GPS and Galileo UTC time distribution

Powers, Edward; Hahn, Jörg

doi:10.1049/cp:20040914

Cited by 6 publications

(6 citation statements)

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“…This communication node further ensures connectivity to a cloud server where microclimatic measurement data and the results from algorithmic energy flow models [25] are stored. The communication node encompasses a WiFi router, the primary system ensuring comfortable indoor conditions, a GPS receiver that provides precise timekeeping, and a personal computer to configure and visualize the specific parameters of the indoor comfort management system [26].…”

Section: Algorithm For the Work Of The Smart System Enhancing Comfort...mentioning

confidence: 99%

Implementation of a Prediction Model in a Smart System for Enhancing Comfort in Dwellings

Zaharieva,

Georgiev,

Georgiev

et al. 2023

Electronics

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This article introduces a novel approach to ensuring optimal comfort in residential environments, using a smart system powered by predictive modeling. At its core lies a complex algorithm, presented alongside a detailed block diagram, guiding the system’s operations, which are tailored for residential comfort. The primary focus is on the time series analysis of forecasting relative humidity—a critical parameter influencing comfort in living spaces. Among the various prediction models analyzed, a model based on the Fourier equation emerged as the most efficient, accounting for approximately 81% of variances in data. Upon validation, the model showcases an impressive relative error of just ±0.1%. The research underscores the potential of leveraging advanced forecasting in optimizing devices like dehumidifiers or air humidifiers, ensuring the desired comfort while minimizing energy consumption. This innovative integration paves the way for a smarter, more sustainable residential living experience.

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Section: Algorithm For the Work Of The Smart System Enhancing Comfort...mentioning

confidence: 99%

Implementation of a Prediction Model in a Smart System for Enhancing Comfort in Dwellings

Zaharieva,

Georgiev,

Georgiev

et al. 2023

Electronics

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“…Non-synchronized clocks are independently configured and do not interact with each other; this corresponds to the free-running mode in [27,Section 4.4.1]. When clocks are synchronized, using methods like Network Time Protocol (NTP) [28], Precision Time Protocol (PTP) [29], WhiteRabbit [30], Global Positioning System (GPS) [31], the occurrence of an event, when measured with different clocks, is bounded by the time error bound (∼ 1µs or less in PTP, WhiteRabbit, and GPS; ∼ 100 ms in NTP).…”

Section: B Assumptions On the Clocksmentioning

confidence: 99%

Analysis of Dampers in Time-Sensitive Networks with Non-ideal Clocks

Mohammadpour¹,

Boudec²

2021

Preprint

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Dampers are devices that reduce delay jitter in the context of time-sensitive networks, by delaying packets for the amount written in packet headers. Jitter reduction is required by some real-time applications; beyond this, dampers have the potential to solve the burstiness cascade problem of deterministic networks in a scalable way, as they can be stateless. Dampers exist in several variants: some apply only to earliest-deadlinefirst schedulers, whereas others can be associated with any packet schedulers; some enforce FIFO ordering whereas some others do not. Existing analyses of dampers are specific to some implementations and some network configurations; also, they assume ideal, non-realistic clocks. In this paper, we provide a taxonomy of all existing dampers in general network settings and analyze their timing properties in presence of non-ideal clocks. In particular, we give formulas for computing residual jitter bounds of networks with dampers of any kind. We show that non-FIFO dampers may cause reordering due to clock non-idealities and that the combination of FIFO dampers with non-FIFO network elements may very negatively affect the performance bounds. Our results can be used to analyze timing properties and burstiness increase in any time-sensitive network, as we illustrate on an industrial case-study.

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“…Many technologies have been developed to perform the time-synchronization of a network. The most common are the use of an external time source such as a global navigation satellite system (GNSS) [16], and the use of timesynchronization protocols such as NTP [22], PTP [14], generalized PTP [21] and WhiteRabbit [15]. Each comes with various performance analyses: we can cite [17] for NTP, [23] for WhiteRabbit.…”

Section: Related Workmentioning

confidence: 99%

“…In a synchronized network, clocks meeting the above stability requirements are synchronized with each other. The synchronization can be performed using for example PTP [14], generalized PTP defined in TSN [21], NTP [46], WhiteRabbit [15] or a GNSS [16]. When synchronization is used, the timeerror function for any pair such as (H g , H i ) is bounded by the precision of the protocol.…”

Section: The Synchronized Time-modelmentioning

confidence: 99%

“…In synchronized networks, the deviations are kept within bounds, using a time-synchronization protocol or a global navigation satellite system. With timesynchronization methods such as the Precision Time Protocol (PTP) [14], WhiteRabbit [15] or the Global Positioning System (GPS) [16], the clock deviation bound is ∼1µs or less; we call such cases "tightly synchronized". Here, the clock deviation is smaller than the latency requirements of network flows (∼1ms for avionics systems), and tightly-synchronized networks are typically analyzed as if clocks would be ideal.…”

Section: Introductionmentioning

confidence: 99%

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On Time Synchronization Issues in Time-Sensitive Networks with Regulators and Nonideal Clocks

Thomas,

Boudec

2020

Preprint

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Flow reshaping is used in time-sensitive networks (as in the context of IEEE TSN and IETF Detnet) in order to reduce burstiness inside the network and to support the computation of guaranteed latency bounds. This is performed using per-flow regulators (such as the Token Bucket Filter) or interleaved regulators (as with IEEE TSN Asynchronous Traffic Shaping, ATS). The former use one FIFO queue per flow, whereas the latter use one FIFO queue per input port. Both types of regulators are beneficial as they cancel the increase of burstiness due to multiplexing inside the network. It was demonstrated, by using network calculus, that they do not increase the worst-case latency. However, the properties of regulators were established assuming that time is perfect in all network nodes. In reality, nodes use local, imperfect clocks. Time-sensitive networks exist in two flavours: (1) in non-synchronized networks, local clocks run independently at every node and their deviations are not controlled and (2) in synchronized networks, the deviations of local clocks are kept within very small bounds using for example a synchronization protocol (such as PTP) or a satellite based geo-positioning system (such as GPS). We revisit the properties of regulators in both cases. In non-synchronized networks, we show that ignoring the timing inaccuracies can lead to network instability due to unbounded delay in per-flow or interleaved regulators. We propose and analyze two methods (rate and burst cascade, and asynchronous dual arrival-curve method) for avoiding this problem. In synchronized networks, we show that there is no instability with per-flow regulators but, surprisingly, interleaved regulators can lead to instability. To establish these results, we develop a new framework that captures industrial requirements on clocks in both non-synchronized and synchronized networks, and we develop a toolbox that extends network calculus to account for clock imperfections.

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GPS and Galileo UTC time distribution

Cited by 6 publications

References 0 publications

Implementation of a Prediction Model in a Smart System for Enhancing Comfort in Dwellings

Implementation of a Prediction Model in a Smart System for Enhancing Comfort in Dwellings

Analysis of Dampers in Time-Sensitive Networks with Non-ideal Clocks

On Time Synchronization Issues in Time-Sensitive Networks with Regulators and Nonideal Clocks

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