• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.79-80
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• 2009

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.3
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• pp.172-177
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• 2023

In this paper, 2-dimensional backtracking method for ultrasonic signals. Ultrasonic sensors are a common technology used in industrial fields as many studies have been conducted on distance measurement and indoor location tracking using transmission and reception devices in pairs. A method for tracking a signal of an arbitrary ultrasonic transmission device on a 2D plane using only a receiver of an ultrasonic signal is proposed. In order to track the ultrasonic signal, the receiver receives the signal by making at least three. The three receivers may calculate a direction and a distance using a time difference in which the ultrasound reception sound is reached. The existing method of tracking signal sources using ultrasonic waves has a problem of time synchronization of devices because the transceivers must be paired or installed independently for each sensor. In order to solve this problem, the distance of the ultrasonic receiver is minimized, and it is configured as one device. The sensor installed as one device may be processed by one operator, thereby solving the time synchronization problem. To increase time difference accuracy, high-speed 32-bit timers with high time resolution can be used to quickly calculate and track distances and directions.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.3
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• pp.111-117
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• 2008

Presentation with a projector and a laser pointer is widely used in seminar or conference. The function of a laser pointer in the presentation is just indicating a certain object. In this paper, to give a mouse-like function to a laser pointer, we implement a system that locates the track of a laser pointer. The system contains a FPGA that implements camera interface and noise filter. A software for ARM processor is programmed to analyze the spectrum of the captured image and track the pattern of a laser pointer with previously stored image. As a result, the tracking system could locate the position correctly most of time within 20m with 98% accuracy.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.1
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• pp.49-56
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• 2014

In this study, the generation efficiency of the limited area of a concentrator solar cell was increased by using a solar concentrator and a tracking device. Heat generated by the solar cell was collected using a thermal absorber for supplying hot water or heating. Thus, the concentrator solar cell system provided electricity and heat simultaneously. Tracking of the sun by detecting the sun's position, repositioning of heating device towards the east after sunset, and shutting down of system after sunset were successfully implemented using an illuminance sensor (CdS) and Simulink, a commercial software package. We performed parametric analysis of the velocity, fin installation, and entrance location with respect to the operating temperature of the concentrator solar cell. A heat transfer simulation model was developed for comparing the actual temperature profiles of the concentrator solar cell and thermal absorber, and good agreement was found between the results of the simulations and the experiments.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.1
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• pp.49-58
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• 2019

The Scientific balloon is a flight system that could recover an entire platform at the end of the mission. The recovery takes place mainly in low-density populated areas, taking into account for the possible damage to the human life and public safety. In Republic of Korea, on the other hand, marine recovery should be considered due to the dense mountainous terrain and restrictions of the peninsula. In this operating environment, the envelope must be recovered because of severe marine pollution that may occur after the splashdown. Therefore, in this study, the separation device that consists of a location tracker and the waterproof system were developed. The device includes data transmission/reception, separation, and waterproof systems which are manufactured considering the environmental condition of the Korea. The performance of the device and the trajectory of the envelope were verified by conducting a separation test of a 20km platform at a target altitude and the recovery of the zero-pressure balloon.

• Journal of Advanced Navigation Technology
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• v.26 no.2
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• pp.85-90
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• 2022

In this study, in order to test the performance of the aircraft system, a threat signal simulator that can transmit a signal similar to the actual threat to the aircraft under test with high power was designed. The high-power threat signal simulator should be able to transmit broadband (UHF band, L band, S band, X band) communication signals and radar signals, and control to transmit signals accurately directed to the aircraft through interfacing tracking radar. The signal strength of the developed equipment is 63 dBm to 93 dBm or more depending on type of signal, and the tracking precision is less than 0.1 degree, which satisfies the required performance. And it was confirmed that the antenna of the high-power threat signal simulator can accurately direct the signal to the aircraft position through the tracking radar interfacing.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.4
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• pp.411-420
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• 2016

Efforts have continued in recent years to research and develop new alternative energy sources to replace coal and oil. These days interest is exploding in new pollution-free renewable energy due to the rising prices of finite energy sources. In the field of solar energy, one of new renewable energy that has been actively researched and commercialized, research efforts have been focused on solar light energy, whose efficiency has, however, reached a saturation point already. Thus, this paper proposed a solar tracking-type parabolic heat collection device to utilize solar thermal energy rather than solar light energy. The proposed device was designed in a parabolic form to collect solar heat effectively. The investigator made its prototype by incorporating a five-axis censor-based solar tracking technology in it to sense changes to the location of the sun according to the seasons and periods. In addition, an administrator interface was designed and implemented for the efficient management of heat collection device.

• Journal of Korea Multimedia Society
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• v.16 no.2
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• pp.213-225
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• 2013

This paper proposes a design method of ball-plate robot controller using single camera and two motors to balance the ball on plate and reduce steady state control error. To design the ball-plate system, it is necessary to observe state of the ball and maintain balance of the plate. The state of the ball is tracked by using the CAMShift algorithm and position error of the ball is compensated by the Kalman filter. Balance of the plate is controlled by driving two motors and we used DC motors which has smaller measurement error. Due to surface condition of the plate or tracking error of ball's position, there are small errors remained. These errors are accumulated and disturb maintaining balance of the ball. To handle the problem, we propose a controller supplemented with an integrator.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.97-102
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• 2019

The GNSS(Global Navigation Satellite System) provides important information such as Position and Navigation, Timing(PNT) to various weapon systems in the military. as a result, applications that employ satellite navigation systems are increasing. therefore, a number of studies have been conducted to deceive the weapon systems that employ GNSS. GNSS spoofing denotes the transmission of counterfeit GNSS-like signals with the intention to produce a false position and time within the victim receiver. In order to deceive the victim receiver, spoofing signal should be synchronized with GNSS signal in doppler frequency and code phase, etc. In this paper, Civilian GPS L1 C/A spoofing signals have been evaluated and analyzed by SDR receiver.

• Journal of Advanced Navigation Technology
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• v.21 no.4
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• pp.377-385
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• 2017

The solar cell need the characteristic interpreting because the solar cell changes greatly according to the isolation, temperature and load in the photovoltaic development. Moreover, to get many energy in photovoltaic development need the position tracking of the sun according to the environment change. Also, The solar cells should be operated at the maximum power point. In this paper, I used microprocessor and sensor and designed to improve the efficiency of the photovoltaic system the photovoltaic position tracker device, and compared the normal photovoltaic system of fixed form with the photovoltaic system of solar position tracked form. Moreover, compared the catalogue of solar cell module and the simulation through a mathematics modelling with the solar cell's characteristic interpreting and composed an power conversion system with boost converter and voltage source inverter. Used the constant voltage control method for maximum power point tracking in boost converter control and, used the SPWM(Sinusoidal Pulse Width Modulation) control method in inverter control. The result was less then 5% when compared the catalogue of solar cell module and the simulation through a mathematics modelling. The boost rate of boost converter was similar to 167 % with the simulation.