• Journal of Positioning, Navigation, and Timing
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• v.1 no.1
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• pp.51-57
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• 2012

In this paper, design of an error model is presented in which the bias characteristic of the MEMS IMU is taken into consideration for performance enhancement of the MEMS IMU-based GPS/INS integrated navigation system. The drift bias of the MEMS IMU is modeled as a 1st-order Gauss-Markov (GM) process, and the autocorrelation function is obtained from the collected IMU data, and the correlation time is estimated from this. Prior to obtaining the autocorrelation function, the noise of IMU data is eliminated based on wavelet. As a result of simulation, it is represented that the parameters of error model can be estimated correctly only when a proper denoising is performed according to dynamic behavior of drift bias, and that the integrated navigation system based on error model, in which the drift bias is considered, provides more correct navigation performance compared to the integrated navigation system based on error model in which the drift bias is not considered.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.145-150
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• 2006

The paper deals with integrated navigation and sense & avoid systems for small unmanned aerial vehicles (UAV). First an introduction to the current UAV activities of the institute is given. It is followed by an overview about the integrated navigation system developed for small UAVs. The system is based on a tightly-coupled GPS/INS architecture. But instead of using delta-ranges, time-differenced carrier phases are used to aid the INS. Finally, results from navigation filter validation in flight tests are presented. After that an overview about sense and avoid strategies for application in small unmanned aircraft is given. From this a guideline for developing such a system for the institute's UAVs is presented.

• Spatial Information Research
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• v.11 no.1
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• pp.33-40
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• 2003

For effective management of information about establishment and repair of road and road facilities, we built GPS-Van mapping system that CCD Cameras, GPS receivers and INS are integrated and using it surveyed test area. Suggested a scheme that possible put acquired data into photo database systematically. Prototype of road facilities management system using the database shows us that extraction of qualitative information and management are possible through relation attribute information. And it raise cognitive faculty of user about objects using field photographs.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.677-685
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• 2011

In order to enhance public transportation and to maintain information credibility, improvement of accuracy regarding route and positional information of public transport is very significant. There have been a variety of methods using GPS to measure accuracy of location-based services. However, the researches of evaluation regarding kinematic position of linear objects measured by vehicle/kinematic GPS are still insufficient. That's why our paper aims to suggest method of evaluation accuracy on a real-time bus route surveyed by GPS by SBM(Single Buffering Method). To make it come true, we compared the findings on the static and dynamic positioning by using PP(Point Positioning), DGPS and GPS/INS integrated systems and analyzed the accuracy and error effects among them, focusing on Anyang city. Consequently, we can find out that in case of P.P. comparing positioning accuracy between RTK DGPS and GPS/INS, both of them have survey result within a margin of error of 5m. More importantly, we can evaluate positional accuracy of each GPS system based on the work provision of a public survey such as error for P.P.(14.5m, 18.1m), DGPS(16.9m, 18.5m), and GPS/INS(18.4m, 18.5m). We are expecting that proposed method in our paper can be utilized in a wide range of categories such as feasibility testing of GPS field survey and high accuracy of positioning for Bus Information System.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1152-1154
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• 2003

The needs of 3-D data have been increasing for various applications like visualization, 3-D modeling, planning and management as well as entertainment. Mobile mapping has become a quick and practical means for acquiring necessary 3-D data for above-mentioned applications. A mobile mapping system mainly consists of two main components, viz. data acquisition devices and positioning devices. The data acquisition devices consist of CCD cameras or/and laser scanners. The positioning devices consist of GPS, INS, Odometer (shaft encoder) and some other referencing devices. The overall accuracy of mobile mapping system depends on the accuracy of positioning devices and their integrated output. Though, GPS is the main input device for the position information, the signal is not available for the computation of position all the times in urban area. The GPS satellites are normally obstructed by high-rise buildings. Thus it is very important to understand the accuracy of such a system in different environments and means to solve such problems. We have developed a mobile mapping system called VLMS (Vehicle-borne Laser Mapping System), which consists of CCD Cameras, Laser scanners, GPS, INS and Odometer. In this paper, we will present and discuss the accuracy of this system with data acquired in different environments (open area, urban area, tunnel, express way etc) by analyzing the data with respect to other existing digital data.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.3
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• pp.68-79
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• 2008

Ground vehicle borne system which is named RoSSAV(Road Safety Survey and Analysis Vehicle) developed in KICT(Korea Institute of Construction Technology) can collect road geometric data. This system therefore is able to evaluate the road safety and analyze road deficient sections using data collected along the roads. The purpose of this study is to extract road geometric data for 3D road modeling in dangerous road section and The system should be able to quickly provide more accurate data. Various sensors(circular laser scanner, GPS, INS, CCD camera and DMI) are installed in moving object and collect road environment data. Finally, We extract 3d road geometry(center, boundary), road facility and slope using integrated multi-sensor data.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.114.3-114
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• 2001

The pure navigation system using Inertial Navigation Unit(INU) which has very accurate short term stabilities but not long term gives rise to position errors propotional to time. On the contrary, Global Positioning System(GPS) which is bounded its errors to some fixed ranges shows higher accuracy in the long term, and lower accuracy in the short term than that of INS. Recently the integration of these two systems is one of the main topic in the field of navigation system. In this thesis, the implementation of kalman filter on the real time navigation computer and step jump error compensation method is suggested.

• Journal of Ocean Engineering and Technology
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• v.33 no.5
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• pp.470-478
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• 2019

Because the global positioning system (GPS) is not available in underwater environments, an inertial navigation system (INS)/doppler velocity log (DVL) integrated navigation system is generally implemented. In general, an INS/DVL integrated system adopts a loosely coupled method. However, in this loosely coupled method, although the measurement equation for the filter design is simple, the velocity of the body frame cannot be accurately measured if even one of the DVL transducer signals is not received. In contrast, even if only one or two velocities are measured by the DVL transducers, the tightly coupled method can utilize them as measurements and suppress the error increase of the INS. In this paper, a filter was designed to regenerate the measurements of failed transducers by taking advantage of the tightly coupled method. The regenerated measurements were the normal DVL transducer measurements and the estimated velocity in RPM. In order to effectively estimate the velocity in RPM, a filter was designed considering the effects of the tide. The proposed filter does not switch all of the measurements to RPM if the DVL transducer fails, but only switches information from the failed transducer. In this case, the filter has the advantage of being able to be used as a measurement while continuously estimating the RPM error state. A Monte Carlo simulation was used to determine the performance of the proposed filters, and the scope of the analysis was shown by the standard deviation ($1{\sigma}$, 68%). Finally, the performance of the proposed filter was verified by comparison with the conventional tightly coupled method.

• 한국공간정보시스템학회:학술대회논문집
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• 1999.06a
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• pp.217-228
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• 1999

최근 범국가적인 GIS구축사업을 위한 효율적인 지형공간정보취득기법에 대한 요구가 날로 증가하고 있다. 이는 HW, SW 및 데이터로 구성되는 GIS구축에서 지형자료가 차지하는 비중과 이의 취득에 필요한 노력이 매우 중요함을 반증하고 있다. 이에 부응하여 국내에서도 재래식측량기법의 자동화/현대화에서부터 GPS측량기술의 도입, Airborne-항공사진측량기법의 개발 및 고해상도위성영상의 활용방안에 이르기까지 새로운 측량기술에 대한 다양한 연구와 기술축적을 서두르고 있는 실정이다. 그러나 위의 어떠한 측량기법도 단독으로는 정확도, 신속성, 경제성, 현재성 등 GIS 자료취득의 모든 요구조건을 만족하는 Total Solution이 되지 못하고 있다. 따라서 본 연구에서는 매핑과 GIS-자료취득에 활용되고 있는 여러 가지 항공측량기술의 현황과 장단점을 살펴보았다. 또한 위성에 의한 위치결정시스템인 GPS와 관성항행장치인 INS를 결합하여 항공측량 분야에 필요한 센서의 위치와 회전각을 결정하므로서 시너지(Synergy)효과를 높이는 기법을 소개한다.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.47.2-47
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• 2002

$\textbullet$ Introduction of aviation navigation $\textbullet$ Integrated navigation algorithm $\textbullet$ Description of hardware system $\textbullet$ Ground test $\textbullet$ Flight test $\textbullet$ Conclusion