• 산업기술연구
• /
• 제9권
• /
• pp.67-77
• /
• 1989

This study is concerned with the accuracy, the pattern of error with which subjects can interpolate the location of a pointer or a target between two graduation markers with various size on CRT display. Stimuli were graphic images on CRT with a linear, end-marked, ungraduated scales having a target for t base-line sizes. The location of a target is estimated in units over the range 1-99. Smallest error of estimates was at the near ends and middle of the base-line. The median error was less 2 units, modal error was 1, and most error(;99.6%) was within 10. Subjects had a more tendency to overestimate than to underestimate at the left-part of base-line in all siges, and an opposite tendency at the right-part. A proper size to minimize the interpolation error exists such that size 500. It is suggested that interpolation of fifths and even tenths will give a reguired accuracy for certain situations, and relative location and base-line size has a relevant attribute to interpolate.

• 제어로봇시스템학회논문지
• /
• 제21권9호
• /
• pp.898-902
• /
• 2015

Alternative radio-navigation technologies aim at providing continuous navigation solution even if one cannot use GNSS (Global Navigation Satellite System). In shadowing region such as indoor environment, GNSS signal is no longer available and the alternative navigation system should be used together with GNSS to provide seamless positioning. For soldiers in battlefield where GNSS signal is jammed or in street battle, the alternative navigation system should work without positioning infrastructure. Moreover, the radio-navigation system should have scalability as well as high accuracy performance. This paper presents a TWR (Two-Way-Ranging)-based cooperative positioning system (CPS) that does not require location infrastructure. It is assumed that some members of CPS can obtain GNSS-based position and they are called mobile anchors. Other members unable to receive GNSS signal compute their position using TWR measurements with mobile anchors and neighboring members. Error propagation in CPS is analytically studied in this paper. Error budget for TWR measurements is modeled first. Next, location error propagation in CPS is derived in terms of range errors. To represent the location error propagation in the CPS, Location Error Propagation Indicator (LEPI) is proposed in this paper. Simulation results show that location error of tags in CPS is mainly influenced by the number of hops from anchors to the tag to be positioned as well as the network geometry of CPS.

• 대한안전경영과학회지
• /
• 제13권1호
• /
• pp.107-114
• /
• 2011

Location-Based Service(LBS) is a service that provides a variety of convenience in life using location information that can be obtained by mobile communication network or satellite signal. In order to provide LBS precisely and efficiently, we need the location determination technology, platform technology and server technology. In this study, we studied on how we can reduce the error on location determination of objects such people and things. Fingerprint location determination method was applied to this study because it can be used at current wireless communication infrastructure and less influenced by a variety of noisy environment than other location determination methods. We converted the probability value to logarithmic scale value because using the sum of k probability values is not suitable to be applied to weight determination. In order to confirm the performance of suggested method, we developed location determination test program with Visual Basic 6.0 and performed the test. According to indoor and outdoor test results, the suggested stochastic method reduced the distance error by 17%, 18% and 9% respectively at indoor environment and 25%, 11% and 4% at outdoor environment compared with deterministic NN, kNN and kWNN fingerprint methods.

• ETRI Journal
• /
• 제32권5호
• /
• pp.722-728
• /
• 2010

This paper presents the design and fabrication model of a touchpad based on a contact-resistance-type force sensor. The touchpad works as a touch input device, which can sense contact location and contact force simultaneously. The touchpad is 40 mm wide and 40 mm long. The touchpad is fabricated by using a simple screen printing technique. The contact location is evaluated by the calibration setup, which has a load cell and three-axis stages. The location error is approximately 4 mm with respect to x-axis and y-axis directions. The force response of the fabricated touchpad is obtained at three points by loading and unloading of the probe. The touchpad can detect loads from 0 N to 2 N. The touchpad shows a hysteresis error rate of about 11% and uniformity error rate of about 3%.

• 항공우주기술
• /
• 제1권2호
• /
• pp.141-148
• /
• 2002

본 연구는 KOMPSAT-1 EOC 영상의 기하정확도를 향상시키고자 수행되었다. 많은 EOC 영상의 지상위치오차를 분석하였고, 그 오차가 시스템내의 시간 부정확성과 자세데이터의 오차로 인한 것임을 알 수 있었다. 그 개선방안으로 Ancillary 데이터의 시간데이터와 자세데이터를 재구성하였고, 이를 적용하여 영상처리한 결과에서 EOC 영상데이터의 기하정확도가 향상되는 것을 확인하였다.

• 천문학회지
• /
• 제38권4호
• /
• pp.437-443
• /
• 2005

The Solar Radio Burst Locator (SRBL) is a spectrometer that can observe solar microwave bursts over a wide band (0.1-18 GHz) as well as detect the burst locations without interferometry or mechanical scanning. Its prototype has been operated at Owens Valley Radio Observatory (OVRO) since 1998. In this study, we have evaluated the capability of the SRBL system in flux and radio burst location measurements. For this, we consider 130 microwave bursts from 2000 to 2002. The SRBL radio fluxes of 53 events were compared with the fluxes from USAF/RSTN and the burst locations of 25 events were compared with the optical flare locations. From this study, we found: (1) there is a relatively good correlation (r = 0.9) between SRBL flux and RSTN flux; (2) the mean location error is about 8.4 arcmin and the location error (4.7 arcmin) of single source events is much smaller than that (14.9 arcmin) of multiple source events; (3) the minimum location error usually occurred just after the starting time of burst, mostly within 10 seconds; (4) there is a possible anti-correlation (r = -0.4) between the pointing error of SRBL antenna and the location error. The anti-correlation becomes more evident (r=-0.9) for 6 strong single source events associated with X-class flares. Our results show that the flux measurement of SRBL is consistent with that of RSTN, and the mean location error of SRBL is estimated to be about 5 arcmin for single source events.

• 대한전자공학회논문지TC
• /
• 제48권10호
• /
• pp.13-19
• /
• 2011

이 논문은 위성항법시스템을 이용한 위치측위에서 지역별 특성에 따른 위치오차실험을 통하여, 음영지역 발생 원인과 해결 방법을 제안하기 위한 연구이다. 동적측위에서 이동체는 이동 위치에 따라 사용할 수 있는 위성항법시스템의 수가 변화한다. 정확한 위치측위를 위해서는 4개 이상의 위성항법시스템으로부터 위치정보데이터를 수신 받아야 한다. 하지만 급격한 산업화와 열악한 지역 환경으로 위치오차가 커지고 음영지역이 발생한다. 이러한 위치오차를 줄이고 음영지역 발생을 해소하기 위해서는 대도시의 환경과 지역 환경 특성에 따른 원인을 파악하는 것이 중요하다. 따라서 본 논문에서는 대도시, 주택 지역, 숲 지역, 바다 지역, 대지 등을 선정하여 위치오차와 음영지역 발생 원인을 실험하였다. 그리고 이 논문을 기반으로 지역 환경에 따른 적합한 고정밀 측위 알고리즘을 제안하고, 음영지역해소 알고리즘을 제안하려고 한다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.58-58
• /
• 2001

This paper shows a practical approach that is robust to the errors causing path-delay in mobile wireless location, and analyzes its performance by comparing with other methods. NLOS(non-line-of-sight) error and multipath are two big sources of positioning error in wireless location. Contrary to GPS(global positioning system), they result from the terrestrial propagation of a signal. Especially, since LOS(line-of-sight) path between a transceiver and a receiver is blocked by intermediate buildings and topography, NLOS causes a signal to be reflected and diffracted. This path-delay error is very localized, and so, it is not easy to be estimated and mitigated. To treat such localized error, therefore ...

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
• /
• pp.606-608
• /
• 2005

In this paper, we introduce localization server system calculated real location of objects using raw data of location-awareness from sensor node gateway. The software architecture of localization server system consists of location calculation and actuator control based on location. Also, this system supports for collecting raw data, calculating location of real objects using raw data, correcting error from outer environment, and server for applications based on location.

• 대한원격탐사학회지
• /
• 제27권2호
• /
• pp.99-105
• /
• 2011

정지궤도 기상위성자료의 시차오류(Parallax error)는 기상위성 산출물 중에서 구름과 관련된 산출물의 위치 오류를 발생시키기 때문에 강수의 유무와 강도를 옳게 분석하더라도 강수위치 선정에 오류를 발생시킬 수 있다. 본 연구에서는 시차오류를 보정하는 방법을 제시하고 보정방법을 검증 및 적용하는데 목적이 있다. 시차오류에 의한 구름위치 보정은 첫째, 원래의 위성친정각파 구름고도를 입력 자료로 보정된 위성천정각을 산출한다. 둘째, 보정된 위성천정각과 위성방위각을 이용하여 위성시차오류를 보정하여 구름의 원래 위치에 가깝게 옮겨준다. 시차오류는 위성천정각이 증가하고 구름고도가 증가 할수록 더 크게 나타나며, 동아시아지역($20{\sim}50^{\circ}N$)에서는 최대 약 25km의 구름위치오류가 발생 할 수 있다. Terra MODIS(Moderate-Resolution Imaging Spectrometer)의 센서천정각 $20^{\circ}$이내의 관측 자료와 검증한 결과 시차 보정된 구름위치가 원래 위치에 가깝게 개선된 것을 확인 할 수 있었다. 본 논문에서 제시한 정지위성 시차오류 보정방법은 향후 아시아지역의 여러 정지궤도 기상위성의 영상 활용성 증대에도 기여할 것이다.