• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2857-2863
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• 2014

IR-UWB has been developed as a standard of indoor ranging technology, because it has robust and good transmission characteristics in indoor environments and it can be operated with low power. In this paper, a IR-UWB packet analyzer is designed and implemented based on IEEE 802.15.4a, which is useful in developing IR-UWB real time location system with resolution of a few ten centimeters. A sniffer device of the packet analyzer monitors IR-UWB wireless networks, captures MAC packet frames, and transmits packet frames to the packet analyzing computer. The packet analyzing program in a computer analyzes received MAC packet frames and displays parsed packet information for developing engineers. Developed packet analyzer is used to analyze IEEE 802.15.4a MAC protocol, and also it can be used in other IEEE 802 series MAC protocol by modifying some functions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.11
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• pp.2252-2260
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• 2015

In this paper, we propose a vehicular cooperative navigation system using GNSS, vision sensor and radar sensor that are frequently used in mass-produced cars. The proposed cooperative vehicular navigation system is a variant of the Hybrid-Sum Product Algorithm over Wireless Network (H-SPAWN), where we use vision and radar sensors instead of radio ranging(i.e.,UWB). The performance is compared and analyzed with respect to the sensors, especially the position estimation error decreased about fifty percent when using radar compared to vision and radio ranging. In conclusion, the proposed system with these popular sensors can improve position accuracy compared to conventional cooperative navigation system(i.e.,H-SPAWN) and decrease implementation costs.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.2
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• pp.213-219
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• 2013

Recently, with the rapid advancement in information and communication technology, indoor location-based services(LBSs) that require precise position tracking have been actively studied with outdoor-LBS using GPS. However, in case of a ship which consists of steel structure, it is difficult to measure a precise localization due to significant ranging error by the diffraction and refraction of radio waves. In order to reduce location measurement errors that occur in these indoor environments, this paper presents distance compensation algorithms that are suitable for a narrow passage such as ship corridors without any additional sensors by using UWB(Ultra-wide-band), which is robust to multi-path and has an error in the range of a few centimeters in free space. These improvement methods are that Pythagorean theory and adjacent node technique are used to solve the distance error due to the node deployment and distance variation analysis technique is applied to reduce the ranging errors which are significantly fluctuated in the corner section. The experimental results show that the number of nodes and the distance error are reduced to 66% and 57.41%, respectively, compared with conventional CSS(Chirp spread spectrum) method.

• Journal of Positioning, Navigation, and Timing
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• v.6 no.3
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• pp.105-116
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• 2017

Several wireless localization algorithms are evaluated for the IR-UWB-based indoor location with the assumption that the ranging measurements contain the channelwise Non-Calibration Error (NCE). The localization algorithms can be divided into the Model-free Localization (MfL) methods and Model-based Kalman Filtering (MbKF). The algorithms covered in this paper include Iterative Least Squares (ILS), Direct Solution (DS), Difference of Squared Ranging Measurements (DSRM), and ILS-Common (ILS-C) methods for the MfL methods, and Extended Kalman Filter (EKF), EKF-Each Channel (EKF-EC), EKF-C, Cubature Kalman Filter (CKF), and CKF-C for the MbKF. Experimental results show that the DSRM method has better accuracy than the other MfL methods. Also, it demands smallest computation time. On the other hand, the EKF-C and CKF-C require some more computation time than the DSRM method. The accuracy of the EKF-C and CKF-C is, however, best among the 9 methods. When comparing the EKF-C and CKF-C, the CKF-C can be easily used. Finally, it is concluded that the CKF-C can be widely used because of its ease of use as well as it accuracy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.327-332
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• 2017

As Internet of Things (IoT) technology advances, there is a growing demand for location-based services (LBSs) to identify users' mobility and identity. The initial LBS system was mainly used to measure position information by measuring the phase of a signal transmitted from a global positioning system (GPS) satellite or by measuring distance to a satellite by tracking the code of a carrier signal. However, the use of GPS satellites is ineffective, because it is difficult to receive satellite signals indoors. Therefore, research on wireless communications systems like ultra-wide band (UWB), radio frequency identification (RFID), and ZigBee are being actively pursued for location recognition technology that can be utilized in an indoor environment. In this paper, we propose an LBS system that includes the 2.45GHz band for chirp spread spectrum (CSS), and the 3.1-10.6GHz band and the 250-750MHz bands for UWB using the IEEE 802.15.4a standard for low power-based location recognition. As a result, we confirmed that the 2.45GHz Industrial, Scientific and Medical (ISM) band RF transceiver and the ranging function can be realized in the hardware and has 0dBm output power.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11A
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• pp.1086-1095
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• 2007

This paper proposes a novel non-coherent TOA estimation scheme using multiple correlation process on the existence of multiple simultaneously operating piconets (SOPs). Impulse radio-ultra wideband (IR-UWB) based on direct sequence spread spectrum (DSSS) using Gold sequence is employed in order to discriminate each piconet. In order to enhance the characteristic of correlation, this paper presents the method of multiple mask operation (MMO). The time of arrival (TOA) of direct line of sight (DLOS) path is estimated via two step coarse/fine timing detection. To verify the performance of proposed scheme, two distinct channel models approved by IEEE 802.15.4a Task Group (TG) are considered. According to the simulation results, it could conclude that the proposed scheme have performed better performance than the conventional method well even in densed indoor multi-path environment as well as in the existence of multiple SOPs.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.1
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• pp.61-66
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• 2005

Location Positioning is a major technology for ubiquitous computing. Recently the research on Location Positioning using UWB is on going. In order to construct an in-door location network, synchronization of base stations is very important. NTP is Popularly used as clock synchronization protocol ranging from LAN to WAN. Also Master-Slave scheme is the simplest method to synchronize in-door network. We compare and analyze NTP and Master-Slave schemes according to the statistical channel model for indoor multipath propagation environment. In this paper, error ranges are calculated at various circumstances that in-door network expands from one primary base station into several base stations. We compared the correctness of NTP and Master-Slave synchronization methods. NTP is more reasonable synchronization protocol in in-door environment.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.18-22
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• 2010

In this paper, we propose and analyze the two way ranging (TWR) positioning technique using ultra wideband (UWB) for indoor environment. We employed IEEE 802.15.3a channel as a simulation environment and used to time of arrival (TOA) algorithm. UWB technology in a low transmission power the less the effect of interfering with the existing system, the frequency can be shared so that it can improve the spectral efficiency. And, positioning technique based on UWB with a very narrow pulse width has high accuracy in indoor environment. From the simulation results, it is analyzed the probability of error and positioning performance for channel effects and confirmed usefulness of the proposed scheme.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.400-405
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• 2018

This paper presents a compact ultra-wideband (UWB) flexible monopole antenna design on a paper substrate. The proposed antenna is made of iterations of a circular slot inside an octagonal metallic patch. This fractal-based geometry has been deployed to achieve compactness along with improved bandwidth, measured reflection coefficient -10 dB bandwidth ranging from 2.7 to 15.8 GHz. The overall size of the antenna is $26mm{\times}19mm{\times}0.5mm$, which makes it a compact one. The substrate used is paper and the main features like environment friendly, flexibility, green electronics applications and low cost of fabrication are the key factors for the proposed antenna. The aforementioned UWB prototype is suitable for many wireless communication systems such as WiMAX, WiFi, RFID and WSN applications. Antenna has been tested for the effect of bending by placing it over a curved surface of a very small radius of 10 mm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.1
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• pp.96-107
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• 2013

In this study, we examine the effect of spreading sequence matched filtering on the power parameters of ultrawideband (UWB) multiuser interference (MUI) under different multiple access (MA) scenarios. More specifically, we investigate the manner in which the length of the sequence MF affects the average power, peak power, and the peak-to-average ratio (PAR) of the matched filtered version of an MUI signal. The results of the analysis performed for a simplified scenario are supported by the simulation results obtained for a realistic multipath environment.