Orbit Ephemeris Failure Detection in a GNSS Regional Application

Ahn, Jongsun,Lee, Young Jae,Won, Dae Hee,Jun, Hyang-Sig,Yeom, Chanhong,Sung, Sangkyung,Lee, Jeong-Oog The Korean Society for Aeronautical and Space Scie 2015 International Journal of Aeronautical and Space Sc Vol.16 No.1

To satisfy civil aviation requirements using the Global Navigation Satellite System (GNSS), it is important to guarantee system integrity. In this work, we propose a fault detection algorithm for GNSS ephemeris anomalies. The basic principle concerns baseline length estimation with GNSS measurements (pseudorange, broadcasted ephemerides). The estimated baseline length is subtracted from the true baseline length, computed using the exact surveyed ground antenna positions. If this subtracted value differs by more than a given threshold, this indicates that an ephemeris anomaly has been detected. This algorithm is suitable for detecting Type A ephemeris failure, and more advantageous for use with multiple stations with various long baseline vectors. The principles of the algorithm, sensitivity analysis, minimum detectable error (MDE), and protection level derivation are described and we verify the sensitivity analysis and algorithm availability based on real GPS data in Korea. Consequently, this algorithm is appropriate for GNSS regional implementation.

B-Value를 이용한 GBAS 지상국 오차 표준편차 모델 개발 및 성능 평가

전향식(Hyang-Sig Jun),안종선(Jong-sun Ahn),이영재(Young-Jae Lee),최영규(Young-kiu Choi),성상경(Sang-Kyung Sung),염찬홍(Chan-Hong Yeom) 한국항공우주학회 2009 韓國航空宇宙學會誌 Vol.37 No.12

국제민간항공기구 및 미 연방항공청에서는 항공기 이?착륙에 적용될 수 있는 지역위성항법보강시스템 (GBAS)에 대한 연구 개발을 수행하고 있다. 항공기 이?착륙에 위성항법시스템이 사용되는 만큼 시스템에 대한 무결성 확보가 최우선시 되어야 한다. 이를 위해 GBAS에서는 발생 가능성이 있는 오차 모델을 통해 위치 오차 예측값을 계산하고 이를 허용 한계치를 초과 하는 지 확인하고, 만약 초과하였을 경우 항공기는 GBAS 시스템 활용을 중단하고 다른 항법수단을 강구하게 된다. 하지만 높은 위치 오차 예측값은 시스템의 무결성 확보에는 도움이 되겠지만, 가용성 확보에 어려움이 있다. 본 논문에서는 제주도 국제공항에 설치되어 있는 항공우주연구원 GBAS 기준국의 실제 데이터를 사용하여, 위치 오차 예측값 계산에 사용될 수 있는 B-Value 기반의 지상국 오차 표준편차 모델 제시하였다. 또한 제시된 오차 표준편차 모델에 시그마 인플레이션을 적용하여 GBAS의 가용성 향상을 검증하였다. The ICAO and FAA are developing and verifying of GBAS for civil aircraft landing and take-off. The guarantee of aircraft integrity issue is the important part of GBAS. To guarantee integrity, the GBAS ground facility broadcasts various informations to aircraft. The informations are related to the estimated accuracy of each pseudorange correction and the estimated error terms, for example B-value and standard deviation of the ground facility error. These parameters are used to calculate position error (estimated value of the user). If estimated position errors don't satisfy requirements, aircraft use alternate navigation means. In this paper, GBAS reference stations's real data, which operated by KARI (Korea Aerospace Research Institute) in Jeju international airport, are used to development of new ground facility error standard deviation model. We verify improvement of GBAS availability , with respected to vertical protection level, using B-value based a new ground facility error standard deviation model and a sigma inflation factor.

Orbit Ephemeris Failure Detection in a GNSS Regional Application

Jongsun Ahn,Young Jae Lee,Dae Hee Won,Hyang-Sig Jun,Chanhong Yeom,Sangkyung Sung,Jeong-Oog Lee 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.1

To satisfy civil aviation requirements using the Global Navigation Satellite System (GNSS), it is important to guarantee system integrity. In this work, we propose a fault detection algorithm for GNSS ephemeris anomalies. The basic principle concerns baseline length estimation with GNSS measurements (pseudorange, broadcasted ephemerides). The estimated baseline length is subtracted from the true baseline length, computed using the exact surveyed ground antenna positions. If this subtracted value differs by more than a given threshold, this indicates that an ephemeris anomaly has been detected. This algorithm is suitable for detecting Type A ephemeris failure, and more advantageous for use with multiple stations with various long baseline vectors. The principles of the algorithm, sensitivity analysis, minimum detectable error (MDE), and protection level derivation are described and we verify the sensitivity analysis and algorithm availability based on real GPS data in Korea. Consequently, this algorithm is appropriate for GNSS regional implementation.

소량의 쌀 시료로 신속한 식미 관능평가를 위한 컵 배열 순위법

이점식(Jeom-Sig Lee),곽지은(Jieun Kwak),윤미라(Mi-Ra Yoon),이정희(Jeong-Heui Lee),안억근(Eok-Keun Ahn),박향미(Hyang-Mee Park),원용재(Yong-Jae Won),손지영(Ji Young Shon),김준환(Jun Hwan Kim),서정필(Jung-Pil Suh),천아름(Areum-Chun),전재범 한국육종학회 2015 한국육종학회지 Vol.47 No.2

Rice breeders or sensory evaluators are striving to develop the rapid and correct sensory evaluation method of the cooked rice with a small-sample. This study was conducted to develop a method of cooking condition and sensory evaluation of the cooked rice rapidly and correctly with a small-sample by introducing a concept of arrangement ranking to the conventional sensory evaluation method by cooking in the cup, which has been used only as a simple test. A method of simultaneous cooking of the five samples for one round of test was developed. And, an arrangement ranking method was developed just like stacking a tower by arranging the cups in the sensory evaluation. The proposed method was named as cup arrangement ranking method. The correlation analysis between the cup arrangement ranking method (CARM) and the standard sensory evaluation method(SSEM) showed a high significance of correlation (r=0.83**∼0.91**, ‘13∼’14). Further, when effectiveness of proposed method was compared with the standard sensory evaluation method, the sample quantity was a 30g level for one round of test, which is a tenth of SSEM. The time consumed for sensory evaluation was two minutes per one sample, which was a reduced value by half as compared with the time consumption by SSEM. Therefore, the cup arrangement ranking is expected to be an effective method in the selection of excellent rice line or variety having good taste by evaluating the cooking quality rapidly with a small-sample in early generation.

반송파 측정값 기반 GNSS 궤도력 고장 검출 알고리즘 성능 분석

안종선(Jongsun Ahn),전향식(Hyang-Sig Jun),남기욱(Gi-Wook Nam),염찬홍(Chan-Hong Yeom),이영재(Young Jae Lee),성상경(Sangkyung Sung) 한국항공우주학회 2014 韓國航空宇宙學會誌 Vol.42 No.6

본 논문에서는 위성항법시스템의 무결성 저해 요인 중, 항법메시지에 담겨 전송되는 궤도력 (Ephemeris) 정보의 고장 여부를 판단할 수 있는 알고리즘을 분석 및 성능 평가를 수행하였다. 알고리즘은 반송파 측정값과 두 지상 기준국간의 기저벡터 정보가 활용된다. 주요 특징으로 기준국 기저선과 위성이 이루는 기하학적 조건 기저선 길이에 따라 동일 궤도력 고장에 대해 알고리즘의 성능의 편차가 발생할 수 있음을 확인하였다. 또한 알고리즘 적용이 적합한 GBAS의 지상 기준국 안테나 배치 방안 및 제주국제공항에 운용되었을 때의 한계치 및 성능 지표 (MDE : Minimum Detectable Error)를 계산하였다. We analyze fault detection algorithm of ephemeris included in navigation message, which is one of the GNSS risk factors. This algorithm uses carrier-phase measurement and baseline vector of two reference stations and is alternative method for uncertainty condition of previous ephemeris. Even though same ephemeris fault is occurred, the geometry condition, between baseline vector of reference stations and satellites, effects on performance of algorithm. Also, we introduce the suitable geometry of reference stations, threshold and performance index (MDE : Minimum Detectable Error) in jeju international airport

중만생 복합내병 다수성 발아현미용 거대배아미 ‘큰품’

안억근(Eok-Keun Ahn),현웅조(Ung-Jo Hyun),정국현(Kuk-Hyun Jung),원용재(Yong-Jae Won),홍하철(Ha-Cheol Hong),박향미(Hyang-Mi Park),장재기(Jae-Ki Chang),이정희(Jeong-Heui Lee),이점호(Jeom-Ho Lee),성낙식(Nak-Sig Sung),서정필(Jung-Pil Suh) 한국육종학회 2021 한국육종학회지 Vol.53 No.4

‘Keunpum’ is a mid-late maturing, high yielding, giant embryo rice (Oryza sativa L.) cultivar which is adapted to central plainsand was developed to be used as (germinated) brown rice. It is resistant to multiple diseases with a good grain quality. This cultivar wasderived by crossing a giant embryo rice variety ‘Keunnun’ and a mid-late maturing, multi-disease resistant rice cultivar ‘Samkwang’-it hasgood palatability of cooked rice. The growth period of this cultivar is approximately 117 d from seeding to heading, with a culm lengthof 88 ㎝, panicle length of 20 ㎝, 13 panicles per hill, 136 spikelets per panicle, and 1,000-grain weight of 19.1 g brown rice. This varietyhas low tolerance to cold stress and premature germination similar to ‘Keunnun’ but exhibits high resistance to lodging. In addition, ‘Keunpum’is resistant to bacterial blight (race K1, K2, K3), rice stripe virus, and is moderately resistant to leaf and neck blast. Its average milled riceyield for three years reached 5.34 MT/ha, which is 10% higher than that of ‘Keunnun’. In the brown and germinated brown rice of thiscultivar, the total dietary fiber content are 6.45% and 6.71%, and the GABA (γ-amino butyric acid) content are 6.61 and 39.47 mg/100g, respectively. In addition, the total contents of polyphenol, flavonoid, and tannin were higher in ‘Keunpum’ brown rice than in ‘Keunnun’. The DPPH and ABTS radical scavenging activities were 75.23, 116.08 mg TE/100g, respectively. These functional components and antioxidantactivities play an important role in inhibiting diseases and the aging process of the human body. Therefore, it is expected to be used asa basic data in the manufacture of secondary processed products using germinated brown rice (Grant No. 7684).

돌나무의 가을 삽목번식에 미치는 삽목용토 및 시기의 영향

안정호(Jeong Ho Ahn),최성식(Seong Sig Choe),배종향(Jong Hyang Bae),이승엽(Seung Yeob Lee) (사)한국생물환경조절학회 2007 생물환경조절학회지 Vol.16 No.2

돌나물의 가을 삽목번식을 위한 적정 삽목용토와 삽목시기를 조사하기 위하여, 농가에서 손쉽게 구할 수 있는 밭흙, 강모래와 훈탄을 혼합한 삽목용토의 효과를 조사하였다. 밭흙과 모래를 1:1 또는 2:1 (v/v)로 혼합하여 사용하는 것이 활착, 지상부 생육 및 뿌리발달이 양호하여 경제적이었다. 선발된 삽목용토(밭흙:모래 =2:1)를 이용하여 10×5 ㎝ 간격으로 가을 노지삽목을 실시한 결과, 9월 초중순에 히는 것이 뿌리 및 지상부 생육이 양호하고, 월동전 충분한 rosette를 확보할 수 있어 안정적이었다. 따라서 가을 노지삽목 한계기는 9월 20일로서, 삽목시기가 늦을 경우, 이듬해 봄철 적정 수량을 확보를 위하여 삽수의 수량을 25-30% 늘려 밀식재배하는 것이 바람직하다. For autumn cutting of Sedum sarmentosum, the influences of bedsoil and cutting date were investigated. Among six kinds of bedsoils mixed upland soil, carbonized rice and sand, the mixture with upland soil and sand (1:1 and 2:1, v/v) showed excellent root and shoot growth. The mixtures with upland soil and carbonized rice were lower rooting than the mixture with upland soil and sand. In field condition, autumn cutting was conducted with 10×5 ㎝ space using the mixture with upland soil and sand (2:1, v/v) at intervals of 10 days from September 1 to October 10. Both root and shoot growth were significantly decreased by delayed date. In cutting from early to middle September, root and shoot growth, and number of rosette before wintering were desirable for shoot production next spring. The safety date to autumn cutting before wintering was on September 20 in field condition. If autumn cutting is late than September 20, the number of scion has increased 25 - 30% to secure a full rosette before wintering. The results could provide the beneficial information for cutting propagation of S. sarmentosum under field condition in autumn.

비공통오차 증가로 인한 위성항법보강시스템 위치 오차 분산 변화 분석

전향식,안종선,염찬홍,이영재,최영규,Jun, Hyang-Sig,Ahn, Jong-Sun,Yeom, Chan-Hong,Lee, Young-Jae,Choi, Young-Kiu 한국정보통신학회 2008 한국정보통신학회논문지 Vol.12 No.6

위성항법보강시스템은 위성항법시스템 (GNSS : Global Navigation Satellite System)의 측정값에 오차 성분을 제거하여 정밀한 항법 정보를 제공한다. 하지만 기준국과 이동국 사이의 공통오차(전리층 지연, 대류층지연, 위성 시계오차, 궤도력 오차)는 제거할 수 있지만 전리층, 대류층, 신호잡음 등에 의해 발생하는 노이즈 성분의 비공통 오차는 제거 할 수 없다. 비공통오차는 항법정보의 오차를 발생하여, 항공기가 잘못된 위치 정보를 사용할 수 있으며, 특히 이 착륙시에 잘못된 항법정보는 항공기 안전에 심각한 영향을 미치게 된다. 본 논문에서는 다중 기준국을 사용하여 유동적인 전리층 및 대류층 습윤 증기량에 따라 비공통오차의 증가를 위치 오차 분산 변화를 통해 확인하였다. A GNSS augmentation system provides precision information using corrected GNSS pseudorange measurements. Common bias errors are corrected by PRC (Pseudorange Correction) between reference stations and a rover. However non-common errors (ionospheric and tropospheric noise error) are not corrected. Using position error variance this paper analyzes non-common error (noise errors) of ionosphere and troposphere wet vapor.

항공기 탑재용 GNSS 수신기 고장검출 알고리즘 및 운용범위 연구

노형태(Hyungtae Nho),안종선(Jongsun Ahn),성상경(Sangkyung Sung),전향식(Hyang-Sig Jun),염찬홍(Chan-Hong Yeom),이영재(Young Jae Lee) 한국항공우주학회 2012 韓國航空宇宙學會誌 Vol.40 No.2

본 논문에서는 항공기 탑재용 GNSS 수신기 고장검출 알고리즘과 운용범위를 제안하였다. 고장난 항공기 수신기는 항공기에서 계산한 보정정보를 주변 항공기간 상호 교환 후에, 보정정보 일치 여부를 통해 검출한다. 이를 위해, 항공기 수신기 고장검출 알고리즘에 사용되는 검정통계량으로 보정정보 잔차값을 사용하였으며, 운용범위는 지상 기준국을 중심으로 거리에 따른 DGPS 위치오차 증가량을 이용하여 설정하였다. 정확한 고장검출을 위해 운용범위 안의 항공기들만을 사용하여 항공기 탑재용 GNSS 수신기 고장검출을 시도하는 방안을 제안하였다. In this paper, we proposed a algorithm and an operation boundary for fault detection of a onboard GNSS receiver. After aircraft exchange corrections computed by an aircraft receiver, a faulty aircraft receiver is detected by checking consistency of correction. For this purpose, PRC residual is used as the test statistic for fault detection of the onboard GNSS receiver. And operation boundaries are set by using DGPS position error increase with respect to the distance from a reference station. If the fault detection is performed by using aircraft only in operation boundary, the more accurate fault detection can be possible.

위성 앙각별 시그마 팽창계수 분석을 통한 GBAS 가용성 향상

박종근(Jong-Geun Park),안종선(Jongsun Ahn),전향식(Hyang-Sig Jun),염찬홍(Chan-Hong Yeom),성상경(Sangkyung Sung),이영재(Young Jae Lee) 한국항공우주학회 2014 韓國航空宇宙學會誌 Vol.42 No.5

지역기반 위성항법보강시스템 (GBAS : Ground Based Augmentation System)은 환경적인 요인에 많은 영향을 받기 때문에 설치 운영될 지역의 환경 요인 분석이 중요하다. 본 연구는 위성 앙각을 고려한 B-Value의 시그마 팽창을 제안하여 대립가설의 VPL (Vertical Protection Level) 성능을 분석하였다. 또한 해당지역의 환경조건을 만족하는 데이터를 수집하여 위성앙각 5° 간격의 시그마 팽창계수를 산출하였다. 산출된 결과는 위성앙각에 따라 커브피팅을 통해 함수화하여, 실험지역의 환경조건 (태양활동, 습윤 지연)에 알맞은 시그마 팽창을 제안하였다. 위성 앙각에 따른 시그마 팽창계수 분석결과 습윤 지연에 의한 영향은 미미했으나, 태양활동에 의한 영향은 태양활동이 활발할수록 시그마 팽창계수가 증가하는 것을 확인할 수 있었다. 또한, 위성 앙각을 고려한 시그마 팽창 계수의 적용으로, 기존 방법 대비 무결성 뿐만 아니라 고앙각 위성에서의 불필요한 마진 제거가 가능하여 가용성이 향상됨을 확인할 수 있었다. The Ground Based Augmentation System (GBAS) is influenced by environmental factors, making analysis in the installation region important. This study has proposed the sigma inflation of the B-value considering the satellite elevation angle and analyzed the Vertical Protection Level (VPL) of the H1 hypothesis. After collecting data that meet the environmental conditions of the installation region, sigma expansion coefficients by the unit of satellite elevation angle (5°) have been estimated. The obtained results were functionalized through curve-fitting, and sigma inflation customized for the environmental conditions of the test region was proposed. Then, the characteristics were classified and analyzed depending on humidity and solar activities. According to the sigma inflation with respect to elevation angle analysis, changes in the size of sigma inflation factors by the difference of humidity were minor. However, the VPL under the satellite elevation angle-based sigma inflation met integrity. Also, considering the sigma inflation factor with respect to elevation angle, compared to existing methods, high-integrity and improved availability is confirmed by removing unnecessary margins in high elevation angle satellite.