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B-2 Flight Test Implementation of an Ethernet Based Network System for Data AcquisitionHochner, William "Bill" 10 1900 (has links)
ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV / Northrop Grumman Corporation's B-2 Flight Test Instrumentation team is revamping its entire Data Acquisition System (DAS) to be an Ethernet based network (EBN) system that will provide simplified wiring, higher speeds, greater capacity, and control over the data. The old system became obsolete in terms of capability and maintainability. New on-board avionic systems also demand that the Flight Test Instrumentation group (INSTR) accommodate fiber and high speed Ethernet data. In addition, the footprint and location for INSTR systems and components will be moved to remote areas. INSTR engineering selected the Teletronics Technology Corporation's Ethernet networked Data Acquisition Units (DAUs), known as MnDAUs, as the core system. Prior to the first flight utilization of the new INSTR DAS will undergo extensive lab and field testing to assure flight test effectiveness and the accuracy of all necessary data products. The goal is to acquire and employ the best system available while avoiding costly lessons.
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Assisted Partial Timing Support Using Neural NetworksWännström, Linus January 2018 (has links)
Assisted partial timing support is a method to enhance the synchronization of communication networks based on the Precision Timing Protocol. One of the main benefits of the Precision Timing Protocol is that it can utilize a method called holdover through which synchronization in communication networks can be maintained, however, holdover is easily impacted by network load which may cause it to deviate from a microsecond accuracy that is required. In this project, neural networks are investigated as an aid to assisted partial timing support with the intention to combat the effects of network load. This hypothesis is to achieve this through a neural network being able to predict the offset due to time delay in the communication networks and thus being able to cancel out this effect from previous offset. Feed-forward and recurrent neural networks are tested on four different types of load patterns that commonly occur on communication networks. The results show that although some level of prediction is possible, the accuracy with which the tested neural networks provide prediction is not high enough to allow it to be used for compensation of the offset caused by the load. This with the best result reaching a mean squared error of ten microseconds squared and the requirement looked for was for where the maximum was one microsecond. This project only looked at short periods of the load patterns and future areas to investigate could be looking at longer periods of the load patterns.
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Extending the precision time protocol to a metropolitan area network : Synchronizing radio base stationsKamel, Mozhdeh January 2014 (has links)
When building various types of wide area cellular radio networks there is a need to synchronize all of the base stations within a given system. Today this is typically done by attaching a highly accurate clock to each radio base station. A GPS radio receiver is commonly used as such a clock. This thesis explores the use of the Precision Time Protocol (PTP) to provide synchronization of radio base stations, rather than the current practice of using GPS radio receivers. Advantages of utilizing PTP rather than a GPS radio receiver include the ability to easily locate radio base stations (without the need for connecting the GPS radio receiver to an antenna that has line of sight to a sufficient number of GPS satellites); the system is not vulnerable to interference with or jamming of GPS radio signals; the system is not vulnerable to spoofing of GPS radio signals, and because the new generations of radio base stations are connected to a packet based backhaul link – the system can potentially utilize the existing packet network interface (thus avoiding the need for a serial interface to the GPS receiver and a pulse per second input). At the start of this thesis project it was not known what the limits of PTP are (in terms of utilizing PTP together with radio base stations). Thus it was not clear whether PTP could be extended to much longer distances than it had originally been designed for.<p> This thesis shows that PTP can be used as an accurate timing source to synchronize base stations in networks with up to four switches between the PTP grandmaster and any PTP slave.<p> This project was performed in the Common Transport Feature department at Ericsson. / Vid konstruktion av wide area cellular radio networks finns det behov av att synkronisera samtliga basstationer inom ett givet system. Detta görs idag typiskt genom att ansluta en klocka med stor tillförlitlighet till varje basstation. En GPS radiomottagare används vanligen som klocka för detta syfte. Detta examensarbete undersöker användandet av Precisions Tid Protokoll (PTP) för att synkronisera radiobasstationer, istället för att som nu typiskt använda GPS radiomottagare. Fördelar med att använda PTP istället för GPS radiomottagare är att en radiobasstation lätt kan lokaliseras (utan att ansluta en GPS-mottagare till en antenn vilken har mottagning mot flera GPS-satelliter); systemet är inte sårbart mot interferens eller störningar av GPS radio signaler; systemet är inte sårbart mot spoofing av GPS radio signaler och på grund av att den nya generationens radiobasstationer är anslutna till ett paketförmedlande backhaul nätverk kan systemet potentiellt använda sig av det redan existerande paketförmedlande nätverksgränssnittet (och på sätt undvika ett seriellt gränssnitt mot en GPS-mottagare och en puls per sekund ingång). När detta examensarbete startades var det inte känt var gränserna för PTP låg när det gäller att använda PTP tillsammans med radiobasstationer. Det var således inte klart ifall räckvidden för PTP kunde utvidgas till mycket längre avstånd än det ursprungligen var ämnat för. Detta examensarbete syftar till att visa att PTP kan användas som tillräckligt noggrann synkroniseringskälla för basstationer i nätverk med upp till fyra nätverksswitchar mellan PTP Grand Master och PTP slav. Examensarbetet har utförts vid avdelning Common Transport Feature på Ericsson.
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Synchronized Rotor Angle Measurement of Synchronous MachinesMazur, David Christopher 31 May 2012 (has links)
A key input parameter to governor feedback control and stability protection of generators is the angle of the induced voltage internal to the generator. Current practice is to estimate this value using measurements from the terminals of the generator and mathematical models. This project aims to develop a system that would directly measure the internal angle of the generator using a rotary encoder on the shaft of the machine. This document describes the theory and experimental setup of this proposed system and outlines the test procedure of experimentation. / Master of Science
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PTP Simulator for evaluating Best TimeTransmitter Clock AlgorithmsWiggman, Hugo, Kjellén, Jonathan January 2024 (has links)
In a distributed real-time system there is often a need for time synchronization of the network’s nodes. In the telecommunications industry, this is exemplified by the implementation of 5G New Radio (NR) that uses Time Devision Duplexing (TDD) communication between the user equipment and base station in a Radio Access Network (RAN). To enable communication there exists a strict requirement of no larger error than 3 μs set by the 3rd Generation PartnershipProject (3GPP). Originally made to synchronize lab equipment, the Precision Time Protocol (PTP) has been adapted for the telecom industry’s needs. The Institute of Electrical and Electronics Engineers (IEEE) in the 1588a-2023 amendment demonstrates how PTP will not create the ideal timeTransmitter-timeReceiver hierarchy in two case studies. To address these problems a modification of the Best TimeTransmitter Clock Algorithm (BTCA) is necessary. The amendment introduces the Enhanced Accuracy Metrics TLV as an optional feature. This featureenables each clock to gain knowledge about the inaccuracy of time from its neighboring clocks.The standard BTCA does not utilize the information from this new feature in its decision mechanism. This thesis presents four new alternate BTCA and to evaluate the algorithms a network simulator was built focusing on the timeTransmitter-timeReceiver hierarchy. The simulator is proven to be useful and in a case study, the four new BTCAs are evaluated where two of them solve the issues mentioned in the 1588a-2023 amendment.
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Advanced Ethernet Clock Synchronization based on Round Trip Time ProtocolGoes, Granville Manvel January 2020 (has links)
In this master thesis project, a new protocol called the Round Trip Time (RTT) protocol is implemented and verified. It helps determine the Ethernet clock frequency offset between two communicating nodes. The detection of this offset between nodes is a way to reduce the clock synchronization error. Ethernet is the basis on which a large amount of communication takes place in the world. Either it is used for exchanging data from one device to another or to connect devices to the internet. Due to the absence of clocks being exchanged between the various Ethernet communicating nodes, clock phase and frequency offsets can be present which leads to clock de-synchronization between the various nodes and results in lower system throughput. In the telecommunication industry, synchronization error between base stations can lead to lower throughput, performance degradation and packet loss. Also, with the introduction of 5G, stringent requirements will be placed on the clock synchronization errors.Currently, the Precision Time Protocol (PTP) is used to detect and correct clock synchronization errors. The PTP implementation reduces the clock synchronization error but it is still quite large. Hence, it is necessary to find a protocol which can work together with the PTP protocol to reduce this error. This thesis will introduce a new way to determine the clock frequency offset between nodes through the implementation of the RTT protocol. Through the course of this project, the clock frequency offset was determined by the RTT protocol. By comparing the expected and the theoretical clock offsets, it was concluded that the two values were very similar. The error between the offsets was in the range of 2.349-15.687 parts per billion (ppb) of the link frequency. Thus, the RTT protocol accurately and precisely determined the clock frequency offset between two Ethernet communicating nodes. This protocol is also extended to determine the clock frequency offset between two nodes transmitting periodic signals. For future works, this protocol can be combined with the PTP protocol and a way to determine the clock phase offset will be investigated. / I detta examensarbete implementerades och verifierades ett nytt protokoll, kallat Round Trip Time (RTT)-protokollet, som hjälper till att bestämma Ethernets klockfrekvensförskjutning mellan två kommunicerande noder. Denna fastställda förskjutning mellan de två noderna är ett sätt att reducera klocksynkroniseringsfelet. Ethernet är grunden i en stor del av dagens kommunikation i världen. Antingen används det för informationsutbyte mellan två enheter, eller för att ansluta till internet. Då det saknas ett utbyte av referensklocka mellan de olika kommunikationsnoderna på Ethernet, kan det uppstå klockfasoch frekvensförskjutning som leder till att klockan desynkroniseras mellan de olika noderna och därmed ger ett minskat dataflöde. I telekommunikationsindustrin kan ett synkronisationsfel mellan basstationer leda till minskat dataflöde, sämre prestanda och paketförlust. I och med introduktionen av 5G kommer stränga krav att ställas på klocksynkronisationsfelen.För närvarande används Precision Time Protocol (PTP) för att upptäcka och korrigera klocksynkroniseringsfelen. Implementationen av PTP reducerar klocksynkroniseringsfelet, men det är fortfarande relativt stort. Därav är det nödvändigt att hitta ett protokoll som kan arbeta tillsammans med PTP för att reducera detta fel. Detta arbete kommer att introducera ett nytt sätt att bestämma klockfrekvensförskjutningen genom implementation av RTT-protokollet. I detta arbete bestämdes klockfrekvensförskjutningen av RTT-protokollet. Genom att jämföra det förväntade och faktiska värdet på klockförskjutningen kunde slutsatsen dras att de två värdena var väldigt lika. Felet var i storleksordningen av 2,349-15,687 parts per billion (ppb) i linkfrekvensen. Således bestämmer RTT-protokollet korrekt och exakt klockfrekvensförskjutningen mellan de två kommunikationsnoderna i Ethernet. Protokollet utökas också för att bestämma klockfrekvensförskjutningen mellan två noder som sänder en periodisk signal. För framtida arbete kan detta protokoll kombineras med PTP-protokollet, och det ska även undersökas ett sätt för att bestämma klockfasförskjutningen.
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Time synchronization error detection in a radio access network / Tidssynkroniseringsfel upptäckt i ett radioåtkomstnätverkMadana, Moulika January 2023 (has links)
Time synchronization is a process of ensuring all the time difference between the clocks of network components(like base stations, boundary clocks, grandmasters, etc.) in the mobile network is zero or negligible. It is one of the important factors responsible for ensuring effective communication between two user-equipments in a mobile network. Nevertheless, the presence of asymmetries can lead to faults, making the detection of these errors indispensable, especially in technologies demanding ultra-low latency, such as 5G technology. Developing methods to ensure time-synchronized mobile networks, would not only improve the network performance, and contribute towards cost-effective telecommunication infrastructure. A rulebased simulator to simulate the mobile network was built, using the rules provided by the domain experts, in order to generate more data for further studies. The possibility of using Reinforcement Learning to perform fault detection in the mobile network was explored. In addition to the simulator dataset, an unlabelled customer dataset, which consists of time error differences between the base stations, and additional features for each of its network components was provided. Classification algorithms to label the customer dataset were designed, and a comparative analysis of each of them has been presented. Mathematical algorithm and Graph Neural Network models were built to detect error, for both the simulator and customer dataset, for the faulty node detection task. The approach of using a Mathematical algorithm and Graph Neural Network architectures provided an accuracy of 95% for potential fault node detection. The feature importance of the additional features of the network components was analyzed using the best Graph Neural Network model which was used to train for the node classification task (to classify the base stations as faulty and non-faulty). Additionally, an attempt was made to predict the individual time error value for each of the links using Graph Neural Network, however, it failed potentially due to the presence of fewer features to train from. / Tidssynkronisering är en process för att säkerställa att all tidsskillnad mellan klockorna för nätverkskomponenter (som basstationer, gränsklockor, stormästare, etc.) i mobilnätet är noll eller försumbar. Det är en av de viktiga faktorerna som är ansvariga för att säkerställa effektiv kommunikation mellan två användarutrustningar i ett mobilnät. Icke desto mindre kan närvaron av asymmetrier leda till fel, vilket gör upptäckten av dessa fel oumbärlig, särskilt i tekniker som kräver ultralåg latens, som 5G-teknik. En regelbaserad simulator för att simulera mobilnätet byggdes, med hjälp av reglerna från domänexperterna, för att generera mer data för vidare studier. Möjligheten att använda RL för att utföra feldetektering i mobilnätet undersöktes. Utöver simulatordataset tillhandahölls en omärkt kunddatauppsättning, som består av tidsfelsskillnader mellan basstationerna och ytterligare funktioner för var och en av dess nätverkskomponenter. Klassificeringsalgoritmer för att märka kunddataset utformades, och en jämförande analys av var och en av dem har presenterats. Matematisk algoritm och GNN-modeller byggdes för att upptäcka fel, för både simulatorn och kunddatauppsättningen, för uppgiften att detektera felaktig nod. Metoden att använda en matematisk algoritm och GNN-arkitekturer gav en noggrannhet på 95% för potentiell felnoddetektering. Funktionens betydelse för de ytterligare funktionerna hos nätverkskomponenterna analyserades med den bästa GNN-modellen som användes för att träna för nodklassificeringsuppgiften (för att klassificera basstationerna som felaktiga och icke-felaktiga). Dessutom gjordes ett försök att förutsäga det individuella tidsfelsvärdet för var och en av länkarna med GNN, men det misslyckades potentiellt på grund av närvaron av färre funktioner att träna från.
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