• Title/Summary/Keyword: Single station

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Performance Expectation of Single Station PPP-RTK using Dual-frequency GPS Measurement in Korea

  • Ong, Junho;Park, Sul Gee;Park, Sang Hyun;Park, Chansik
    • Journal of Positioning, Navigation, and Timing
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    • v.10 no.3
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    • pp.159-168
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    • 2021
  • Precise Point Positioning-Real Time Kinematic (PPP-RTK) is an improved PPP method that provides the user receiver with satellite code and phase bias correction information in addition to the satellite orbit and clock, thus enabling single-receiver ambiguity resolution. Single station PPP-RTK concept is special case of PPP-RTK in that corrections are computed, instead of a network, by only one single GNSS receiver. This study is performed to experimentally verify the positioning accuracy performance of single baseline RTK level by a user who utilizes correction for a single station PPP-RTK using dual frequencies. As an experimental result, the horizontal and vertical 95% accuracy was 2.2 cm, 4.4 cm, respectively, which verify the same performance as the single baseline RTK.

Orbit Determination Accuracy Improvement for Geostationary Satellite with Single Station Antenna Tracking Data

  • Hwang, Yoo-La;Lee, Byoung-Sun;Kim, Hae-Yeon;Kim, Hae-Dong;Kim, Jae-Hoon
    • ETRI Journal
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    • v.30 no.6
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    • pp.774-782
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    • 2008
  • An operational orbit determination (OD) and prediction system for the geostationary Communication, Ocean, and Meteorological Satellite (COMS) mission requires accurate satellite positioning knowledge to accomplish image navigation registration on the ground. Ranging and tracking data from a single ground station is used for COMS OD in normal operation. However, the orbital longitude of the COMS is so close to that of satellite tracking sites that geometric singularity affects observability. A method to solve the azimuth bias of a single station in singularity is to periodically apply an estimated azimuth bias using the ranging and tracking data of two stations. Velocity increments of a wheel off-loading maneuver which is performed twice a day are fixed by planned values without considering maneuver efficiency during OD. Using only single-station data with the correction of the azimuth bias, OD can achieve three-sigma position accuracy on the order of 1.5 km root-sum-square.

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A Case Study of SIL Analysis for Single Station Controller in Nuclear Power Plant Based on IEC 61508 (IEC 61508에 기반한 원자력 발전소용 안전 등급 제어기의 SIL 분석에 대한 사례연구)

  • Kim, Gun Myung
    • Journal of Applied Reliability
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    • v.16 no.3
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    • pp.231-237
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    • 2016
  • Purpose: It is not easy to suggest a quantitative data related to safety analysis. The objective of this paper is to propose a method of Safety Integrity Level (SIL) analysis and to suggest a SIL analysis result for single station controller in nuclear power plant based on IEC 61508. Methods: The Failure Modes and Effects Diagnostic Analysis (FMEDA) and average probability of failure on demand (PFD) are used for SIL assessment. Results: A SIL of single station controller is evaluated 4 by a reliability analysis results and PFD. Conclusion: A SIL analysis method and result for single station controller based on IEC 61508 are proposed in this paper. It can applicable for a manufacturer data in safety-related system.

ANGLES ONLY ORBIT DETERMINATION FROM SINGLE TRACKING STATION

  • Lee Byoung-Sun;Hwang Yoola
    • Bulletin of the Korean Space Science Society
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    • 2004.10b
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    • pp.304-307
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    • 2004
  • Satellite orbit determination using angles only data from single ground station is carried out. The KOMPSAT-1 satellite mono-pulse angle tracking data from 9-meter S-band antenna at KARI site in Daejeon are used for the orbit determination. Various angle tracking arcs from one-day to five-day are processed and the orbit determination results are analyzed. Antenna pointing data are predicted based on the orbit determination results to check the possibility of re-acquisition and tracking of the satellite signal. Normal satellite mission operations including orbit determination, antenna prediction, satellite re-acquisition and automatic tracking from predicted antenna angle pointing data are concluded to be possible when three-day angle tracking data from single tracking station are used for the orbit determination.

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Traffic analysis of the CDMA base station with repeaters using time delay devices (CDMA 시스템에서 Time Delay를 이용한 기지국과 중계기 Traffic 분석)

  • 조웅호;진용옥
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.9A
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    • pp.1348-1358
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    • 2000
  • The paper contributes to a traffic analysis for the CDMA cellular base station with repeater which are operated in a cell site. Usually the repeaters' traffic of the CDMA cellular system hardly could be separated from that of the base station because the links of the repeaters are divided from RF circuits of the base station. The paper introduces a traffic measuring method that separates the traffic of repeaters from that of the base station using time delay device. To get general results we use a single BTS(Base station Transceiver Subsystem) with three repeater as well as a single BTS with a single repeater. Then we proved that the traffic of the repeaters could separate from that of the base station clearly.

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Single-Fiber Bidirectional Transmission System Using Base Station Without Light Sources (광원이 없는 Base Station을 이용한 단일 광섬유 양방향 전송 시스템)

  • 전금수;정용채;임명섭;반재경
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.5A
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    • pp.323-332
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    • 2003
  • We have proposed and implemented a novel cost-effective optical subcarrier mutiplexing transceiver for base station without light sources in which optical signal can be transmitted bidirectionally over a single optical fiber. Modulated optical signal is retransmitted from the base station to the central office using a ring-type base station which consists of a circulator and an Mach-Zehnder modulator, where the optical source is supplied from the central office. In order to investigate the feasibility of the proposed base station without light sources, we have measured adjacent channel power ratio and carrier to noise ratio by transmitting the IS-95 CDMA signal and 14 tones carrier signal bidirectionally through the system.

Improvement of Relative Positioning Accuracy with GPS Carrier Phase Using Multi-Base Station (다중기준국 방식을 이용한 GPS 반송파 상대측위 정확도 향상)

  • Lee, Jae-One
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.26 no.6
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    • pp.617-624
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    • 2008
  • In general, RTK-GPS(Real Time Kinematic GPS) based on the single reference station is able to determinate the high accurate position of rover on the spot using error correction information of transmitted carrier phase from the base station via wireless modem. However, single reference station method has some weak points to decrease positioning accuracy because it must be obtained carrier phase from the each satellite continuously, allowed to transmit without obstacle and limited to short base line distance between base and rover station. This paper aims to attempt network based GPS carrier phase differential positioning using three multi reference stations to overcome the method of single reference station and RTK network is realized by real time monitoring program with Visual C++. The optimum error correction value of three multi reference stations by RTK networking is selected automatically to correct the position of rover station. In this paper, this algorithm is applied to determine sea water level using GPS buoy, and the accuracy results of water level change were analyzed and compared with each other using single and multi reference stations.

A field survey on roof ventilation system of single-span plastic greenhouse in cucurbitaceae vegetable cultivation (박과작물 재배 단동 비닐하우스의 천장 환기시스템 설치 실태조사)

  • Yeo, Kyung-Hwan;Yu, In-Ho;Rhee, Han-Cheol;Cheong, Jae-Woan;Choi, Gyeong Lee
    • Korean Journal of Agricultural Science
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    • v.40 no.4
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    • pp.317-323
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    • 2013
  • This research was conducted to obtain the basic information for establishment of standard guidelines in the design and installation of roof ventilation system in single-span plastic greenhouse. To achieve this, the greenhouse structure & characteristics, cultivation status, and ventilation system were investigated for single-span greenhouse with roof ventilation system cultivating the Cucurbitaceae vegetables, watermelon, cucumber, and oriental melon. Most of single-span watermelon greenhouse in Haman and Buyeo area were a hoop-style and the ventilation system in those greenhouses mostly consisted of two different types of 'roof vent (circular or chimney type) + side vent (hole) + fan' and 'roof vent (circular type) + side vent (hole or roll-up type)'. The diameter of circular and chimney-type vent was mostly 60cm and the average number of vents was 10.5 per a bay with vent spacing of average 6.75m. The ratio of roof vent area to floor area and side vent area in the single-span watermelon greenhouse with ventilation fan were 0.46% and 7.6%, respectively. The single-span cucumber greenhouse in Haman and Changnyeong area were a gable roof type, such as even span, half span, three quarter and the 70.6% of total investigated single-span greenhouses was equipped with a roof ventilation fan while 58.8% had a circulation fan inside the greenhouse. The ratios of roof vent area to floor area in the single-span cucumber greenhouse ranged from 0.61 to 0.96% and in the case of the square roof vent, were higher than that of the circular type vent. On average, the roof ventilation fan in single-span cucumber greenhouse was equipped with the power input of 210W and maximum air volume of $85.0m^3/min$, and the number of fans was 9.75 per a bay. The number of roof vent of single-span oriental melon greenhouse with only roll-up type side vent ranged from 8 to 21 (average 14.8), which was higher than that of other Cucurbitaceae vegetables while the vent number of the greenhouse with a roof ventilation fan was average 7 per a bay.