• Journal of Institute of Control, Robotics and Systems
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• v.19 no.2
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• pp.158-163
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• 2013

The fusion of the GPS (Global Positioning System) and DR (Dead Reckoning) is widely used for position and latitude estimation of vehicles such as a mobile robot, aerial vehicle and marine vehicle. Among the many types of aerial vehicles, grater focus is given on the quad-rotor and accuracy of the position information is becoming more important. In order to exactly estimate the position information, we propose the fusion method of GPS and Gyroscope sensor using the DEKF (Dual Extended Kalman Filter). The DEKF has an advantage of simultaneously estimating state value and a parameter of dynamical system. It can also be used even if state value is not available. In order to analyze the performance of DEKF, the computer simulation for estimating the position, the velocity and the angle in a circle trajectory of quad-rotor was done. As it can be seen from the simulation results using own proposed DEKF instead of EKF on own fusion method in the navigation of a quad-rotor gave better performance values.

• Ocean Systems Engineering
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• v.9 no.4
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• pp.391-407
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• 2019

Tracking the location (position) of a surface or underwater marine vehicle is important as part of guidance and navigation. While the Global Positioning System (GPS) works well in an open sea environment but its use is limited whenever testing scaled-down models of such vehicles in the laboratory environment. This paper presents the design, development and implementation of a low energy ultrasonic augmented single beacon-based localization technique suitable for such requirements. The strategy consists of applying Extended Kalman Filter (EKF) to achieve location tracking from basic dynamic distance measurements of the moving model from a fixed beacon, while on-board motion sensor measures heading angle and velocity. Iterative application of the Extended Kalman Filter yields x and y co-ordinate positions of the moving model. Tests performed on a free-running ship model in a wave basin facility of dimension 30 m by 30 m by 3 m water depth validate the proposed model. The test results show quick convergence with an error of few centimeters in the estimated position of the ship model. The proposed technique has application in the real field scenario by replacing the ultrasonic sensor with industrial grade long range acoustic modem. As compared with the existing systems such as LBL, SBL, USBL and others localization techniques, the proposed technique can save deployment cost and also cut the cost on number of acoustic modems involved.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.6
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• pp.405-411
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• 2017

As the number of sensors in a ship has increased, studies have been actively conducted to efficiently manage a large amount of data. Sensors in a ship follow the NMEA (National Marine Electronics Association) data format. In particular, NMEA0183 standardized as IEC 61162-1 and NMEA2000 standardized as IEC 61162-3 are widely used. NMEA0183 is a protocol based on serial communication and NMEA2000 is a protocol based on CAN (Controller Area Network) communication. We implemented a gateway that receives data from NMEA0183 sensors and NMEA2000 sensors and then transmits them to the server on TCP/IP network. By using the NMEA2000 0183/2000 gateway to receive the sensor data and manage it through the ship's preventive maintenance system, the sensor data can be utilized efficiently and promptly. This management can reduce crew's daily tasks and reduce the number of accidents.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.891-898
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• 2017

Climate changes consistently cause coastal accidents such as coastal flooding, so the studies on monitoring the marine environments are progressing to prevent and reduce the damage from coastal accidents. In this paper, we propose a new method to estimate the sea level which can be applied to the tidal sensors to monitor the variation of sea level. Existing sea level models are very complicated and need a lot of tidal data, so they are not proper for tidal sensors. On the other hand, the proposed algorithm is very simple but precise since we use the measured data from the sensor to estimate the sea level value in short period such as one or two hours. It is shown by experimental results that the proposed method is simple but predicts the sea level accurately.

• The Journal of Korea Robotics Society
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• v.10 no.1
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• pp.1-8
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• 2015

This paper proposes a study for accurate surface localization system using DWT(Discrete Wavelet Transform) and GPS/INS fusion algorithm. Because the propagation in the underwater is not passed by characteristics of the medium unlike the ground, the sonar system like DVL is used instead of GPS. But since these systems are installed on the seafloor and operated, a long time is required for installation and navigation systems are limited outside of the range area. And it is difficult to estimate position in a three-dimensional considering the depth in actual marine environment. In this paper, before the development of underwater localization system, precisely estimated position system is proposed in a two-dimensional by developing surface localization system using removing noise and disturbance with DWT and relatively inexpensive GPS and INS sensor.

• Journal of Ocean Engineering and Technology
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• v.24 no.4
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• pp.86-93
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• 2010

RFID has been used as an identification tool that substitutes for bar codes. Its areas of application are increasing due to its suitability in ubiquitous environment. In this paper, first, we review various aspects of RFID, including standards, characteristics, and relationships with wireless sensor networks. Then, we review the technical aspects of RFID and its areas of application, e.g., supply chain management (SCM) and manufacturing since 2005. SCM, in which RFIDs can shorten lead time and ensure the quality of products, is one of the most active application areas. Manufacturing is a relatively new area for RFID applications, but it is believed that it can enhance the productivity and the reliability of the products. Also, the authors suggest research issues and limitations of RFID, as well as possible application areas related to marine engineering.

• Journal of Ocean Engineering and Technology
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• v.24 no.4
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• pp.72-77
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• 2010

This paper presents a method for measuring the shaft power of a marine main engine. Usually, in traditional systems for measuring shaft power, a strain gauge is used even though it has several disadvantages. First, it is difficult to set up the strain gauge on the shaft and acquire the correct signal for analysis. Second, it is very expensive and complicated. For these reasons, we investigated alternative approaches for measuring shaft power and proposed a new method that uses a vision-based measurement system. For this study, templates for image processing and CCD cameras were installed at the both ends of the shaft. Then, in order for the cameras to capture the images synchronously, we used a trigger mark and a optical sensor. The position of each template between the first and the second camera images were compared to calculate the torsion angle. The proposed measurement system can be installed more easily than traditional measurement systems and is suitable for any shaft because it does not contact the shaft. With this approach, it is possible to measure the shaft power while a ship is operating.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.9
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• pp.797-804
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• 2013

In this paper, a study of a new hovering six dof underwater robot with redundant horizontal thrusters, titled HAUV (hovering AUV), is presented. The results of study on the structure design, deployment of thrusters, and development of the developed control system of the AUV was presented. For the HAUV structure, a structure design and an analysis of the thrusting system was performed. For navigation, a sensor fusion board which can proceed various sensor signals to identify correct positions and speeds was developed and a total control system including EKF (Extended Kalman Filter) was designed. Rolling, pitching and depth control tests of the HAUV have been performed, and relatively small angle error and depth tracking error results were shown.

• Journal of the korean society of oceanography
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• v.34 no.4
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• pp.200-206
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• 1999

Seawater sampling is the primary task for the study of the marine environmental parameters that require shipboard or laboratory experiments for their analyses, and is also required for the calibration of some instruments for in situ measurement. A new automatic bottle (AUTTLE) is developed for seawater sampling at any desired time and water depth by self-triggering. Both any type of single or assembled mooring for 15 days and manual actuation by using a remote messenger as existing instantaneous single point water samplers are possible. Its sampling capacity and the resolution of time setting are 2 liters and 1 second, respectively. The result of a field experiment with an optical backscattering sensor (OBS) and a total of 14 AUTTLES for the in situ calibration of the OBS shows that the AUTTLE must improve our understanding on the behavior of the sand/mud mixtures in the environments with high waves and strong tides. The AUTTLE will serve as a valuable instrument in the various fields of oceanography, especially where synchronized seawater sampling at several sites is required and/or the information in storm period is important.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.931-936
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• 2018

We designed an x-band radar for motion detector using a frequency tunable hairpin ring resonator. The proposed doppler radar sensor can vary the oscillation frequency by applying a hairpin resonator using a varactor diode to the oscillator, and this can also reduce the size by transmitting and receiving a signal from Tx/Rx dual antenna. The fabricated doppler radar sensor was fabricated in $30{\times}24mm$, and it was confirmed that the pulse width difference occurred according to the distance from the object. The measurement results showed oscillation at 10.525GHz. We confirmed that it is enough to use as radar for motion detection from the measured results.