• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2012년도 춘계학술발표대회
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• pp.961-963
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• 2012

The sound source localization system is used to some area such as robotic system, object localization system, guarding system and medicine. So time delay estimation and angle estimation of sound direction are studied until now. These days time delay estimation is described in LabVIEW which is used to create innovative computer-based product and deploy measurement and control systems. In this paper, the development of signal monitoring platform is presented for sound source localization. This platform is designed in virtual instrument program and implemented in two stages. In first stage, data acquisition system is proposed and designed to analyze time delay estimation using cross correlation. In second stage, data obtaining system which is applied and designed to monitor analog signal processing is proposed.

• 전기학회논문지
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• 제58권10호
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• pp.2047-2051
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• 2009

In this paper, we propose the localization method on WSN(Wireless Sensor Network) using fuzzy model and Kalman filter. The proposed method is as follows: First, we estimate the distance of RSSI(Receive Signal Strength Index) by using fuzzy model in order to minimize the distance error. Second, we use a triangulation measurement for estimating the localization. And then, we minimize the localization error using a Kalman filter. Finally, we show the effectiveness and feasibility of the proposed method through some experiments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권1호
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• pp.87-107
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• 2015

Considering the localization estimation issue in mixed line-of-sight (LOS)/non-LOS(NLOS) environments based on received signal strength (RSS) measurements in wireless sensor networks, a grid-based correlation method based on the relationship between distance and RSS is proposed in this paper. The Maximum-Likelihood (ML) estimator is appended to further improve the localization accuracy. Furthermore, in order to reduce computation load and enhance performance, an improved recursively version with NLOS mitigation is also proposed. The most advantages of the proposed localization algorithm is that, it does not need any prior knowledge of the propagation model parameters and therefore does not need any offline calibration effort to calibrate the model parameters in harsh environments, which makes it more convenient for rapid implementation in practical applications. The simulation and experimental results evidence that the proposed localization algorithm exhibits good localization performance and flexibilities for different devices.

• Journal of Positioning, Navigation, and Timing
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• 제10권1호
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• pp.49-54
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• 2021

Indoor positioning system becomes of increasing interests due to the demands for accurate indoor location information where Global Navigation Satellite System signal does not approach. Wi-Fi access points (APs) built in many construction in advance helps developing a Wi-Fi Received Signal Strength Indicator (RSSI) based indoor localization. This localization method first collects pairs of position and RSSI measurement set, which is called fingerprint database, and then estimates a user's position when given a query measurement set by comparing the fingerprint database. The challenge arises from nonlinearity and noise on Wi-Fi RSSI measurements and complexity of handling a large amount of the fingerprint data. In this paper, machine learning techniques have been applied to implement Wi-Fi based localization. However, most of existing indoor localizations focus on single position estimation. The main contribution of this paper is to develop multi-target localization by using deep neural, which is beneficial when a massive crowd requests positioning service. This paper evaluates the proposed multilocalization based on deep learning from a multi-story building, and analyses its learning effect as increasing number of target positions.

• 대한전자공학회논문지TC
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• 제48권6호
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• pp.51-60
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• 2011

GPS 신호를 수신할 수 없는 실내 지역에 적용하기 위하여 무선 센서 네트워크를 이용한 측위 연구가 진행 중이며 많은 알고리즘들이 제안되고 있다. 기존 알고리즘들 중 WCL(Weighted Centroid Localization)은 하드웨어적으로 제한된 무선 센서 네트워크의 특성을 고려하여 간단한 연산으로 사용자 노드의 좌표를 계산하면서 성능 면에서도 우수함이 입증되어 있다. 그러나 최적의 성능을 얻기 위하여 항상 고정 노드들이 전체 네트워크 범위의 96%로 신호를 전송해야 하는 점과 각 고정 노드의 전송 범위 외곽지역에서 급격한 측위 오차가 발생하여 평균 오차와 편차가 크다는 단점이 있어 실제 실내 환경에 적용시키기 어려운 측면이 있다. 본 논문에서는 각 고정 노드의 신호 세기를 비교하여 사용자 노드가 존재할 가능성이 있는 추정 구역을 순차적으로 좁혀 나가는 측위 알고리즘을 제안하였다. 추정 구역을 최소화 하여 사용자 노드의 위치를 계산함으로써 고정 노드의 전송 범위에 따른 성능 저하와 외곽지역에서 발생하는 최대 오차 문제를 해결하였으며, 평균 오차도 자유공간 전파 환경에서 WCL 알고리즘 보다 5배 정도 감소하는 것을 시뮬레이션을 통해 검증하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권4호
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• pp.670-691
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• 2013

In RSSI-based RFID(Radio Frequency IDentification) indoor localization system, the signal path loss model of each sub-region is different from others in the whole localization area due to the influence of the multi-path phenomenon and other environmental factors. Therefore, this paper divides the localization area into many sub-regions and constructs separately the signal path loss model of each sub-region. Then an improved LANDMARC method is proposed. Firstly, the deployment principle of RFID readers and tags is presented for constructing localization sub-region. Secondly, the virtual reference tags are introduced to create a virtual signal strength space with RFID readers and real reference tags in every sub-region. Lastly, k nearest neighbor (KNN) algorithm is used to locate the target object and an error compensating algorithm is proposed for correcting localization result. The results in real application show that the new method enhances the positioning accuracy to 18.2% and reduces the time cost to 30% of the original LANDMARC method without additional tags and readers.

• 센서학회지
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• 제26권3호
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• pp.199-203
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• 2017

In this paper, we developed an underwater localization system for underwater robot docking using the electromagnetic wave attenuation model. Electromagnetic waves are generally known to be impossible to use in water environment. However, according to the conclusions of the previous studies on the attenuation characteristics in underwater, the attenuation pattern is uniform and its model was accurately proposed and verified in 3-dimensional space via the omnidirectional antenna. In this paper, a docking structure and localization sensor system are developed for a widely used cone type docking mechanism. First, we fabricated electromagnetic wave range sensor transmit modules. And a mobile sensor node is equipped with unmanned underwater vehicle(UUV)s. The mobile node senses the four different signal strength (RSS: Received Signal Strength) from fixed nodes, and the obtained RSS data are transformed to each distance information using the 3-Dimensional EM wave attenuation model. Then, the relative localization between the docking area and underwater robot can be achieved according to optimization algorithm. Finally, experimental results show the feasibility of the proposed localization system for the docking induction by comparing the errors in the actual position of the mobile node and the theoretical position through the model.

• Journal of information and communication convergence engineering
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• 제10권4호
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• pp.349-358
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• 2012

Over a wireless sensor network (WSN), accurate localization of sensor nodes is an important factor in enhancing the association between location information and sensory data. There are many research works on the development of a localization algorithm over three-dimensional (3D) space. Recently, the complexity-reduced 3D trilateration localization approach (COLA), simplifying the 3D computational overhead to 2D trilateration, was proposed. The method provides proper accuracy of location, but it has a high computational cost. Considering practical applications over resource constrained devices, it is necessary to strike a balance between accuracy and computational cost. In this paper, we present a novel 3D localization method based on the received signal strength indicator (RSSI) values of four anchor nodes, which are deployed in the initial setup process. This method provides accurate location estimation results with a reduced computational cost and a smaller number of anchor nodes.

• 제어로봇시스템학회논문지
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• 제19권2호
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• pp.107-112
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• 2013

In this paper, we discuss a 3-dimensional localization sensor node using EM waves (Electromagnetic waves) with RSSI (Received Signal Strength Indicator). Generally EM waves cannot be used in underwater environment, because the signal is highly attenuated by the water medium according to the distance. Although the signal quickly reduces in underwater, the reducing tendency is very clear and uniform. Hence EM waves have possibility as underwater distance sensors. The authors have verified the possibility by theory and several experiments, and developed calibration methods in case of linear and planer environment. For 3-dimensional localization in underwater, it must be known antenna's radiation pattern property in electric plane(called E-plane). In this paper, we proceed experiments to verify attenuation tendency with z axis movement, PLF (Polarization Loss Factor) and ILF (Inclination Loss Factor) with its theoretical approach.

• 한국소음진동공학회논문집
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• 제21권3호
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• pp.220-226
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• 2011

This paper presents the novel work for source localization of serial multiple impacts in a plate sructure. It is difficult to identify the source of serial multiple impacts with the current source localization techenology(SLT) because of the overlapping of dispersive wave induced by multiple impacts and the reflaction from the edge of the plate. In this paper, the new method is suggested for source localization. The method is developed based on the SLT with pre-signal processing such as some limitation for the selection of three sensors, the frequency range for TFA and impact time interval. Results from numerical simulation and experiment in isotropic plate structure are presented, which show the capability of the proposed method.