• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.7
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• pp.664-672
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• 2010

This paper provides the target observability analysis of time-to-go polynomial guidance law with bearing-only measurement. In this study, a direct approach is used to analyze the target observability. Since the observability condition of a constant-velocity target is given by the function of LOS angle only, the target observability characteristic is determined by substituting the closed form solution of LOS angle to the observability condition directly. The analysis results show that the target observability is depended on the choice of guidance gain, initial intercept condition and guidance command shape. After that this mathematical analysis result is evaluated and demonstrated by number of simulation.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.421-422
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• 2007

계통의 정확한 상태추정을 위해서는 현재 확보된 데이터를 이용하여 계통의 가관측성을 확인하여야 한다. 실제 계통에서는 통신장애, 계기의 고장 등과 같은 이유로 전체 계통에 대한 상태추정이 불가능한 경우가 있으며, 이러한 경우 계통은 가관측성을 확보하지 못하였다고 한다. 견실한 상태추정을 위해서는, 전체 계통의 가관측성을 확보하였는지 판단하고, island가 발생한 경우 의사측정데이터를 추가하여 계통의 가관측성을 확보하는 과정이 필요하다. 본 논문에서는 수치해석법을 이용한 가관측성 해석 알고리즘을 이용하여 전체 시스템의 가관측성을 판별하고, 필요한 경우 의사측정데이터를 추가하는 프로그램을 개발하였다. IEEE 14모선 시험계통을 이용하여 가관측성 확보에 대한 타당성을 검증하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.3
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• pp.236-242
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• 2010

A GNSS/INS integration system can not provide navigation solutions if there are no available satellites. To overcome this problem, a vision sensor is integrated with this system. Since generally a vision aided integration system uses only feature point to compute navigation solutions, it has a problem in observability. In this case, additional landmarks, which is priory known points, can improve the observability. In this paper, the observability is evaluated using TOM/SOM matrix and Eigenvalues. There are always the observability problems in the feature-point-only case, but the landmark-use case is fully observable after the $2^{nd}$ update time. Consequently the landmarks ensure full observability, so the system performance can be improved.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.276-284
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• 2013

This paper considers the transfer alignment in the inertial navigation system and the observability analysis is performed for velocity matching. The state variable of the Kalman filter is modeled including the lever arm error and the measurement equation is obtained. The SOM(Stripped Observability Matrix) method is used for the observability analysis for various maneuvering conditions of the vehicle, which gives the full state observability condition as a specific maneuver sequence of the vehicle. While the observability analysis of a lever arm effect in the existing papers is mainly performed by simulations, we performed it analytically by the observability analysis method. The analysis result is verified using the computer simulations.

• The Journal of the Acoustical Society of Korea
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• v.18 no.6
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• pp.9-16
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• 1999

As a part of target motion analysis(TMA) with highly noisy bearings-only measurements from a passive sonar system, a nonlinear batch estimator is proposed to provide the initial estimates to a sequential estimator called the modified gain extended Kalman filter(MGEKF). Based on the system observability analysis of passive target tracking, a practical and effective method is suggested to determine the observer maneuvers for improved TMA performance through system observability enhancing. Also suggested is a method to determine observer location for enhanced system observability at the initial phase of TMA from various engagement boundaries which represent the relationship between observer-target relative geometrical data and system observability. The proposed TMA methods are tested by a series of computer simulation runs.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.443-446
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• 2006

INS를 사용하는 지상항법시스템은 GPS 등의 보조 센서와 관계없이 다양한 환경에서 장시간 운용시 항법 성능을 보장하기 위하여 재교정 과정을 거쳐야 한다. 본 논문에서는 이러한 재교정 절차 없이 장시간의 반복적인 사용에도 신뢰할 수 있는 항법해를 제공하기 위한 동작간 교정 기법에 대한 기초 연구를 수행한다. 이를 위하여 지상항법시스템에 나타나는 다양한 운동 특성을 묘사할 수 있는 시뮬레이터를 개발하고, 각 운동 특성에서의 가관측성 해석과 INS와 GPS의 항법 출력 특성을 분석한다.

• Journal of Advanced Navigation Technology
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• v.22 no.3
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• pp.220-227
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• 2018

The most widely used method for constructing an inertial navigation system (INS)/global navigation satellite system (GNSS) coupling system is to construct an integrated navigation system using a Kalman filter. However, depending on the trajectory, non-observable state variables may be generated. In this case, the state variables are not estimated. To solve this problem, a integrated navigation system is constructed and then an observability analysis is performed. In this paper, a 24th order position-matched Kalman filter is defined to design an INS/GNSS integrated navigation system for vehicles moving with a large pitch angle change. To verify the appropriateness of the error state variables applied to the Kalman filter, an observability analysis was performed. The trajectory was divided into five segments, and the piece-wise constant system (PWCS) was assumed for each segment, and the results were analytically analyzed. The analytical results and the simulation results confirm that the error state parameters of the Kalman filter are well-designed to the estimation side.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.258-260
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• 2008

전력계통 규모가 대형화, 복잡화됨에 따라 전력계통의 안정적 운용과 양질의 전력공급을 보장하기 위해 EMS(Energy Management System)를 사용, 에너지 시스템 운용에 있어 안정적, 효과적 제어를 기하고 있다. 그러나 전력감시제어설비(SCADA)로부터의 실시간 데이터 누락, 또는 측정데이터의 오류가 발생할 경우 시스템상의 가관측성이 확보되지 않게 되어 상태추정이 불가능 할 수 있다. 이에 상태추정의 가관측성을 제공하기 위해 현재 한국형 EMS (K-EMS : Korea Energy Management System)의 응용프로그램 중 하나인 BLF(Bus Load distribution Factor) 산정 프로그램을 개발중에 있으며, 본 논문에서는 BLF 산정 프로그램을 통한 가관측성 확보방안과 프로그램에 대한 알고리즘에 대해 설명하고자 한다.

• 전기의세계
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• v.44 no.10
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• pp.40-46
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• 1995

소음을 줄이고자 하는 위치 혹은 공간의 선정문제, 또한 제어용 음파가 원래 제어하고자 하는 음파와 함께 섞인 상태에서 관찰하게 됨으로서 발생하는 문제, 제어용 음원의 위치 선정에 관련된 사항 등 가관측성 및 가제어성으로 대별될 수 있는 부분과 제어대상 물리량, 즉 제어대상 가격함수 선정의 물리적 적합성 등이 있을 수 있다. 전술한 가관측성 및 가제어성 관련 사항은 참고문허[3]에 비교적 상세히 기술되어 있으므로 본 고에서는 제어대상 가격함수의 선정과 관련된 음향학적 사실들을 중점적으로 다루도록 한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.1
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• pp.16-24
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• 2011

In this paper, we propose a new guidance law for target observability enhancement, which can control both terminal impact angle and acceleration. The proposed guidance law is simple form, combined conventional time-to-go polynomial guidance and a additional bias term which consists of relative position and proportional gain. The guidance law provides oscillatory flight trajectory and it maintains the conventional time-to-go polynomial guidance performance. To investigate the characteristics of the guidance law, we derive the closed-form solution, and various simulations are performed for proving the validity of the proposed guidance.