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Development of Real-time Mission Monitoring for the Korea Augmentation Satellite System
Daehee Won,Koontack Kim,Eunsung Lee,Jungja Kim,Youngjae Song 사단법인 항법시스템학회 2023 Journal of Positioning, Navigation, and Timing Vol.12 No.1
Korea Augmentation Satellite System (KASS) is a satellite-based augmentation system (SBAS) that provides approach procedure with vertical guidance-I (APV-I) level corrections and integrity information to Korea territory. KASS is used to monitor navigation performance in real-time, and this paper introduces the design, implementation, and verification process of mission monitoring (MIMO) in KASS. MIMO was developed in compliance with the Minimum Operational Performance Standards of the Radio Technical Commission for Aeronautics for Global Positioning System (GPS)/SBAS airborne equipment. In this study, the MIMO system was verified by comparing and analyzing the outputs of reference tools. Additionally, the definition and derivation method of accuracy, integrity, continuity, and availability subject to MIMO were examined. The internal and external interfaces and functions were then designed and implemented. The GPS data pre-processing was minimized during the implementation to evaluate the navigation performance experienced by general users. Subsequently, tests and verification methods were used to compare the obtained results based on reference tools. The test was performed using the KASS dataset, which included GPS and SBAS observations. The decoding performance of the developed MIMO was identical to that of the reference tools. Additionally, the navigation performance was verified by confirming the similarity in trends. As MIMO is a component of KASS used for real-time monitoring of the navigation performance of SBAS, the KASS operator can identify whether an abnormality exists in the navigation performance in real-time. Moreover, the preliminary identification of the abnormal point during the post-processing of data can improve operational efficiency.
Won, Daehee,Kim, Wonhee,Tomizuka, Masayoshi IEEE 2017 IEEE/ASME transactions on mechatronics Vol.22 No.6
<P>Although previous control methods improve control performance in electrohydraulic servo system (EHSS), they require full-state feedback information and/or the derivative of the measured signals so that noise may be amplified. In this paper, we propose a high-gain-observer-based integral sliding mode control to improve the position tracking performance of the EHSSs while solving the previous problems. The proposed method consists of a high-gain observer and an integral sliding mode controller. The high-gain observer is designed to estimate the velocity and load pressure using the position feedback. The stability is proven without the approximation of the model in EHSS. The integral sliding mode controller is proposed to improve the position tracking performance using the flatness property of the system. In the controller, the required derivatives of the state variables are obtained using the flatness property without employing the derivative of the measured signal.</P>
Won, Daehee,Ahn, Jongsun,Sung, Sangkyung,Heo, Moonbeom,Im, Sung-Hyuck,Lee, Young Jae Hindawi Limited 2015 Journal of sensors Vol.2015 No.-
<P>A navigation algorithm is proposed to increase the inertial navigation performance of a ground vehicle using magnetic measurements and dynamic constraints. The navigation solutions are estimated based on inertial measurements such as acceleration and angular velocity measurements. To improve the inertial navigation performance, a three-axis magnetometer is used to provide the heading angle, and nonholonomic constraints (NHCs) are introduced to increase the correlation between the velocity and the attitude equation. The NHCs provide a velocity feedback to the attitude, which makes the navigation solution more robust. Additionally, an acceleration-based roll and pitch estimation is applied to decrease the drift when the acceleration is within certain boundaries. The magnetometer and NHCs are combined with an extended Kalman filter. An experimental test was conducted to verify the proposed method, and a comprehensive analysis of the performance in terms of the position, velocity, and attitude showed that the navigation performance could be improved by using the magnetometer and NHCs. Moreover, the proposed method could improve the estimation performance for the position, velocity, and attitude without any additional hardware except an inertial sensor and magnetometer. Therefore, this method would be effective for ground vehicles, indoor navigation, mobile robots, vehicle navigation in urban canyons, or navigation in any global navigation satellite system-denied environment.</P>
Development of Ground Monitoring and Control System for Korea Augmentation Satellite System
Daehee Won,Chulhee Choi,Eunsung Lee,Hantae Cho,Dongik Jang,Eunok Jang,Heetaek Lim,Ho Sung Lee,Jungja Kim,Joohap Choi 사단법인 항법시스템학회 2023 Journal of Positioning, Navigation, and Timing Vol.12 No.2
The Korea Augmentation Satellite System (KASS) is the first satellite navigation enhancement system in Korea developed in compliance with international standards. Technologies accumulated during the development process should be spread to industries such as academia and serve as the basis for developing the domestic satellite navigation field. This paper introduces the development process from design to implementation, testing, and verification of KASS control systems (KCS). First, development standards, milestones, requirements, and interface standards are presented as KCS development methods, and major functional design, physical design, and hardware/software implementation are described based on the allocated requirements. Subsequently, the verification environment, procedures, and results of the development product are covered and the developed operational and maintenance procedures are described. In addition, based on the experience gained through the development, suggestions were made for beneficial technology development and organization when promoting satellite navigation projects in the future. Since this work has important historical value for the development of domestic satellite navigation, it is expected that the development results will be shared with academia and industry in the future and be used as basic data for similar development.
Navigation Performance Analysis of KASS Test Signals
Daehee Won,Eunsung Lee,Chulhee Choi 사단법인 항법시스템학회 2023 Journal of Positioning, Navigation, and Timing Vol.12 No.4
This paper presents the analysis results of navigation performance of Korea Augmentation Satellite System (KASS) test signals. Performance analysis was performed with Global Positioning System (GPS) and Satellite Based Augmentation System (SBAS) signals received from 7 KASS reference stations. And the performances were analyzed in terms of the signal strength, statistics for each SBAS message, coverage of ionospheric correction, accuracy, integrity, continuity, and availability. In addition, the navigation solutions provided by commercial receiver was analyzed and the performance experienced by general users was presented. Lastly, directions for further improvement of the KASS system were addressed. These performance analysis results can be used to confirm the feasibility of utilizing KASS in user applications.