• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.11
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• pp.947-957
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• 2014

In this paper, the navigation performance analysis techniques of a pseudolite navigation system are proposed. To validate the techniques, operation and navigation test results using real test data are addressed. The conventional navigation performance analysis methods used for satellite navigation system, such as Galileo and GPS, are analyzed to identify the error factor and to check the criterion of UERE defined in the standard document. And then the method to calculate the UERE through the ranging measurements are studied. By identifying the error factor in pseudolite navigation system based on these methods, the available UERE observation and calculation method applicable to pseudolite navigation are proposed. Simulation results considering various circumstances and the actual flight test results are presented to verify the proposed method.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.2
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• pp.463-472
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• 2018

The aim of this pilot survey was to investigate the presence status, usage problems, and improvement needs of the upper extremity rehabilitation equipment(: UERE) in the department of occupational therapy(: OT) of hospital setting in Korea. The authors received a questionnaires of clinicians working in a department of OT hospital setting through a social network service. Responses of 72 were analyzed in the first questionnaire, and 47 were analyzed in the second questionnaire. In the first questionnaire, the presence status of 16 UERE was confirmed to be 29.2~97.2%, and the usage experience of 9 UERE in the second questionnaire was 36.2~97.9%. In the second questionnaire, UERE's usage problems were reported discomfort in 15(31.9%) of 47 therapists, and improvement needs were 23(49%). The usage problems of the 9 UERE questioned by open-ended questionnaire were uninteresting, easily damaged, level unadjustable, direction unadjustable, and inconvenient installation. The improvement needs were classified into digitization, durability, level adjustable, adjustable function, convenience. The present pilot survey identified the presence status and usage experience of UERE in the department of OT and could be used as a basis for the development of closed-ended questionnaire on usage problems and improvement needs of UERE.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1342-1347
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• 1997

In this paper, we performed simulations of aircraft automatic landing using GPS, DGPS and CDGPS. Our purpose is examining the possibility of aircraft landing using GPS through the simulation results. The aircraft landing is composed of two stages, glide-slope and flare. Therefore, LQG controllers are designed separately. In simulations, measurement noise depends not only on UERE and UERRE(which have different values in GPS, DGPS, and CDGPS) but also on DOPs. DOPs are determined only by the geometry of GPS satellite constellation. For DOP calculation, we also made program for GPS satellites orbit simulatiion. Accordin to the simulation results, ICAO CAT III can be achieved of CDGPS is used.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.467-470
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• 2006

본 논문에서는 GPS와 의사위성을 이용하는 무인항공기 착륙용 측위 정확도 예측 프로그램의 개발을 나타내었다. 무인항공기의 착륙 환경을 모사하기 위하여 착륙 장소의 GIS 데이터를 기반으로 광선추적(ray tracing) 기법을 이용하여 의사 위성신호의 전파과정을 상세히 모사하였으며, GPS 위성의 위치는 위성궤도 생성 프로그램과 오차 모델을 이용하여 생성하였다. 의사위성 신호와 GPS 신호를 동시에 사용하여 위치를 구할 수 있으며, 일반적인 GPS UERE 모델과 의사위성 설치 환경의 UERE 모델을 이용하여 DOP와 NSP를 계산하고 측위 정확도를 예측할 수 있다. 개발된 측위 정확도 예측 프로그램은 무인항공기의 착륙지의 선정 및 오차 예측뿐 아니라 의사위성과 GPS를 동시에 사용하는 모든 응용에 효과적으로 적용될 수 있다.