• Title, Summary, Keyword: RF localization

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Underwater Localization using RF Sensor and INS for Unmanned Underwater Vehicles (RF 센서와 INS을 이용한 UUV 위치 추정)

  • Park, Daegil;Kwak, Kyungmin;Jung, Jaehoon;Kim, Jinhyun;Chung, Wan Kyun
    • Journal of Ocean Engineering and Technology
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    • v.31 no.2
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    • pp.170-176
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    • 2017
  • In this paper, we propose an underwater localization scheme through the fusion of an inertial navigation system (INS) and the received signal strength (RSS) of electromagnetic (EM) wave sensors to guarantee precise localization performance with high sampling rates. In this localization scheme, the INS predicts the pose of the unmanned underwater vehicle (UUV) by dead reckoning at every step, and the RF sensors corrects the UUV position functions using the Earth-fixed reference when the UUV is located in underwater wireless sensor networks (UWSN). The localization scheme and state modeling were conducted in the extended Kalman filter framework, and UUV localization experiments were conducted in a basin environment. The scheme achieved reliable localization accuracy during long-term navigation, demonstrating the feasibility of exploiting EM wave attenuation as Earth-fixed reference sensors.

Indoor Positioning System Using Ultrasonic and RF (초음파와 RF를 이용한 실내 측위 시스템)

  • Zho, Back-doo;Kwon, Sung-oh;Cheon, Seong-eun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.42 no.2
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    • pp.413-423
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    • 2017
  • In this paper, we propose a ultrasonic and RF-based indoor localization system. In previous work, various systems were proposed for indoor localization, but they have limitation in applicability due to time-synchronization, complexity, or accuracy. To overcome such problems, an indoor localization system with ultrasonic and RF is proposed. A transmitting system is composed of a pair of ultrasonic and RF transmitters and the receiving system is composed of multiple ultrasonic receivers and one RF receiver. The theoretical performance limitation is also analyzed. To verify localization performance, we have implemented a receiving systems and a transmitting system using Arduino modules. Experiments were performed in $2m{\times}2m{\times}2m$ space and the localization errors had a mean of 6.1cm and a standard deviation of 1.6cm.

Analysis of Indoor Localization Technology for Exhibition Services and Application Method of VLC/RF Converged Localization (전시 서비스를 위한 실내 측위 기술 분석 및 VLC/RF 결합 측위 적용 방안)

  • Kim, Ki-Yun;Lee, Min-Woo;Cha, Jae-Sang
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.1
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    • pp.217-225
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    • 2015
  • Recently, as the supply of smart phone is spreading and the exhibition industries are rapidly growing, future exhibitions are evolving toward active, customized, interactive, tangible services, which can give more satisfaction to visitors. To realize this services, the indoor localization in the exhibition of visitors is very important and according to the accuracy of localization the quality of services for exhibition are also different. In this paper, state-of-the art indoor localization techniques are investigated and new localization method are proposed. To achieve this goal, future exhibition service types are proposed, which are connected with IT technology. And also, BLE(Bluetooth Low Energy) technology including comparison of specifications and representative localization technologies are analysed. Furthermore we performed comparison study and simulation between RF and VLC channels. Finally based on this, we proposed converged VLC and RF(Wi-Fi and BLE) localization technique for exhibition.

Spectral extrapolation for ultra-wide band radio frequency super-resolution tumor localization in the breast

  • Northardt, T.;Kasilingam, D.
    • Biomedical Engineering Letters
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    • v.7 no.1
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    • pp.25-30
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    • 2017
  • The use of ultra-wide band (UWB) radio frequency (RF) as an alternative to x-ray mammography for the detection and localization of breast tumors has been an area of focused research over the last decade. Unlike x-rays, UWB RF is non-ionizing and poses no risk of inducing cancer in examined patients. However, the reduction in operating frequency of UWB RF compared to x-rays results in much poorer localization when using classical space-time adaptive signal processing. This work investigates the synergistic use of a temporal signal spectrum extrapolation technique and contemporary basis pursuit de-noising (BPDN) beamforming to achieve medically relevant tumor localization accuracy within a heterogeneous simulated breast volume. If the beamforming process is viewed as a matched filtering operation, the spectrum extrapolation technique artificially increases the bandwidth of the received signal to afford much sharper correlations and hence contributing to increased localization accuracy. BPDN also contributes to increased localization accuracy by employing $L_1$-norm constraints which shows marked clutter suppression effects in this context.

Considerations for Design and Implementation of a RF Emitter Localization System with Array Antennas

  • Lim, Deok Won;Lim, Soon;Chun, Sebum;Heo, Moon Beom
    • Journal of Positioning, Navigation, and Timing
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    • v.5 no.1
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    • pp.37-45
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    • 2016
  • In this paper, design and implementation issues for a network-oriented RF emitter localization system with array antenna are discussed. For hardware, the problem of array mismatch and RF/IF channel mismatch are introduced and the calibration schemes for solving those problems are also provided. For software, it is explained how to overcome the drawback of conventional MUltiple Signal Identification and Classification (MUSIC) algorithm in a point of identifying the number of received signals and problems such as Data Association Problem and Ghost Node Problem in regard to multiple emitter localization are presented with some approaches for getting around those problems. Finally, for implementation, a criterion for arranging each of sensors and a requirement for alignment of array antenna' orientation are also given.

A Fine-grained Localization Scheme Using A Mobile Beacon Node for Wireless Sensor Networks

  • Liu, Kezhong;Xiong, Ji
    • Journal of Information Processing Systems
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    • v.6 no.2
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    • pp.147-162
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    • 2010
  • In this paper, we present a fine-grained localization algorithm for wireless sensor networks using a mobile beacon node. The algorithm is based on distance measurement using RSSI. The beacon node is equipped with a GPS sender and RF (radio frequency) transmitter. Each stationary sensor node is equipped with a RF. The beacon node periodically broadcasts its location information, and stationary sensor nodes perceive their positions as beacon points. A sensor node's location is computed by measuring the distance to the beacon point using RSSI. Our proposed localization scheme is evaluated using OPNET 8.1 and compared with Ssu's and Yu's localization schemes. The results show that our localization scheme outperforms the other two schemes in terms of energy efficiency (overhead) and accuracy.

Improved Ultrasonic Satellite System for the Localization of Mobile Robots (이동로봇의 위치측정을 위한 개선된 초음파 위성 시스템)

  • Kim, Su-Yong;Yoon, Kang-Sup
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.12
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    • pp.1240-1247
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    • 2011
  • The localization of mobile robot in environment is a major concern in mobile robot navigation. So, many kinds of localization techniques have been researched for several years. Among them, the positioning system using ultrasound has received attention. Most of these ultrasonic positioning systems to synchronize the transmitters and receivers are used for RF (Radio Frequencies). However, due to the use of RF, the interference problems can not be avoided and the performance of radio frequencies directly affects the positioning performance. So we proposed the ultrasonic positioning system without synchronizing RF. The proposed system is based on existing USAT (Ultrasonic Satellite System) adopted infrastructure transmitting type, and consists of transmitter and receiver synchronizing modules instead of the radio frequency transmitters and receiver. The ultrasonic transmitters and receivers are synchronized individually by the transmitter and receiver synchronizing modules. In order to calculate the bias between the transmitter and receiver synchronizing modules, new positioning algorithm similar to GPS was proposed. The positioning performance of the improved USAT without synchronizing RF and the validity of the proposed positioning algorithm are verified and evaluated by experiments.

MR spectroscopy using single-shot RF localization technique (단일 RF 펄스를 사용한 3차원 체적 선택 방법을 이용한 MR 스펙트로 스코피)

  • Rim, C.Y.;Chun, K.W.;Ra, J.B.;Cho, Z.H.
    • Proceedings of the KOSOMBE Conference
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    • v.1989 no.05
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    • pp.51-54
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    • 1989
  • In last several years, a number of volume localization techniques, such as ISIS, VSE, SPARS and STEAM etc., have been developed for the MR spectroscopy. These localizing techniques, however, require application of several RF pulses for the 3-D volume selection and suffer from T1 and T2 decays due to relatively long RF excitation time. In this paper, we propose a single-shot RF pulse localization technique to achieve the localized 3-D volume selection. This technique combines the cylindrical volume selection technique with a radial gradient coil with single-shot RF pulse and the oscillating selection gradient technique, so thai it minimizes the volume selection time. We report some experimental results obtained with the proposed method which appears promising for 3-D volume imaging and localized spectroscopy.

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A Distance Estimation Scheme Based on WLAN RF Properties for Localization of Mobile Terminals (WLAN 전파특성 기반 실내 위치설정을 위한 이동단말의 거리추정 기법)

  • Yang, Jeong-Woo;An, Gae-Il;Kim, Shin-Hyo;Chung, Byung-Ho;Kim, Tae-Yeon;Pyun, Ki-Hyun;Cho, Gi-Hwan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39B no.7
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    • pp.449-458
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    • 2014
  • In the context-aware services, localization is an important technical element. Due to the easy to use and low cost, it was widely enabled with RF properties such as RSSI. However, RSSI is known to be not appropriated for indoor localization, because it tends to show big variance in time and is greatly effected with the multipath. This paper proposes a distance estimation process and its constituted methods for indoor localization, by making use of the other WLAN's RF property, CSI(Channel State Information). Firstly we define a comprehensive localization process, and suggest a calibration algorithm of environment factors in the path loss propagation model. Then, by implementing them with a commercial WLAN module, an the proposed process and methods are evaluated in terms of usefulness.

Indoor Positioning System using Geomagnetic Field with Recurrent Neural Network Model (순환신경망을 이용한 자기장 기반 실내측위시스템)

  • Bae, Han Jun;Choi, Lynn;Park, Byung Joon
    • The Journal of Korean Institute of Next Generation Computing
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    • v.14 no.6
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    • pp.57-65
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    • 2018
  • Conventional RF signal-based indoor localization techniques such as BLE or Wi-Fi based fingerprinting method show considerable localization errors even in small-scale indoor environments due to unstable received signal strength(RSS) of RF signals. Therefore, it is difficult to apply the existing RF-based fingerprinting techniques to large-scale indoor environments such as airports and department stores. In this paper, instead of RF signal we use the geomagnetic sensor signal for indoor localization, whose signal strength is more stable than RF RSS. Although similar geomagnetic field values exist in indoor space, an object movement would experience a unique sequence of the geomagnetic field signals as the movement continues. We use a deep neural network model called the recurrent neural network (RNN), which is effective in recognizing time-varying sequences of sensor data, to track the user's location and movement path. To evaluate the performance of the proposed geomagnetic field based indoor positioning system (IPS), we constructed a magnetic field map for a campus testbed of about $94m{\times}26$ dimension and trained RNN using various potential movement paths and their location data extracted from the magnetic field map. By adjusting various hyperparameters, we could achieve an average localization error of 1.20 meters in the testbed.