This paper presents relative navigation using intermittent laser-based measurement data for spacecraft flying formation that consist of two spacecrafts; namely, chief and deputy spacecrafts. The measurement data consists of the relative distance measured by a femtosecond laser, and the relative angles between the two spacecrafts. The filtering algorithms used for the relative navigation are the extended Kalman filter (EKF), unscented Kalman filter (UKF), and least squares recursive filter (LSRF). Numerical simulations reveal that the relative navigation performances of the EKF- and UKF-based relative navigation algorithms decrease in accuracy as the measurement outage period increases. However, the relative navigation performance of the UKF-based algorithm is 95 % more accurate than that of the EKF-based algorithm when the measurement outage period is 80 sec. Although the relative navigation performance of the LSRF-based relative navigation algorithm is 94 % and 370 % less accurate than those of the EKF- and UKF-based navigation algorithms, respectively, when the measurement outage period is 5 sec; the navigation error varies within a range of 4 %, even though the measurement outage period is increased. The results of this study can be applied to the design of a relative navigation strategy using the developed algorithms with laser-based measurements for spacecraft formation flying.

In spite of a short history of only 30 years in space development, Korea has achieved outstanding space development capabilities, and became the 11th member of the “Space Club” in 2013 by launching its own satellites with its own launch vehicle from a local space center. With the successful development and operation of more than 10 earth-orbiting satellites since 1999, Korea is now rapidly expanding its own aspirations to outer space exploration. Unlike earth-orbiting missions, planetary missions are more demanding of well-rounded technological capabilities, specifically trajectory design, analysis, and navigation. Because of the importance of relevant technologies, the Korean astronautical society devoted significant efforts to secure these basic technologies from the early 2000s. This paper revisits the numerous efforts conducted to date, specifically regarding flight dynamics and navigation technology, to prepare for future upcoming planetary missions in Korea. However, sustained efforts are still required to realize such challenging planetary missions, and efforts to date will significantly advance the relevant Korean technological capabilities.

항로표지는 해상교통의 안전을 도모하는 선박운항의 능률성을 향상시키기 위한 해양교통안전시설로서 국제적으로 IALA에서 관련 규정 및 권고사항에 따라 적용하고 있다. 우리나라는 항로표지 이용자에게 안정적인 서비스를 제공하기 위해 항로표지를 관리하고 있지만 항로 표지사고는 연평균 141건이 발생하고 있다. 항로표지사고는 관리자에게 기능을 복구시켜야 비계획 업무를 강요하고, 이용자에게는 심리적 불안 감을 유발하여 경제적인 손실이 발생한다. 본 연구에서는 항로표지사고로 인해 기능정지에서 복구까지 소요되는 관리자의 경제활동과 이용자의 불편함을 비용으로 정량화하기 위한 항로표지사고의 사회적비용(Social Cost) 평가모델을 개발하였다. 항로표지사고의 사회적비용 평가모델은 생산손실비용, 행정비용, 위험비용의 합으로 제안하였다.

To fly a drone or unmanned aerial vechicle(UAV) safely, its pilot needs to maintain high situation awareness of its flight space. One of the important ways to improve the flight space awareness is to integrate both the global and the local navigation map a drone provides. However, the drone pilot often has to use the inconsistent reference frames or perspectives between the two maps. In specific, the global navigation map tends to display space information in the third-person perspective, whereas the local map tends to use the first-person perspective through the drone camera. This inconsistent perspective problem makes the pilot use mental rotation to align the different perspectives. In addition, integrating different dimensionalities (2D vs. 3D) of the two maps may aggravate the pilot’s cognitive load of mental rotation. Therefore, this study aims to investigate the relation between perspective difference (0°, 90°, 180°, 270°) and the map dimensionality matches (3D-3D vs. 3D-2D) to improve the way of integrating the two maps. The results show that the pilot’s flight space awareness improves when the perspective differences are smaller and also when the dimensionalities between the two maps are matched.

Common Maritime Data Structure (CMDS) is commonly used by shore and ship users in e-Navigation data domain. In the overarching of e-Navigation architecture, IHO uses S-1XX, a digital exchange standard for next-generation marine information, as data exchange standard. The current CMDS has the advantage of intuitively recognizing the overall structure of e-Navigation. However, it has disadvantage in that it does not allow stakeholders to easily understand benefits that e-Navigation can provide when implementing e-Navigation. In this study, the direction of improving existing system for effective e-Navigation implementation was proposed considering RCOs (Risk Control Options) with expected composition of ship/ shore/ communication system by sector.

러시아의 위성항법시스템인 GLONASS(GLObal NAvigation Satellite System)는 2011년 10월 이후 정상적으로 재가동되었으며 지속적으로 시스템 구성이 현대화되고 있다. 최근 2017년 10월 16일 발사된 GLONASS 752 위성(GLONASS-M)이 정상 작동됨에 따라서 2세 대 위성인 GLONASS-M 22기와 3세대 위성인 GLONASS-K 1기로 총 24기 위성이 구축되었다. 따라서 본 논문은 현재의 GLONASS 위성 항법시스템의 항법위성으로부터 실데이터를 수신하여 항법파라미터 특성 및 성능을 분석하고자 하였다. 수신된 데이터를 분석한 결과 항상 항법위성 5~11기가 동시에 가시선상에 있어서 항법신호를 수신할 수 있음을 확인하였으며, 실험에 이용된 위성들의 DOP(Dilution of Position)는 GDOP, PDOP, HDOP, VDOP, TDOP 각각 2.790, 2.424, 1.169, 2.123, 1.381을 얻었다. 또한 수신된 데이터의 위치 정밀도를 분석 한 결과 표준편차 1.4m로 매우 우수하였다. 결과적으로 GLONASS와 GPS(Global Positioning System)는 성능이 거의 동일하며 향후 GLONASS 시스템의 이용 확대가 기대된다.

IMO introduced e-Navigation concept to improve the efficiency of ship operation, port operation, and ship navigation technology. IMO proposed sixteen MSPs (Maritime Service Portfolio) applicable to the ships and onshore in case of e-Navigation implementation. In order to meet the demands of the international society, the system implementation work for the Korean e-Navigation has been specified. The Korean e-Navigation system has five service categories: the S2 service category, which is a ship anomaly monitoring service, is a service that classifies emergency levels according to the degree of abnormal condition when a ship has an abnormality in ship operation, and provides guidance for emergency situations. The navigation safety module is a sub-module of the S2 service that determines the emergency level in case of navigation equipment malfunctioning, engine or steering gear failure during navigation. It provides emergency response guidance based on emergency level to the abnormal ship. If an abnormal condition occurs during the ship operation, first, the ship shall determine the emergency level, according to the degree of abnormality of the ship. Second, an emergency response guidance is generated based on the determined emergency level, and the guidance is transmitted to the ship, which helps the navigators prevent accidents and not to spread. In this study, the operational concept for the implementation of the Korean e-Navigation system is designed and the concept is focused on the navigation safety module of S2 service.

In this study, a model-referenced underwater navigation algorithm is proposed for high-precise underwater navigation using monocular vision near underwater structures. The main idea of this navigation algorithm is that a 3D model-based pose estimation is combined with the inertial navigation using an extended Kalman filter (EKF). The spatial information obtained from the navigation algorithm is utilized for enabling the underwater robot to navigate near underwater structures whose geometric models are known a priori. For investigating the performance of the proposed approach the model-referenced navigation algorithm was applied to an underwater robot and a set of experiments was carried out in a water tank.

최근 해양 사고 및 그 피해가 증가함에 따라 선박의 안전 항해에 대한 관심이 높아지고 있다. 이에 해양 사고에 대한 규제를 강화 하고, 최신의 IT 기술들을 적용한 다양한 항해 장비들을 개발하여 항해사의 안전운항을 지원하고 있다. 그러나 너무 복잡하고 많은 정보를 무 분별하게 제공하는 경우가 많아 오히려 항해사의 의사결정에 방해가 되는 경우가 있어 정보를 표시하고 서비스하는 효율적인 방법에 대한 연 구가 필요한 실정이다. 이러한 배경으로 본 논문에서는 다양한 항해정보를 보다 직관적으로 제공하기 위한 방법으로 증강현실 기술을 적용하 였으며, 이를 통해 항해사가 신속하고 정확한 의사결정을 내릴 수 있도록 지원하는 증강현실 기반의 차세대 항해지원 시스템을 제안한다. 또 한, 구현된 요소 기능들은 선박운항 시뮬레이터 및 실선 시험을 통해 시스템의 적용 가능성과 효용성을 검증하였다.

This study presents a precise relative navigation algorithm using both laser and Global Positioning System (GPS) measurements in real time. The measurement model of the navigation algorithm between two spacecraft is comprised of relative distances measured by laser instruments and single differences of GPS pseudo-range measurements in spherical coordinates. Based on the measurement model, the Extended Kalman Filter (EKF) is applied to smooth the pseudo-range measurements and to obtain the relative navigation solution. While the navigation algorithm using only laser measurements might become inaccurate because of the limited accuracy of spacecraft attitude estimation when the distance between spacecraft is rather large, the proposed approach is able to provide an accurate solution even in such cases by employing the smoothed GPS pseudo-range measurements. Numerical simulations demonstrate that the errors of the proposed algorithm are reduced by more than about 12% compared to those of an algorithm using only laser measurements, as the accuracy of angular measurements is greater than 0.001° at relative distances greater than 30 km.

최근 해양안전에 대한 높은 관심과 ICT 기술의 비약적인 발전에 힘입어 선박에 다양한 디지털 장비들을 도입하는 전자항법체계인 e-Navigation이 크게 주목받고 있다. e-Navigation은 해양안전뿐만 아니라, 해양정보 서비스에서 새로운 ICT 패러다임을 제시하고 있다. 이 에 본 연구에서는 e-Navigation과 관련하여 IHO에서 제시하는 새로운 범용 수로데이터모델 S-100을 기반으로 표준화된 전자해도 및 해상정 보의 융합 서비스를 효율적으로 제공할 수 있는 Shore 기반의 해상정보 서비스 플랫폼을 제안하고자 한다. 제안된 Shore 기반 해상정보 서비 스 플랫폼은 기본적으로 전자해도와 날씨, 조류, AIS 정보 등의 센서정보, 그리고 육상지도 정보와의 융합 처리 및 웹 기반 서비스가 가능하 다. 또한, 이러한 플랫폼의 웹 서비스는 스마트 폰 또는 웹 패드의 모바일 단말기에서 간단한 WebApp 또는 App을 이용하여 전자해도 및 다 양한 해상정보 서비스의 활용을 가능하게 할 수 있다. 끝으로, 제안된 플랫폼은 기존의 S-57 전자해도와 더불어 S-101 표준을 지원할 수 있 으며, 웹 서비스 과정에서의 표준과 관련해서는 ISO 19100 시리즈 및 OGC의 공간정보 웹 서비스 표준을 지원한다.

This paper compares methods for attitude estimation of a UUV(Unmanned Underwater Vehicle). Attitude estimation plays a key role in underwater navigation using DVL(Doppler Velocity Log). The paper proposes attitude estimation methods using EKF(Extended Kalman Filter), UKF(Unscented Kalman Filter), and CF(Complementary Filter). It derives methods using the measurements from MEMS-AHRS(Microelectromechanical Systems-Attitude Heading Reference System) and DVL. The methods are used for navigation in a test pool and their navigation performance is compared. The results suggest that even if there is no measurement relative to some absolute landmarks, DVL-only navigation can be useful for navigation in a limited time and range.

대한민국 등대의 역사는 일제가 국외 침략을 목적으로 한반도에 설치한 것에서 시작되었다고 알려져 있다. 이러한 주장에 따르면 1903년 인천에 처음으로 등대가 설치된 이래 일제 강점기를 거치면서 근대적인 항로표지시스템이 구성되었다는 것이다. 그러나 이 점에 대해 서는 좀 더 신중하게 고려할 필요가 있다. 국제 항구의 도시로서 그리고 초량왜관의 도시로서 부산은 15세기 초 이래로 한일 외교관계의 중심 지였다. 그렇기 때문에 이미 오래전부터 부산에는 해상 국제교류를 위한 항만시설이 발달되었다. 그럼에도 불구하고 지금까지 해양에 관련된 역사자료가 부족하고 기초연구가 미비하여 올바른 역사를 정립하는 것이 어려운 실정이었다. 최근 들어서 부산해관 고문서의 번역이 마무리 되었고, 초량왜관 관련 고지도들을 집성한 자료가 편찬되면서 보다 객관적인 부산의 역사를 정립할 수 있게 되었다. 이러한 맥락에서 본 논문 은 고지도와 문서들을 통하여 오래된 국제 항구도시 부산의 초량항에 초점을 두고 부산 항로표지의 기원에 관하여 고찰하고자 한다.

The Global Positioning System (GPS) is widely used to aid the navigation of aerial vehicles. However, the GPS cannot be used indoors, so alternative navigation methods are needed to be developed for micro aerial vehicles (MAVs) flying in GPS-denied environments. In this paper, a real-time three-dimensional (3-D) indoor navigation system and closed-loop control of a quad-rotor aerial vehicle equipped with an inertial measurement unit (IMU) and a low-cost light detection and ranging (LIDAR) is presented. In order to estimate the pose of the vehicle equipped with the two-dimensional LIDAR, an octree-based grid map and Monte-Carlo Localization (MCL) are adopted. The navigation results using the MCL are then evaluated by making a comparison with a motion capture system. Finally, the results are used for closed-loop control in order to validate its positioning accuracy during procedures for stable hovering and waypoint-following.

As a sense of practical field, most researchers emphasize the importance of safety management to prevent marine accidents. The purpose of this paper is to develope a new safety evaluation method using Safety Index (SI) which is to measure the emotional feeling of navigation officer by traffic situations. In this study, the questionnaires with SI are used to investigate the degree of sensing levels of navigation officers according to the navigation situations. In addition, the traffic data obtained from AIS (Automatic Identification System) data are used to give actual situations in the questionnaire investigation. As results of questionaries investigations based upon the AIS data, it is shown that the Safety Index can be used as a criterion to determine the safety levels of ship navigating in a coastal areas.

This paper aims to identify what is needed to improve the English for Specific Purposes(ESP) curriculum for English as a Foreign Language(EFL) college learners at navigation school. Different needs from learners and experienced professionals are identified through diversified methods, and the findings from these are analysed and consolidated from a balanced point of view. For this purpose, putting learners at the centre of analysis, identifying their subjective and objective needs serves as a point of departure in formulating the curriculum. Then, the target situation is analysed according to the short-term aim of getting a job, followed by long-term needs for successfully fulfilling future duties as a pilot. Based on findings, it is suggested that ESP curriculum for learners in navigation studies should be focused on the successful language performance of their actual duties and tasks to be given in the future working situations, rather than on immediate needs for getting a job. In particular, special attention needs to be paid to enhancing learners’ productive language competences through a series of hands-on trainings and a wide range of extra-curricular activities, specifically for a higher command of oral communication. For this, not only ESP, curriculum for EGP(English for General Purposes) should be systematically structured as ESP-oriented EGP, and naturally move onto areas of ESP in a coherent manner.

2012년은 게라르드 메르카토르가 탄생한 지 500주년이 되는 해였다. 1512년에 태어난 메르카토르는 1569년 <항해자들이 활용 할 수 있도록 새롭게 증보된 지구전도>를 간행하였다. 총 18장으로 구성된 이 지도는 ‘항정선’을 직선으로 표시하여 항해용으로 활용할 목적으로 제작되었다. 이로 인해 고위도의 형상은 크게 확대되는 결과가 초래되었지만, 지도상의 두 지점을 연결하면 간단하게 선박의 침로를 직선으로 표시할 수 있다는 장점이 있었다. 메르카토르는 애초부터 1569년 세계 지도를 항해용으로 제작하였으나, 당시대에는 이 러한 장점이 널리 인식되지 못하였다. 그러나 1599년 에드워드 라이트와 1645년 헨리 본드 등의 수학자들이 그의 도법을 수학적으로 설명 하고 입증함으로써 메르카도르 도법은 항해용 해도의 표준이 되어 갔다. 그의 사후 450여년이 흐른 오늘날 전자해도도 메르카토르 해도 에 의거하여 제작된 것이라는 점에서 메르카토르는 항해사의 발전에 기여한 위대한 인물로 인식되어야 한다. 이 논설은 메르카토르 탄생 500주년을 기념하여 그의 삶과 메르카토르 해도, 그의 해도의 보급과 그로 인한 항해 안전에의 기여도 등을 정리한 것이다. 이를 통해 오 늘날 표준 항해용 해도로 널리 사용되고 있는 메르카토르 해도의 제작자로서 메르카토르가 항해사의 발전에 기여한 바를 재인식시키고 자 하였다.

In this paper, a robot vision technique is presented to detect obstacles, particularly approaching humans, in the images acquired by a mobile robot that autonomously navigates in a narrow building corridor. A single low-cost color camera is attached to the robot, and a trapezoidal area is set as a region of interest (ROI) in front of the robot in the camera image. The lower parts of a human such as feet and legs are first detected in the ROI from their appearances in real time as the distance between the robot and the human becomes smaller. Then, the human detection is confirmed by detecting his/her face within a small search region specified above the part detected in the trapezoidal ROI. To increase the credibility of detection, a final decision about human detection is made when a face is detected in two consecutive image frames. We tested the proposed method using images of various people in corridor scenes, and could get promising results. This method can be used for a vision-guided mobile robot to make a detour for avoiding collision with a human during its indoor navigation.