• Journal of Positioning, Navigation, and Timing
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• 제12권4호
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• pp.399-408
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• 2023

In this paper, we propose a solution that enables continuous indoor/outdoor positioning of smartphone users through the integration of Pedestrian Dead Reckoning (PDR) and GPS/WiFi signals. Considering that accurate step detection affects the accuracy of PDR, we propose a Deep Neural Network (DNN)-based technology to distinguish between walking and non-walking signals such as walking in place. Furthermore, in order to integrate PDR with GPS and WiFi signals, a technique is used to select a proper measurement by distinguishing between indoor/outdoor environments based on GPS Dilution of Precision (DOP) information. In addition, we propose a technology to adaptively change the measurement error covariance matrix by detecting measurement outliers that mainly occur in the indoor/outdoor transition section through a residual-based χ² test. It is verified through experiments on a testbed that these technologies significantly improve the performance of PDR and PDR/GPS/WiFi fingerprinting-based integrated pedestrian navigation.

• IEIE Transactions on Smart Processing and Computing
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• 제4권3호
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• pp.173-182
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• 2015

A real-time, Indoor navigation systems utilize ultra-wide band (UWB), radio-frequency identification (RFID) and received signal strength (RSS) techniques that encompass WiFi, FM, mobile communications, and other similar technologies. These systems typically require surplus infrastructure for their implementation, which results in significantly increased costs and complexity. Therefore, as a solution to reduce the level of cost and complexity, an inertial measurement unit (IMU) and quick response (QR) codes are utilized in this paper to facilitate navigation with the assistance of a smartphone. The QR code helps to compensate for errors caused by the pedestrian dead reckoning (PDR) algorithm, thereby providing more accurate localization. The proposed algorithm having IMU in conjunction with QR code shows an accuracy of 0.64 m which is higher than existing indoor navigation techniques.

• Journal of Positioning, Navigation, and Timing
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• 제13권3호
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• pp.289-299
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• 2024

In the Pedestrian Dead Reckoning (PDR)/Global Positioning System (GPS)/Wi-Fi-integrated navigation system for indoor/outdoor continuous positioning of pedestrians, the process of detecting outliers in measurements is very important. When accurate location information from measurements is used, reliable correction data can be generated during the fusion filtering process. However, abnormal measurements may occur in certain situations, such as indoor/outdoor transitions, which can degrade filter performance and lead to significant errors in the estimated position. To address this issue, this paper proposes a method for detecting outliers in measurements based on Rényi Divergence (RD). When the deviation of the RD value is large, the measurements are considered outliers, and positioning is performed using only pure PDR. Based on experiments conducted with real data, it was confirmed that outliers were effectively detected for abnormal measurements, leading to an improvement in the performance of pedestrian navigation.

• 한국인터넷방송통신학회논문지
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• 제19권1호
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• pp.133-138
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• 2019

스마트폰을 이용한 실내 항법 시스템은 대형 실내 시설에서 사용자의 위치 기반 서비스를 위해 매우 중요한 기반 기술이다. 이를 위해서 스마트폰에 내장된 가속도 센서와 자이로 센서를 이용하여 사용자의 이동 거리와 방향을 추정할 수 있다면 추가적인 외부 환경이 필요 없으므로 매우 유용한 기술이 된다. 본 논문은 일반적인 스마트폰에 Pedestrian Dead Reckoning(PDR) 기술과 칼만 필터를 적용하여, 사용자가 스마트폰을 가슴 앞에 잡고서 이동하면서 위치를 추적하는 실내에서의 항법 시스템 기술에 관한 것이다. 특히 회전 방향각을 추정하기 위하여 확장 칼만 필터가 설계되었고 실험적으로 일정속도로 보행하는 경우에 그 성능이 검증되었다.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1491-1496
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• 2009

Because of the development of advanced construction technology, the inner environments of building become more and more complicated, which may result in many problems. The administer may forget where they put up the certain picture, and search for it all over the building, or they underestimate the number of the visitors, and find the situation is out of control, while the pedestrian may get lost, and after making their efforts, they found they turned back to the origin point again. So it is very necessary to establish an indoor spatial database. On one hand, it is able to assist administrator to manage the property and human flow inside the building, on the other hand it could help the pedestrian find the way easily especially when they are not familiar with the building or there is an emergency. This paper focused on how to create the indoor spatial database including both static database and moving objects database. The static database is built on the basis of 3D building models, and the moving objects database gets information from many kinds of cameras and sensors installed in the building. And at the same time the paper discussed the practical use of indoor spatial database mainly in three aspects including consistency management, building restructure, and pedestrian navigation.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.251-256
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• 2006

In the work package 'Integrated Positioning' of the research project NAVIO (Pedestrian Navigation Systems in Combined Indoor/Outdoor Environements) we are dealing with the navigation and guidance of visitors of our University. Thereby start points are public transport stops in the surroundings of the Vienna University of Technology and the user of the system should be guided to certain office rooms or persons. For the position determination of the user different location sensors are employed, i.e., for outdoor positioning GPS and dead reckoning sensors such as a digital compass and gyro for heading determination and accelerometers for the determination of the travelled distance as well as a barometric pressure sensor for altitude determination and for indoor areas location determination using WiFi fingerprinting. All sensors and positioning methods are combined and integrated using a Kalman filter approach. Then an optimal estimate of the current location of the user is obtained using the filter. To perform an adequate weighting of the sensors in the stochastic filter model, the sensor characteristics and their performance was investigated in several tests. The tests were performed in different environments either with free satellite visibility or in urban canyons as well as inside of buildings. The tests have shown that it is possible to determine the user's location continuously with the required precision and that the selected sensors provide a good performance and high reliability. Selected tests results and our approach will be presented in the paper.

• Journal of Positioning, Navigation, and Timing
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• 제11권1호
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• pp.35-44
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• 2022

In this paper, a dual foot (DF)-PDR system is proposed for the fusion of integration (IA)-based PDR systems independently applied on both shoes. The horizontal positions of the two shoes estimated from each PDR system are fused based on a particle filter. The proposed method bounds the position error even if the walking time increases without an additional sensor. The distribution of particles is a non-Gaussian distribution to express the lateral error due to systematic drift. Assuming that the shoe position is the pedestrian position, the multi-modal position distribution can be fused into one using the Gaussian sum. The fused pedestrian position is used as a measurement of each particle filter so that the position error is corrected. As a result, experimental results show that position of pedestrians can be effectively estimated by using only the inertial sensors attached to both shoes.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제23권4호
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• pp.210-216
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• 2017

본 논문은 지구 자기장 기반의 지문인식과 추측 항법을 사용하여 실시간으로 실내 위치정보 서비스를 사용자에 제공할 수 있는 알고리즘 및 솔루션을 제안한다. 지자기장 값의 변화 추이와 사전에 입력된 지자기장 값의 유사도를 판별하여 초기 위치를 추정하였으며 초기 위치에서 지자기장 지문인식과 추측 항법 상호 보정을 통해 보다 연속적인 이동 위치 추정을 함으로서 일부 5m가 넘어가는 지구 자기장의 최대 오차와 추측 항법의 누적 오차를 개선하였다. 그 뿐만 아니라 본 기법은 기존 지문인식 방법과는 달리 무선랜 AP등 인프라 구축을 제거하여 보다 경제적인 서비스 제공을 가능하게 한다.

• 한국항행학회논문지
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• 제17권6호
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• pp.810-815
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• 2013

구조 요원 위치 추적을 위해 Wi-Fi 기반 위치 추적 기술을 이용하는 경우, 거리 측정 정보를 제공하지 않는 Wi-Fi의 특성상 RSSI 핑거프린트 데이터베이스나 신호 감쇄 모델을 이용하여 거리측정치를 생성해 내어야 한다. 그러나 구조 현장에서 임시로 구축되는 데이터 통신 네트워크에서는 사전에 데이터베이스 구축이 어려워 적용이 곤란하다. 본 논문에서는 이러한 한계를 극복하기 위해 통신 네트워크 구축을 위해 사용된 전개식 AP의 근접 정보와 보행 항법 정보를 이용하여 복수 구조 요원의 위치 추적 방법을 연구하였다.

• 한국지리정보학회지
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• 제10권1호
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• pp.1-9
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• 2007

최근 들어 보행자 내비게이션을 위한 3차원 공간데이터의 요구가 급증하고 있다. 보행자 내비게이션에 있어서, 3차원 모델은 일반인의 시각에서 구체적으로 표현되어야 할 필요가 있다. 보행자 내비게이션을 위한 공간을 상세하게 구현하기 위해서는 실외 환경뿐만 아니라 지하쇼핑센터와 같은 실내 환경에서도 적용될 수 있는 3차원 모델을 개발하는 것이 필수적이다. 그러나 GPS 없이 모바일 맵핑만으로 3차원 데이터를 효율적으로 취득하기란 대단히 어렵다. 본 연구에서는 3차원 형상을 레이저 스캐너로 측정하고, 표면 텍스쳐는 CCD 센서로 취득하였으며, 계속적으로 변화하는 센서의 위치와 높이는 IMU를 통해 측정하였다. 또한 IMU의 위치데이터는 GPS의 위치보정 없이 CCD 이미지의 상대 표정을 통해 수정하였다. 연구결과로써, 디지털 카메라 및 레이저 스캐너와 IMU와의 통합을 통해 실내 환경에서 신뢰성 높고, 빠르며, 간편하게 3차원 공간 데이터를 취득할 수 있는 방법을 제안하였다.