• Journal of Positioning, Navigation, and Timing
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• v.7 no.1
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• pp.25-35
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• 2018

This paper describes the measurement of pulse positioning (input time) to calculate a time of arrival (TOA) that takes from transmitting a signal from the target of multilateration (MLAT) system to receiving the signal at the receiver. In this regard, this paper analyzes performances of simple threshold method and level adjust system (LAS) method, which is one of the adaptive threshold detector (ATD) methods, among many methods to calculate pulse positioning of signal received at the receiver. To this end, Cramer-rao lower bound (CRLB) with regard to pulse positioning, which was measured when signals transmitted from a transponder mounted at the target were received at the receiver, was induced and then deviation sizes with regard to pulse positioning, which was measured with simple threshold and LAS methods through MATLAB simulations, were compared. Next, problems occurring according to a difference in amplitude of signals inputted to each receiver are described when pulse positioning is measured at multiple receivers located at a different distance from the target as is the case in the MLAT system. Furthermore, LAS method to resolve the problems is explained. Lastly, this study analyzes whether a pulse positioning error occurring due to the signal noise satisfies the requirement (6 nsec. or lower) recommended for the MLAT system when using these two methods.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.2
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• pp.113-120
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• 2021

The Distance Measuring Equipment (DME) is a ground-based aircraft navigation system and is considered as an infrastructure that ensures resilient aircraft navigation capability during the event of a Global Navigation Satellite System (GNSS) outage. The main problem of DME as a GNSS back up is a poor positioning accuracy that often reaches over 100 m. In this paper, a novel approach of applying deep reinforcement learning to a DME pulse design is introduced to improve the DME distance measuring accuracy. This method is designed to develop multipath-resistant DME pulses that comply with current DME specifications. In the research, a Markov Decision Process (MDP) for DME pulse design is set using pulse shape requirements and a timing error. Based on the designed MDP, we created an Environment called PulseEnv, which allows the agent representing a DME pulse shape to explore continuous space using the Soft Actor Critical (SAC) reinforcement learning algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.389-392
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• 1996

We propose a method to improve repeatability positioning precision of a linear pulse motor. By using this method the systematic error which may make the precision worse can be suppressed easily. And also we show that Power OP-Amp drive system enables the accidental error to be suppressed in comparison with PWM control drive system using IGBT inverter. As a result of the suppression of systematic and accidental error, improved performance of a linear pulse motor with repetitive positioning control is shown by experimental results.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.91-96
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• 1998

This study aims to realize high precision repetitive positioning control of the linear servo motor. The authors have previously improved the repeatability positioning precision by employing a two-degree-of-freedom PID controller in the positioning control, rather than equal distance positioning, and investigates the repeatability positioning precision.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.211-214
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• 1995

A precise open-loop positioning system using linear pulse motor has been developed. The system is operated in a microstepping mode by controlling the electric current. One step of 508 .mu.m (tooth pitch of the linear pulse motor) is divided into 508 micro-steps equally. The displacement is measured with a system using a Fiezeau-type interferometer. Periodical positioning error with a period of the tooth pitch was observed in this system. Therefore, the position is corrected using the error. The error is stored into computer in advance, and the microstep current is corrected on basis of the stored data. Although the positioning error of the system without the correction was .+-.4.5 .mu.m, that with the correction was decreased to .+-.1.0 .mu.m.

• Journal of Positioning, Navigation, and Timing
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• v.5 no.4
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• pp.173-180
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• 2016

This paper presents a method to suppress multipath induced by pulses using supervised learning. In modern electronics, pulses have been used for various purposes such as communication or distance measurements. Like other signals, pulses also suffer from multipath. When a pulse and a multipath are overlapped, the original pulse shape is distorted. The distorted pulse could result in communication failures or distance measurement errors. However, a large number of samples available from a pulse can be used to effectively reject multipath by using a supervised learning method. This paper introduces how a supervised learning method can be applied to Distance Measuring Equipment. Simulation results show that multipath induced distance measuring error can be suppressed by 10 ~ 45 percent depending on the allowed pulse shape variation allowed in a standard.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.25 no.1
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• pp.1-71
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• 2021

Objectives In order to reinterpret the meaning of Inch-Bar-Cubit used by pulse diagnosis, this study investigates floating pulses of lung and heart in the Inch area, middle pulse of spleen and livers in the Bar area, and deep pulse of kidney and life gate in the Cubit area. However, some suggested that the meaning of Inch-Bar-Cubit should be interpreted in the same way as floating-middle-deep. Methods In this study, the contents of Inch-Bar-Cubit assignment of pulse diagnosis proposed by Dongeuibogam and Medical Scientist were investigated along with the existing investigation of pulse diagnosis, and their interpretation was investigated. Result and conclusion The assignment of books in Pulse diagnosis can be applied by replacing them with floating-middle-deep instead of Inch-Bar-Cubit.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.2
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• pp.75-82
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• 2016

Visible light communication (VLC) using LED lamps is suitable for implementing an indoor positioning system in an indoor environment where the global positioning system (GPS) signal does not reach. In this paper, we present an indoor positioning system for mobile robots using a VLC beacon and fuzzy rules. This system consists of an autonomous mobile robot, VLC modules, and device application software. Fuzzy rules are applied to plan the global and local paths along which the mobile robot navigates indoors. The VLC transmitter modules are attached to the wall or the ceiling as beacons to transmit their own location information. The variable pulse position modulation (VPPM) algorithm is used to transmit data, which is a new modulation scheme for VLC providing a dimming control mechanism for flicker-free optical communication. The mobile robot has a receiver module to receive the location information while performing its mission in the environment where VLC transmitters are deployed.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.4
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• pp.353-361
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• 2021

This paper presents the jamming effect on the L5 band of Global Navigation Satellite System (GNSS) by analyzing real data collected via measurement campaigns in Korea region. In fact, the L5 band is one of the dedicated bands for various satellite navigation systems such as Global Positioning System (GPS), Galileo, BeiDou (BDS), and Quasi Zenith Satellite System (QZSS). And this band is also allocated along with various systems used for aeronautical radio navigation systems (ARNS). Among ARNS, the Distance Measuring Equipment (DME) and the Tactical Air Navigation System (TACAN) are systems that transmit and receive strong power pulse signals, which may cause unintentional jamming in the reception of GNSS signals. In this paper, signals in the main lobe of GPS L5, Galileo E5a, BDS B2a, and QZSS L5 are collected in Korean region to confirm whether the jamming effect exists in the band. And then, the pulse blanking technique, which is a simple signal processing technique capable of responding to pulsed jamming, is applied to analyze the jamming effect of DME/TACAN on the L5 band.