• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.1
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• pp.16-22
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• 2009

This paper aims at designing an impulse-radio ultra-wideband (IR-UWB) transceiver, especially targeting the IEEE 802.15.4a indoor ranging and communication systems. We first investigate the IEEE 802.15.4a IR-UWB signals and suggest the full-digital transceiver architecture accordingly. Since the wireless systems equipped with the impulse signal have the property of low-duty cycle, i.e., discontinuity in time, while the conventional systems takes the continuous signals, it is required to reconfigure the system design, including link budget. Following brief introduction to our IEEE 802.15.4a IR-UWB system hardware, we finally examine the ranging performance in indoor environments to verify our system design.

• Journal of Advanced Navigation Technology
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• v.5 no.2
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• pp.134-140
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• 2001

Ultra Wideband(UWB) system uses wide band signal, which power spectral density likes as a noise floor, so UWB system can be used high speed communication without interfering with other communication system. As this system doesn't use carrier, its structure would be very simple and consume very low power. But conventional UWB system uses Pulse Positioning Modulation(PPM) Method. Therefore it could be to produce discrete power spectrum which decreases system efficiency unintentionally. For eliminating discrete power spectrum and further Euclidean distance, we propose UWB system using Antipodal signal. And we design and simulate antipodal tranceiver using Advanced Design System(ADS).

• Journal of Construction Engineering and Project Management
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• v.6 no.2
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• pp.30-39
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• 2016

This research presents the development of a self-governing mobile robot navigation system for indoor construction applications. This self-governing robot navigation system integrated robot control units, various positioning techniques including a dead-reckoning system, a UWB platform and motion sensors, with a BIM path planner solution. Various algorithms and error correction methods have been tested for all the employed sensors and other components to improve the positioning and navigation capability of the system. The research demonstrated that the path planner utilizing a BIM model as a navigation site map could effectively extract an efficient path for the robot, and could be executed in a real-time application for construction environments. Several navigation strategies with a mobile robot were tested with various combinations of localization sensors including wheel encoders, sonar/infrared/thermal proximity sensors, motion sensors, a digital compass, and UWB. The system successfully demonstrated the ability to plan an efficient path for robot's movement and properly navigate through the planned path to reach the specified destination in a complex indoor construction site. The findings can be adopted to several potential construction or manufacturing applications such as robotic material delivery, inspection, and onsite security.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11C
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• pp.949-954
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• 2008

An ultrawide band (UWB) signal model is proposed to estimate the angle-of-arrivals of the signals arrived in clusters at an UWB receiver for a short-range, high-speed, indoor wireless communication system in an elliptical scattering environment. And a new estimation technique is proposed by modifying the conventional MUSIC algorithm. By using this estimation technique, the estimates of the two unknown parameter sets, angle-of-arrivals and distribution parameters, are obtained with the proposed UWB signal model. The proposed UWB signal model and estimation technique are verified through computer simulations in an ultrawide band communication environment.

• Journal of Advanced Navigation Technology
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• v.10 no.3
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• pp.268-275
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• 2006

The rapid proliferation of in-home and office information applications and services is driving the need for new wireless technologies enabling wideband short range multimedia communications. Due to the growing demand for higher quality media and faster wireless connections, several IEEE standardization groups are considering very high data rate alternatives physical layer(s) for Wireless Personal Area Network (WPAN). The Ultra Wide Band (UWB) multiple access technology based on very narrow pulse transmission, is one viable candidate for these applications providing very high bit rates services, low power consumption and accurate positioning capability. In this paper we provide a methodology to evaluate the UWB system BER performance in UWB wireless fading networks with power controlled UWB devices are considered. Results can be used to analyze the performance of a given network topology and to provide useful design ideas for an UWB home sensor network.

• The Journal of the Korea Contents Association
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• v.9 no.7
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• pp.76-85
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• 2009

UWB signal with high resolution capability can be used to estimate ranging and positioning in wireless personal area network. The node works on its local clock and the frequency differences of nodes have serious affects on ranging algorithms estimating locations of mobile nodes. The low rate UWB, IEEE802.15.4a, describes asynchronous two way ranging methods such as TWR and SDS-TWR working without any additional network synchronization, but the algorithms can not eliminate the effect of clock frequency differences. Therefore, the mechanisms to characterize the crystal difference is essential in typical UWB PHY implementations. In high rate UWB, characterizing of crystal offset with tracking loop is not required. But, detection of the clock frequency offset between the local clock and remote clock can be performed if there is little noise induced jitter. In this paper, we complete related ranging equations of high rate UWB based on TWR with relative frequency offset, and analyze a residual error in the ideal equations. We also evaluate the performance of the relative frequency offset algorithm by simulation and analyze the ranging errors according to the number of TWR to compensate coarse clock resolution. The results show that the relative frequency offset compensation and many times of TWR enhance the performance to converge to a limited ranging errors even with coarse clock resolutions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8A
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• pp.633-643
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• 2003

UWB impulse radio signals have an very short duration, extremely wide bandwidth and share the same frequency spectrum with other existing systems. It was determined by the Federal Communications Commission (FCC) that UWB systems could cause interference with other systems, such as Global Positioning System (GPS) for example. Therefore, at present. the FCC has restricted the use of UWB systems to frequencies above 3.1㎓. In this paper, We evaluated performance of UWB system using proposed pulses in ［1］［2］ that are strictly limited in time to remove interference while, at the same time, contain their power distribution to a frequency band from 3.1㎓ to 10.6㎓. In particular, We evaluated the BER Performance in relation to system parameters such as pulse duration. $\delta$, the number of users. Nu. and the number of symbols, M. We found the optimal pulse duration $\delta$ through computer simulation using developed UWB pulses in ［1］［2］. It is shown that performance evaluation between the UWB communication system using these UWB pulses ［1］［2］and the Gaussian monocycle pulse in M-ary PPM and BPSK schemes. These results can be contributed to construct M-ary PPM UWB communication system in terms of multiuser parameters and pulse duration.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.3049-3051
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• 2005

본 논문은 UWB(Ultra Wide Band) 펄스 기반의 단일 송수신을 통한 근거리 무선측위 시스템 및 방법에 관한 것으로서, UWB 펄스의 높은 시간 분해능을 이용하여 근거리에서 높은 정밀도를 가지고 태그의 위치를 획득할 수 있다. 특히, 마스터-슬레이브 형태로 구성된 비콘(beacon)들 간의 사전 설정을 통해 마스터 비콘과 무선측위 대상인 태그 사이의 단일 송수신만으로 ToA(Time of Arrival) 및 TDoA(Time Difference of Arrival) 기법을 적용할 수 있도록 하며, 이로써 태그의 신호 송신을 최소화하여 태그의 저전력 동작을 가능케하는 UWB기반 단일송수신을 통한 근거리 무선측위 시스템이다.

• Journal of Sensor Science and Technology
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• v.23 no.3
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• pp.149-157
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• 2014

This paper considers the ability of counting and positioning multi-targets by using a mobile UWB radar device. After a background subtraction process, distinguishing between clutters and human body signals, the position of targets will be computed using weighted Gaussian mixture methods. While computer vision offers many advantages, it has limited performance in poor visibility conditions (e.g., at night, haze, fog or smoke). UWB radar can provide a complementary technology for detecting and tracking humans, particularly in poor visibility or through-wall conditions. As we know, for 2D measurement, one method is the use of at least two receiver antennas. Another method is the use of one mobile radar receiver. This paper tried to investigate the position detection of the stationary human body using the movement of one UWB radar module.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.1
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• pp.87-95
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• 2016

Recently, the interests of the precise localization are rapidly increasing, which are linked to IoT(Internet of Things) sensors. The precise localization in indoor environment can be utilized in navigation, security, anti-collision, and various location based services etc. However, conventional positioning sensors, such as PIR, ultrasonic, microwave etc. are vulnerable to weather or insensitive to direction of subject movement or low precision performance. In this paper we implement a UWB-IR localization system for long distance and high-precision localization, which is not affected by temperature, light and weather. The proposed system was divided and designed by H/W, Antenna, S/W parts, each of which was designed based on an accurate analysis and simulation. As a result, we can implemented and verified UWB IR system with precise localization performance.