• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.1
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• pp.9-15
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• 2005

Most of location systems use RF signal. Because multipath is too severe at indoor environment, RF signal are usually used in outdoor positioning such as GPS. To overcome the difficulty at indoor positioning, m positioning is recently developed and is being vigorously studied. Some standardizations on UWB are in progress at IEEE 802.15 committee. In developing UWB positioning system, we should consider the synchronization of sensor network, positioning algorithm, sensor allocation, and so on. This paper presents a comparison of TDOA positioning algorithms that are widely used in location systems. Two algorithms are compared; one is derived by linearization, and the other is by analytic solution(CH algorithm). Simulation results show that the CH algorithm is superior to the linearized least square at indoor environment in that CH algorithm shows consistent positioning performance regardless of the visibility and geometry of basestations.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.34-41
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• 2014

Through applying hostile radar signals that use stagger PRI to PRI transform in real time, we can analyze stagger PRI and calculate the future TOA for active cancellation by using measured TOA and estimated PRI. We shows the effect of the errors that are contained in PRI and measured TOA. Then, it will suggest the technique to improve the accuracy of estimated PRI and the TOA averaging method for reducing the effect of measured TOA error. Finally, we will show that accuracy of estimated future TOA that is calculated by proposed scheme is higher than that of future TOA that is simply calculated with TDOA and newest TOA through comparing RMSE performance.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1467-1468
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• 2006

본 논문에서는 현재 운용되고 있는 낙뢰탐지 시스템들과는 다른 측위방식인 TDOA(Time Difference of Arrival)방법을 사용한 3차원 낙뢰 탐지 및 추적 시스템을 제안한다. TDOA방식은 낙뢰와 수신국사이의 도달시간을 측정하여 두 수신국간의 시간차가 일정한 쌍곡선을 얻고 이들 쌍곡선의 교점을 이용해 낙뢰의 위치를 결정하는 방법이다. 이 시스템을 이용하여 위치정확도가 수 미터인 3차원 낙뢰 방전 궤적을 얻을 수 있다. 시스템의 구현을 위해서 먼저 낙뢰의 신호를 저장해야 하는데, 광대역의 낙뢰신호를 저장하기 위해서는 고속의 디지타이저가 필요하다. 그러나 디지타이저와 프로세서간의 인터페이스의 한계로 연속적으로 이를 저장하는 것은 어려우며, 이러한 신호 저장의 문제점을 해결하기 위해서 낙뢰 신호 저장 시스템이 필요하다. 본 논문에서는 낙뢰의 메커니즘과 광대역 낙뢰신호 검출기법을 설명하고, 구현한 낙뢰 신호 저장 시스템을 소개한다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.10
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• pp.1-8
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• 2000

In this paper, positioning schemes based on AOA(Angle of Arrival), TOA(Time of Arrival), and TDOA(Time Difference of Arrival) measurements are reviewed and analyzed. In the case of using those schemes in microcell structure with severe multipath fading and shadowing conditions, the rapid and unpredictable variation of signal level makes it difficult to estimate the position and velocity of mobiles. Therefore, we propose a novel mobile tracking method based on the multicriteria decision making, in which uncertain parameters such as RSS(Received Signal Strength), the distance between mobile and base station, the moving direction, and the previous location are participated in the decision process using aggregation function in fuzzy set theory. Through a simulation, we analysis the impaction of the frequent change of direction and speed of mobiles.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.2A
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• pp.124-129
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• 2002

We propose a wireless positioning system using IC-IPDL method that exploits the modified-IPDL method and the interference cancellation techniques to improve hearability. In the proposed system, IPDL method is modified to maintain the transmission of CPICH for stability of CDMA network Simultaneously in mobile CPICH is cancelled out using the interference cancellation techniques for improving hearability. The simulation results showed that the proposed location system has a compatible performance to the standard IPDL method though CPICH exists during idle period.

• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.1-8
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• 2013

In the next generation of ATM, ADS-B(Automatic Dependent Surveillance-Broadcast) and multilateration are the main technology recommended by ICAO(International Civil Aviation Organization). However, there are a lot of non-equipped ADS-B aircraft today. Therefore, TIS-B(Traffic Information Service-Broadcast) provides traffic information, which has obtained from radars for non-equipped ADS-B aircraft. In this paper, we presented an onboard multilateration system for non-equipped ADS-B aircraft using SSR(Secondary Surveillance Radar) signal instead of TIS-B. TIS-B has a lot of error because of using radar data, but multilateration has less error than radar because of using TDOA(Time Difference of Arrival) method. Results of performance analysis show that the position accuracy is improved by the proposed method using on-board multilateration.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1128-1135
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• 2010

A wireless positioning system using ultra-wideband (UWB) for indoor wireless positioning uses ranging data in order to accurately estimate location. Commonly, ranging uses time of arrival (TOA), time difference of arrival (TDOA) based on arrival time. The most fundamental issue in the ranging for wireless positioning is to obtain clock synchronization among the sensor nodes and to correct an error caused by the relative clock offset from each node. In this paper, we propose ranging and positioning technique using common clock in order to solve both clock synchronization and clock offset problems. To verify the performance of proposed, we simulated ranging and positioning in channel model introduced by IEEE 802.15.4a Task Group and then results show that location estimation is unaffected by clock offset.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.3
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• pp.74-85
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• 2021

Global Navigation Satellite System (GNSS) receivers are intrinsically vulnerable to radio frequency jamming signals due to the fundamental property of radio navigation systems. A GNSS jamming monitoring system that is capable of jamming detection, classification and localization is essential for infrastructure for autonomous driving systems. For these 3 functionalities, a GNSS jamming monitoring network consisting of a multiple of low-cost GNSS receivers distributed in a certain area is needed, and the precise time synchronizaion between multiple independent GNSS receivers in the network is an essential element. This paper presents a precise time synchronization method based on the direct use of Time Difference of Arrival (TDOA) technique in signal domain. A block interpolation method is additionally incorporated into the method in order to maintain the precision of time synchronization even with the relatively low sampling rate of the received signals for computational efficiency. The feasibility of the proposed approach is verified in the numerical simualtions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.957-960
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• 2006

In this paper, we studied the location estimation algorithm of a spatial 3 dimension which extend the location estimation algorithm of a plane 2 dimension in 2.45GHz band RTLS(Real time location system). We used TDOA scheme which need not a time of transmission information of the tag and estimated 3 dimension coordinates. Also, estimated intersection of hyperbolic curve to X, Y coordinate of the tag at 2D coordinates searching area, $300m\times300m$ and LOS propagation environments. And, we estimated Z coordinate ultimately using X, Y coordinate. The location estimation algorithm of a spatial 3 dimension satisfies the RTLS specification requirement, 3m radius accuracy. From the result, we confirm that the location of tag which similar to actual coordinate in the case to an ideal received offset. However, we verified that the location of tag which escapes from a radius 3m within error range when received offset increased. Therefore, as the future work we are consider enhanced location accuracy of a spatial 3 dimension in RTLS system which using the decrease scheme of reader offset or the discriminate scheme of the estimation location.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.01a
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• pp.91-92
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• 2016

무선 센서 네트워크에서 무선통신기술을 활용한 저비용의 정밀 측위 기술은 교통상황, 의료, 생활정보 등의 다방면에서 활용되고 있다. RSSI를 기반으로 한 측위기법은 TOA, AOA, TDOA에 비해 추가적인 전력 또는 하드웨어가 필요하지 않아 비용 면에서 효율적이다. 하지만 RSSI 값의 패턴은 실제 환경에서 전파방해 요소가 존재하여 작은 움직임에도 크게 변하게 되는 문제점이 있다. 본 논문에서는 RSSI와 IEEE 802.15.4 표준에서 제공되는 정보인 LQI를 이용하여 타겟 노드의 실내 위치를 추정하는 기법을 제안한다. 제안하는 기법을 통해 실제 환경에서 보다 정확한 위치추정을 할 수 있음을 보여준다.