• 제어로봇시스템학회논문지
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• 제19권2호
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• pp.95-101
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• 2013

The paper investigates the geometric effect of landmarks to the navigation error in the landmark based 3D vision navigation and introduces the INS/Vision integrated navigation system considering its effect. The integrated system uses the vision navigation results taking into account the dilution of precision for landmark geometry. Also, the integrated system helps the vision navigation to consider it. An indirect filter with feedback structure is designed, in which the position and the attitude errors are measurements of the filter. Performance of the integrated system is evaluated through the computer simulations. Simulation results show that the proposed algorithm works well and that better performance can be expected when the error characteristics of vision navigation are considered.

• Journal of Positioning, Navigation, and Timing
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• 제6권2호
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• pp.59-70
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• 2017

Since GPS signals are vulnerable to interference and obstruction, many alternate aiding systems have been proposed to integrate with an inertial navigation system. Among these alternate systems, the vision-aided method has become more attractive due to its benefits in weight, cost and power consumption. This paper proposes a loosely-coupled vision/INS integrated navigation method which can work in GPS-denied environments. The proposed method improves the navigation accuracy by correcting INS navigation and sensor errors using position and attitude outputs of a landmark based vision navigation system. Furthermore, it has advantage to provide redundant navigation output regardless of INS output. Computer simulations and the van tests have been carried out in order to show validity of the proposed method. The results show that the proposed method works well and gives reliable navigation outputs with better performance.

• 제어로봇시스템학회논문지
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• 제16권8호
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• pp.810-815
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• 2010

This paper proposes a vision/DR integrated navigation system using distance between wheels of the vehicle and a gyroscope. In order to show the validity of the proposed vision/DR integrated navigation system, experiments were performed for a trajectory of a mobile robot. Experimental results show that the proposed vision/DR integrated navigation system gives better navigation performance than a vision/DR integrated navigation system using only distance between wheels of the vehicle.

• 한국항공우주학회지
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• 제45권8호
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• pp.671-677
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• 2017

본 논문은 관성항법시스템(Inertial Navigation System)과 비전 센서(Vision Sensor)를 활용한 통합 항법시스템의 성능 향상을 위한 INS/멀티비전 통합항법 시스템을 제시하였다. 기존의 단일 센서나 스테레오 비전(Stereo vision)을 활용한 경우 측정되는 랜드마크의 수가 적을 경우 필터가 발산하는 문제가 발생할 수 있다. 이러한 문제를 해결하기 위해 본 논문에서는 3개의 비전 센서를 동체를 기준으로 $0^{\circ}$, $120^{\circ}$, $-120^{\circ}$으로 설치하여 단일 센서로 사용되는 경우보다 성능이 향상됨을 수치 시뮬레이션을 통하여 검증하였다.

• 전기학회논문지
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• 제63권1호
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• pp.123-131
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• 2014

An INS/vision integrated navigation algorithm is proposed for environments with insufficient number of landmarks. In the proposed algorithm, the raw measurements on the focal plane are directly used in order to cope with the situation where the number of landmarks are not sufficient. In addition to this, the combination of landmarks, which has smallest value of DOP, is used in the update of measurement in order to improve navigation performance. In order to evaluate the performance of the proposed integrated navigation system, Monte-Carlo simulation and van test was performed. The results of the simulation and experiment show that the proposed navigation system gives better navigation performance than an INS/vision integrated navigation system which does not use the raw measurements on the focal plane and the navigation system provides navigation solutions even in environments with insufficient number of landmarks.

• 전기학회논문지
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• 제59권11호
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• pp.2048-2057
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• 2010

Is this paper, a pedestrian inertial navigation system with vision is proposed. The navigation system using inertial sensors has problems that it is difficult to determine the initial position and the position error increases over time. To solve these problems, a vision system in addition to an inertial navigation system is used, where a camera is attached to a pedestrian. Landmarks are installed to known positions so that the position and orientation of a camera can be computed once a camera views the landmark. Using this position information, estimation errors in the inertial navigation system is compensated.

• 제어로봇시스템학회논문지
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• 제14권8호
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• pp.745-751
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• 2008

This paper presents a framework for GPS/INS/Vision based navigation system of helicopters. GPS/INS coupled algorithm has weak points such as GPS blockage and jamming, while the helicopter is a speedy and high dynamical vehicle amenable to lose the GPS signal. In case of the vision sensor, it is not affected by signal jamming and also navigation error is not accumulated. So, we have implemented an GPS/INS/Vision aided navigation system providing the robust localization suitable for helicopters operating in various environments. The core algorithm is the vision based simultaneous localization and mapping (SLAM) technique. For the verification of the SLAM algorithm, we performed flight tests. From the tests, we confirm the developed system is robust enough under the GPS blockage. The system design, software algorithm, and flight test results are described.

• International Journal of Aeronautical and Space Sciences
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• 제15권3호
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• pp.258-266
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• 2014

We present a system for the real-time visual relative navigation of a fixed-wing unmanned aerial vehicle in a GPS-denied environment. An extended Kalman filter is used to construct a vision-aided navigation system by fusing the image processing results with barometer and inertial sensor measurements. Using a mean-shift object tracking algorithm, an onboard vision system provides pixel measurements to the navigation filter. The filter is slightly modified to deal with delayed measurements from the vision system. The image processing algorithm and the navigation filter are verified by flight tests. The results show that the proposed aerial system is able to maintain circling around a target without using GPS data.

• 전기학회논문지
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• 제61권3호
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• pp.479-484
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• 2012

Geometric effect of landmarks to the navigation error is investigated in the two-dimensional line-of-sight measurement based vision navigation system. DOP is derived between line-of-sight measurement error and navigation solution error. For cases of three landmarks in an area, variations of the DOP were observed through computer simulations. Vision navigation system experiments were performed for the cases. Simulation and experimental results show that navigation solution errors have similar trend to DOP values of the simulation.

• 대한전자공학회논문지TC
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• 제48권10호
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• pp.20-28
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• 2011

이 논문은 위성항법시스템의 문제점인 위치오차와 실외음영지역을 해소하기 위하여 위성항법시스템과 비전시스템을 융합한 신뢰성있는 고정밀 측위 기술을 제안하였다. 동적단독측위에서 이동체는 이동 위치에 따라 사용할 수 있는 위성항법시스템의 수가 변화한다, 위치 측위를 위해서는 최소 4개 이상의 위성항법시스템으로부터 위치정보데이터를 수신 받아야 한다. 그러나 도심지역에서는 고층건물이나 장애물 또는 반사파에 의해 정확한 위치측위가 어렵다. 이러한 문제점을 해결하기 위하여 비전 시스템을 이용하였다. 위성항법시스템을 사용하기 열악한 도심지역의 특정 건물에 정확한 위치값을 결정해 놓는다. 그리고 비전시스템을 통해 특정 건물을 인식하고, 인식된 건물을 이용하여 위치오차를 보정해 준다. 이동체는 이동하면서 비전시스템을 이용하여 특정 건물을 인식하며 위치 데이터값을 만들어내고, 위치계산을 수정하여 안정되고 신뢰성있는 고정밀 위치측위를 할 수 있다.