• 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.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.209-215
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• 2019

The purpose of this study is to suggest the development of interactive services and technologies in the media industry. Through the analysis of domestic two-way broadcasting contents service, this study analyzed platform and services type according to service type of terrestrial broadcasting, SO operator and Telco. Also, by identifying the characteristics of interactive programs(open, interactive, personalized, stereoscopic), this study propose important convergence possibilities of the future providers and development plans through supporting technologies and services for each characteristic. In the case of terrestrial broadcasters, ARS, web sites and mobile apps were mostly provided in both directions, and SO and satellite broadcasting operators were found to provide diversity in interactive service operation using data domain. In the case of IPTV companies, most of them provide interactive services with additional video or information service through adjustment button or app, and cable TV operators had more adjustment data broadcasting than exclusive use data broadcasts. Therefore, domestic interactive broadcasting service type needs convergence type of revenue model needs and needs to be converted into new competitive interactive broadcasting program service environment.

• Journal of Advanced Navigation Technology
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• v.22 no.6
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• pp.577-584
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• 2018

GNSS based transport infrastructure cluster is to broadcast satellite navigation correction information and integrity information capable of precise positioning for land transport users. This makes it possible to do lane-level positioning reliably. However, in order to provide the lane-level positioning and correction information service nationwide, new station sites selection and to build GNSS stations have a heavy cost and a burden for a considerable period of time. In this paper, we propose the cluster design criteria and national-wide network-based precise positioning for land transportation (NETPPI-LT) cluster design for a cluster-based precise positioning. Furthermore, it is analyzed the precise positioning pre-performance of this cluster design based on the spatial error and verified its suitability as the precise positioning pre-performance of the cluster design.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.882-885
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• 2014

The duration and frequency of flooding and not last long, by the time climate change drought. The increased accordingly by reducing stream flow and year variation. This trend is expected to continue, and change towards a comprehensive analysis of such quantity, quality and management of water resources are managed. Flood warning system is called to perform them electronically to the management of water resources such as these to be in the organic water-related basic data acquisition, storage, processing and utilization. Can be divided into hydrological observations and flood warning systems alert system broadcast system. Hydrological observation system is the measurement from the hydrological stations (water level, rainfall, water) that can be observed hydrological status of the dam basin hydrological observation data transmitted to the central office, located at the dam monitoring and control system through a variety of networks including satellite, and the collected defined as the system that sent the K-water head office in 1 minute increments hydrological observation data. Headquartered in support of this decision. Dimensions of the dam are provided in addition to inward. Channeled through various hydrologic analysis and leveraging the data transfer. This paper looks at ways to build out hydrological observation system.

• Journal of Navigation and Port Research
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• v.38 no.4
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• pp.373-378
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• 2014

In order to prepare for recapitalization of differential GNSS (DGNSS) reference station and integrity monitor (RSIM) due to GNSS diversification, this paper focuses on differential correction algorithm using GPS/Galileo pesudorange. The technical standards on operation and broadcast of DGNSS RSIM are described as operation of differential GPS (DGPS) RSIM for conversion of DGNSS RSIM. Usually, in order to get the differential corrections of GNSS pesudorange, the system must know the real positions of satellites and user. Therefore, for calculating the position of Galileo satellites correctly, using the equation for calculating the SV position in Galileo ICD (Interface Control Document), it estimates the SV position based on Ephemeris data obtained from user receiver, and calculates the clock offset of satellite and user receiver, system time offset between GPS and Galileo, then determines the pseudorange corrections of GPS/Galileo. Based on a platform for performance verification connected with GPS/Galileo integrated signal simulator, it compared the PRC (pseudorange correction) errors of GPS and Galileo, analyzed the position errors of DGPS, DGalileo, and DGPS/DGalileo respectively. The proposed method was evaluated according to PRC errors and position accuracy at the simulation platform. When using the DGPS/DGalileo corrections, this paper could confirm that the results met the performance requirements of the RTCM.

• Journal of Korea Technology Innovation Society
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• v.10 no.1
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• pp.164-181
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• 2007

This paper empirically analyzes determinants of DTV (Digital Television) adoption in household survey data with IT-related household demand characteristics. To this purpose, we conducted a survey for the adoption of DTV to 1,000 households nationwide. In the questionnaire, various questions asking socio-economics characteristics such as age, education, income were included. Also, status of adoption and usage of IT services such as paid broadcasting, internet, and DVD were asked. To analyze the determinants of intention of purchasing, decision of purchasing, and the timing of purchasing DTV, we adopted the ordered logit, binary logit and multinomial legit models. When there is an order among groups, ordered logit was employed and when there is no orders among groups, multinomial logit was emplyed for the estimation. It is found that when conditions of other explanatory variable are constant, the more educated household heads are, the more probable they become early adopters of DTV. It is also found that other conditions being constant, the income level of households and IT-related household demand characteristics are very important factors affecting DTV adoption. Since the likelihood of purchasing DTV is much higher for those who know the government policy of analog broadcasting termination schedule than others who do not know, dissemination of the Korean government's digital broadcasting policy will affect significantly the adoption of DTV. And policy with various incentives ought to be employed to accelerate DTV adoption, because households with the older TV sets are more likely to purchase DTV. It is suggested that the Korean government should develop policy to connect both DBS (Direct Broadcast Satellite) and DTV since DBS subscribers are more likely to be an early adopter than non-subscribers.

• Journal of Distribution Science
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• v.6 no.1
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• pp.47-62
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• 2008

Joining the WTO in 2001, China became a number of the global economic system. China succeeded in vying to host Beijing 2008 Olympic Games and World Expo 2010 Shanghai. It is China's honor and opportunity to have high economic growth in the coming future. In 2007, the total cost of public logistics decreased by 18.2% than 2006 to 4540.6 billion RMB, accounting for 18.4% of the GDP. So, China logistics is a huge industry and a growing market full of charm. The statistic ratios of China's logistics and growth trends show us it is an important issue to build and run an effective logistics system. However, research on China's logistics systems and supply chain is lacked. This study is focus on the logistic location strategy in China including the study of factories and warehouses geographic strategy concerned with SCM. The core of this study is to propose a New Multi-Facilities Location Decision Model. This study banded the revised gravity center, the standard single facility location decision model(Gravity Center Model) and the transportation model into a new Multi-Facilities Location Decision Model. In addition, this study suggested the gravity center of population, the gravity center of each industry, the location decision graded-list of each industry of china using the gravity center model and the revised gravity center model. The new Multi-Facilities Location Decision Model proposed in this study can be used to solve the location decision problem of more than two facilities. And it can be used in the fields such as the location decision of production facility and service facility, the location of distribution and logistics, the location of broadcast and satellite communications, the location of wireless communication tower and so on.

• Journal of Cadastre & Land InformatiX
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• v.50 no.1
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• pp.107-123
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• 2020

With stabilization of the recent multi-GNSS infrastructure, and as multi-GNSS has been proven to be effective in improving the accuracy of the positioning performance in various industrial sectors. In this study, in view that SF(Single frequency) GNSS receivers are widely used due to the low costs, evaluate effectiveness of SF Real Time Point Positioning(SF-RT-PP) based on four multi-GNSS surveying methods with RTCM-SSR correction streams in static and kinematic modes, and also derive response challenges. Results of applying SSR correction streams, CNES presented good results compared to other SSR streams in 2D coordinate. Looking at the results of the SF-RT-PP surveying using SF signals from multi-GNSS, were able to identify the common cause of large deviations in the altitude components, as well as confirm the importance of signal bias correction according to combinations of different types of satellite signals and ionospheric delay compensation algorithm using undifferenced and uncombined observations. In addition, confirmed that the improvement of the infrastructure of Multi-GNSS allows SF-RT-SPP surveying with only one of the four GNSS satellites. In particular, in the case of code-based SF-RT-SPP measurements using SF signals from GPS satellites only, the difference in the application effect between broadcast ephemeris and SSR correction for satellite orbits/clocks was small, but in the case of ionospheric delay compensation, the use of SBAS correction information provided more than twice the accuracy compared to result of the Klobuchar model. With GPS and GLONASS, both the BDS and GALILEO constellations will be fully deployed in the end of 2020, and the greater benefits from the multi-GNSS integration can be expected. Specially, If RT-ionospheric correction services reflecting regional characteristics and SSR correction information reflecting atmospheric characteristics are carried out in real-time, expected that the utilization of SF-RT-PPP survey technology by multi-GNSS and various demands will be created in various industrial sectors.