Accurate time synchronization of ultrasonic TOF measurements in IEEE 802.15.4 based wireless sensor networks

Medina, Carlos Alberto Guerrero; Segura, José C.; Torre, Ángel de la

doi:10.1016/j.adhoc.2012.07.005

Cited by 21 publications

(6 citation statements)

References 7 publications

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“…In a wireless sensor network, such synchronization of the clocks is particularly complex. The details of this network synchronization mechanism can be found in [27]. …”

Section: Estimation Of Distances and Positioningmentioning

confidence: 99%

Ultrasound Indoor Positioning System Based on a Low-Power Wireless Sensor Network Providing Sub-Centimeter Accuracy

Medina

Segura

Torre

2013

Sensors

147

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This paper describes the TELIAMADE system, a new indoor positioning system based on time-of-flight (TOF) of ultrasonic signal to estimate the distance between a receiver node and a transmitter node. TELIAMADE system consists of a set of wireless nodes equipped with a radio module for communication and a module for the transmission and reception of ultrasound. The access to the ultrasonic channel is managed by applying a synchronization algorithm based on a time-division multiplexing (TDMA) scheme. The ultrasonic signal is transmitted using a carrier frequency of 40 kHz and the TOF measurement is estimated by applying a quadrature detector to the signal obtained at the A/D converter output. Low sampling frequencies of 17.78 kHz or even 12.31 kHz are possible using quadrature sampling in order to optimize memory requirements and to reduce the computational cost in signal processing. The distance is calculated from the TOF taking into account the speed of sound. An excellent accuracy in the estimation of the TOF is achieved using parabolic interpolation to detect of maximum of the signal envelope at the matched filter output. The signal phase information is also used for enhancing the TOF measurement accuracy. Experimental results show a root mean square error (rmse) less than 2 mm and a standard deviation less than 0.3 mm for pseudorange measurements in the range of distances between 2 and 6 m. The system location accuracy is also evaluated by applying multilateration. A sub-centimeter location accuracy is achieved with an average rmse of 9.6 mm.

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“…In a wireless sensor network, such synchronization of the clocks is particularly complex. The details of this network synchronization mechanism can be found in [27]. …”

Section: Estimation Of Distances and Positioningmentioning

confidence: 99%

Ultrasound Indoor Positioning System Based on a Low-Power Wireless Sensor Network Providing Sub-Centimeter Accuracy

Medina

Segura

Torre

2013

Sensors

147

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“…Error tolerance is much stricter in some applications involved with extremely high rate measurement; for instance, a synchronization error of less than 1-2 μs is desired for 20-kHz ultrasonic-based SHM. 12 This study is focused on SHM applications with vibration data sampled at rates ranging from tens to hundreds of hertz. In this scope, efficient strategies are essential to support high-precision synchronized sensing, targeting at an error of less than 1 ms.…”

Section: Introductionmentioning

confidence: 99%

“…Such an error can falsely indicate structural damage using mode‐shape‐based damage detection algorithms. Error tolerance is much stricter in some applications involved with extremely high rate measurement; for instance, a synchronization error of less than 1–2 μs is desired for 20‐kHz ultrasonic‐based SHM 12 . This study is focused on SHM applications with vibration data sampled at rates ranging from tens to hundreds of hertz.…”

Section: Introductionmentioning

confidence: 99%

Efficient and high‐precision time synchronization for wireless monitoring of civil infrastructure subjected to sudden events

Mechitov

Hoang

et al. 2020

Struct Control Health Monit

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The implementation of a wireless smart sensor network (WSSN) to monitor a structure subjected to sudden events (e.g., earthquakes) poses many challenges. One typical challenge is to synchronize the data from different sensors during event-triggered sensing, because each wireless sensor has its own independent clock and their triggering time is generally different and unknowable. The challenge becomes more acute when real-time data acquisition is required to support vibration control or rapid damage assessment under sudden events. Although various strategies have been proposed to achieve synchronized sensing of WSSNs, all of these strategies fall short in addressing the challenges of sudden-event monitoring. In this paper, we first proposed an efficient twostage time synchronization strategy for general structural health monitoring as a baseline and implemented it on a next-generation wireless smart sensor. Building upon the baseline method, efficient time synchronization strategies are proposed, which are fully autonomous and highly efficient for suddenevent monitoring. Two classes of events are considered: short-duration events, for example, bridge impacts, during which initial data loss issues are critical, and long-duration events, such as strong winds, which can benefit significantly from employing real-time monitoring. For short-duration events, a post-event time synchronization strategy is developed, which autonomously performs offline synchronization after measurement. For long-duration events, a real-time time synchronization strategy is proposed, which can support real-time applications under sudden events, for example, vibration control. These time synchronization strategies are experimentally validated to demonstrate the efficiency and accuracy (under 20-μs maximum error) of the proposed suddenevent synchronized sensing strategies.

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“…All motes in an IEEE802. 15.4e network are synchronized and time is split into time slots, each typically 10ms long. Time slots are grouped into a super-frame which continuously repeats over time.…”

Section: Introductionmentioning

confidence: 99%

Adaptive Synchronization in IEEE802.15.4e Networks

Stanislowski¹,

Vilajosana

Qin³

et al. 2014

IEEE Trans. Ind. Inf.

101

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Industrial low-power wireless mesh networks are shifting towards time synchronized medium access control (MAC) protocols which are able to yield over 99.9% end-to-end reliability, and radio duty cycles well below 1%. In these networks, motes use time slots to communicate, and neighbor motes maintain their clocks' alignment, typically within 1ms. Temperature, supply voltage and fabrication differences cause the motes' clocks to drift with respect to one another. Neighbor motes need to resynchronize periodically through pairwise communication. This period is typically determined a priori, based on the worst case drift.In this article, we propose a novel technique which measures and models the relative clock drift between neighbor motes, thereby reducing the effective drift rate. Instead of resynchronizing at a preset rate, neighbor motes re-synchronize only when needed. This reduces the minimum achievable duty cycle of an idle network by a factor of 10, which, in turn, lowers the mote power consumption, and extends the network lifetime. This Adaptive Synchronization is implemented as part of IEEE802.15.4e in the OpenWSN protocol stack, and is validated through extensive experimentation.

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Accurate time synchronization of ultrasonic TOF measurements in IEEE 802.15.4 based wireless sensor networks

Cited by 21 publications

References 7 publications

Ultrasound Indoor Positioning System Based on a Low-Power Wireless Sensor Network Providing Sub-Centimeter Accuracy

Ultrasound Indoor Positioning System Based on a Low-Power Wireless Sensor Network Providing Sub-Centimeter Accuracy

Efficient and high‐precision time synchronization for wireless monitoring of civil infrastructure subjected to sudden events

Adaptive Synchronization in IEEE802.15.4e Networks

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