications. Performance measurements of the WSN have also been done, which have shown maximum sampling synchronization jitter values within 1 μs for sensor nodes belonging the same base station, and maximum jitter values within 2 µs for nodes of different base stations.

Towards the Internet of Smart Trains: A Review on Industrial IoT-Connected Railways

“…The propagation channel of these communications has been investigated in literature. An example of wireless channel measurement in order to characterize the propagation environment for inter-car communications is described in [ 10 ]. Moreover, a measurement and analysis of a channel considering the use of Trans European Trunked RAdio (TETRA) is presented in [ 11 ].…”

“…Another real-time WSN-based railway SHM system is presented in [ 10 ]. In such an article the researchers focused on designing a customized MAC layer and a synchronization algorithm.…”

A Survey of Channel Measurements and Models for Current and Future Railway Communication Systems

“…References Vehicle Frequency Bandwidth [11] Bus 2 + 5 GHz Passengers [12] Airplane [13] UWB [14] 2 + 5 GHz [15] Narrow band [16] 3-8 GHz UWB Passengers [17] 2 + 5 GHz [18] Wideband [19] UWB [ 2.45 GHz 100 MHz [26] 434 MHz Narrow band [27] Intravehicle [28] 2 GHz [29] 2.45 GHz Wideband Intervehicle measurements. For the large wide-body cabin of an A380 airplane with two aisles, [16] shows a reduced delay spread for UWB measurements between 3 and 8 GHz.…”

“…In order to characterize the propagation environment for intervehicle communications, a wireless channel measurement campaign was carried out in [29]. This campaign was done at La Sagra maintenance facilities in Mocejón, Spain.…”

Wireless sensor nodes for generic signal conditioning: Application to Structural Health Monitoring of wind turbines

“…This RFIC allows proprietary operation at 2 Mbps with FSK/GFSK modulation, as well as operation at 250 kbps using DSSS and OQPSK (therefore, compatible with the IEEE 802.15.4 standard). Measurements performed in [23] have indicated that spatial antenna diversity will need to be implemented to overcome flat fading in the targeted propagation environment. In this sense, a very interesting feature of ADF7242 is that it has a duplicated reception chain, which allows a straightforward implementation of antenna diversity techniques, as it is able to continuously monitor the received signals in both reception chains and select the optimum one.…”