• Journal of Advanced Navigation Technology
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• v.16 no.4
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• pp.619-626
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• 2012

One-way Network-RTK(Real Time Kinematics) is considered as a method which can satisfy moving vehicle's recently-required high accuracy and mobility. When we use one-way Network RTK for vehicle navigation, multiple cells-based system is required to provide the service continuously in wide area. The rover which moves through various cells inevitably experiences a correction discontinuity, which is not eliminated by the DD(Double Difference) method and to cause 13cm(horizontal) and 48cm(vertical) position error. We suggest three solutions to reduce this discontinuity, which are identification of master RS with neighbor networks, duplication of communication module to receive corrections from other cells, and ambiguity adjustment between neighbor cells. All of our suggestions reduce the error to 1/4 wavelength in measurement and 3cm in position-domain, and we suggest the ambiguity adjustment is the best when we consider the extendibility of service area and the cost of rover device.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.545-554
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• 2017

Among various applications of the High Altitude Long Endurance (HALE) Unmanned Aerial Vehicle (UAV), this paper has a focus on the Global Positioning System (GPS) utilizing pseudolite and its improved performance, particularly during the multi-purpose missions. In a multi-purpose mission, the HALE UAV follows a specified flight trajectory for both navigation applications and missions. Some of the representative HALE missions are remote exploration, surveillance, reconnaissance, and communication relay. During these operations, the HALE UAV can also be an additional positioning signal source as it broadcast signals using pseudolite. The pseudolite signal can improve the availability, accuracy, and reliability of the GPS particularly in areas with poor signal reception, such as shadowed regions between tall buildings. The improvement in performance of navigation is validated through simulations of multi-purpose missions of the solar-powered HALE UAV in an urban canyon. The simulation includes UAV trajectory generation at stratosphere and uses actual geographical building data. The results indicate that the pseudolite-equipped HALE UAV has the potential to enhance the performance of the satellite navigation system in navigationally degraded regions even during multi-purpose operations.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.307-310
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• 2003

In the maritime container terminal, LMTT(Linear Motor-based Transfer Technology) is horizontal transfer system for the yard automation, which has been proposed to take the place of AGV(Automated Guided Vehicle). The system is based on PMLSM (Permanent Magnetic Linear Synchronous Motor) that is consists of stator modules on the rail and shuttle car (mover). Because of large variant of mover's weight by loading and unloading containers, the difference of each characteristic of stator modules, and a stator module's trouble etc., LMCPS (Linear Motor Conveyance Positioning System) is considered as that the system is changed its model suddenly and variously. In this paper, we will introduce the soft-computing method of a multi-step prediction control for LMCPS using DR-FNN (Dynamically-constructed Recurrent Fuzzy Neural Network). The proposed control system is used two networks for multi-step prediction. Consequently, the system has an ability to adapt for external disturbance, cogging force, force ripple, and sudden changes of itself.

• International Journal of Contents
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• v.9 no.4
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• pp.22-29
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• 2013

In this paper, we propose a integrated real-time monitoring system for recycling agriculture resourcing based on USN. We design and implement the monitoring system so that we can integrate the quality control of farmyard and liquid manures, barn environment monitoring, and positioning information control into a total management system performing recycling of excrement and manure. Selection of sensors and sensor-node construction and requirements, structure of wire/wireless communication networks, and design of monitoring program are also presented. As a result of operating our system, we can get over various drawbacks of conventional separated system and promote the proper circulation of excrement up to the farmyard. We confirm that these advanced effects arise from the effective management of the total system integrating quality control of farmyard/liquid manure, barn/farmhouse information, and vehicle moving monitoring information etc. Moreover, this monitoring system is able to exchange real-time information throughout communication networks so that we can construct a convenient information environment for agricultural community by converging IT technology with farm and stockbreeding industries. Finally we present some results of processing using our monitoring system. Sensing data and their graphs are processed in real-time, positioning information on the v-world map offers various moving paths of vehicles, and statistical analysis shows all the procedure from excrement occurrence to recycling and resourcing.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.2
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• pp.1-8
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• 2006

In this paper, an optimum design technology is developed to find an optimal position of the shock absorber using ADAMS and VisualDOC. A vehicle with a torsion-beam rear suspension is modeled by using ADAMS. Design variables for the optimal positioning of the shock absorber are defined considering the hard points of the chassis structure and design positioning are specified through the sensitivity analysis using a bump-crossing simulation. The objective function is defined as the joint reaction forces of the shock absorber connecting joints of the chassis structure. Sequential Quadratic Programming and Genetic Algorithms are used for this study. To validate the optimized design variables, pothole simulations are performed. GA showed better results than SQP algorithms for this design purpose.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.157-164
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• 2007

For a GPS antenna to normally receive GPS satellite signals during full flight mission of a satellite launch vehicle, it should be installed on skin of the vehicle. The surface of a launch vehicle is drastically heated up due to aerodynamic heating effect during flight, so that the GPS antenna mounted on surface of the launch vehicle is directly exposed to extremely hot temperature environment. Hot temperature test specification of the GPS antenna, therefore, is severer than inner components. This paper describes that procedures and results of performance analysis of the GPS antenna for KSLV-I under hot temperature environment. The GPS antenna was not deformed physically and inner LNA(Low Noise Amplifier) operated normally without performance degradation.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.2
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• pp.61-73
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• 2014

An automatic vehicle location tracing system is to build GIS server and on transmission for providing service in various ways by collecting a GPS location information from each vehicle. It is to save GPS data from OBU built-in on the vehicle and transmit the GPS data using the RSU on the roadside and WAVE communication technology. The collected data from the RSU is transmitted to the GIS server and stored in DB(database) and based on the GPS data that was collected from the each vehicle the system is to provide user service to suit the applications so it is to provide various services between RSU and OBU. In this paper, by implementing a multi-session process between the RM and the RMA a variety of services between RSU and OBU are provided. In addition, the system is designed and implemented using GPS to provide a variety of services, for the services provided from each RMA by configuring them as an independent session so it enables a variety of services implemented from one of RSU. With the result of the comparative analysis on the multi-session processing and single-session processing it shows that the differenes of them are minor in repect of the data loss rate and the data transfer rate but various services can be provided.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.2
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• pp.66-72
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• 2008

A distributed missile system is composed of command control center, radar and launcher which exchange information each other to use wire or wireless network. The distributed missile system is required mobility for operational convenience and survivability. Also missile system requests land navigation system to provide relatively accurate attitude. For reason of these requirements, each subsystem needs land navigation which provides information of position and attitude. This paper represents operational concept for land navigation to consider operational environment and concrete operational procedure to apply the operational concept. In state that there is no operation for land navigation of distributed missile system internally so for, this paper could be helped to establish operational concept and procedure of this kind of system.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.1
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• pp.48-54
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• 2017

A minimum turning circle test of vehicles is operated by using Real-Time Kinematic(RTK) surveying method which enhances the precision of the Global Positioning System(GPS). A procedure of the conventional method to obtain results is to take post processing after the test. Therefore, it is difficult to ensure results in an instant. This paper introduces developed process and equipment that can immediately obtain results after the minimum turning test without post processing.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.1
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• pp.49-58
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• 2003

Compared with generic GPS receiver, post-processing software GPS receiver has many advantages for high dynamic vehicle tracking. It has the advantage of the application of various tracking algorithms and aiding schemes. The post-processing system observes the carrier phase measurement data from the recorded GPS signals, detects and isolates the cycle slip. The observed carrier phase data and the raw data of the reference station are processed by carrier phase DGPS scheme. And the integer ambiguity resolution algorithm is used for resolving single frequency carrier phase ambiguity. The results of static and real flight test are presented and show that the proposed GPS translator processing system satisfies submeter accuracy.