http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
GPS L1/L2C/L4 수신기를 위한 적응 코드추적루프 설계
최헌호(Heon Ho Choi),임덕원(Deok Won Lim),이상욱(Sanguk Lee),김지훈(Ji-Hoon Kim),이상정(Sang Jeong Lee) 제어로봇시스템학회 2011 제어·로봇·시스템학회 논문지 Vol.17 No.3
In this paper, an adaptive signal tracking loop for a GPS L1/L2C/L5 receiver is designed. The design parameters is adjusted according to the receiver"s operating conditions such as the signal strength and the receiver dynamics by using the different characteristics of GPS L1, L2C and L5 signal. Simulation results show that the tracking accuracy of the proposed signal tracking loop is better than those of L1, L2C and L5 only tracking loop.
항행 및 항법 분야 : 전파위협원 위치결정을 위한 TDOA/AOA 기반의 DOA 추정 기법 연구
최헌호 ( Heon Ho Choi ),진미현 ( Mi Hyun Jin ),임덕원 ( Deok Won Lim ),남기욱 ( Gi Wook Nam ),박찬식 ( Chan Sik Park ),이상정 ( Sang Jeong Lee ) 한국항행학회 2011 韓國航行學會論文誌 Vol.15 No.6
본 논문에서는 GBAS 환경에서 전파위협원 위치 결정을 위한 TDOA/AOA 기반의 효과적인 DOA 추정 기법을 제안한다. TDOA 측정치만을 이용하여 추정한 1차 근사해와 DOP를 이용하여 DOA 추정 범위를 현저하게 감소시킴으로써 효과적으로 전파위협 신호의 DOA를 추정할 수 있다. 제안한 기법을 통하여 비슷한 연산량으로 더 높은 DOA 정밀도를 얻을 수 있으며, 동시에 전파위협원 위치 추정 정확도를 높일 수 있다. 또한 소프트웨어 기반의 시뮬레이션을 통하여 제안한 기법의 성능을 검증하였다. This paper proposes the DOA estimation method based on TDOA/AOA for jammer localization method in GBAS environment. The proposed method can effectively estimate DOA of jamming signal as the range for DOA estimation is reduced remarkably by using DOP and 1st approximate solution using TDOA measurements only. Through the proposed method, more precise DOA can be obtained and the performance of jammer localization is increased simultaneously. Also, the effectiveness of proposed method will be confirmed through the simulated results.
상대항법 성능 분석 플랫폼 개발 및 이를 이용한 성능 개선
최헌호(Heon Ho Choi),심우성(Woo Seong Shim),조성룡(SungLyong Cho),한영훈(Young Hoon Han),박찬식(Chansik Park),이상정(Sang Jeong Lee) 제어로봇시스템학회 2012 제어·로봇·시스템학회 논문지 Vol.18 No.5
The positions of vessels in JTIDS where each vessel broadcasts its position, can be found using the relative navigation method. Besides positioning, the relative navigation could be adopted for identification friend or foe, tracking targets, monitoring battle field and etc. In this paper, we have explained the fundamental operation and technical structure for the relative navigation and implemented the simulation platform to evaluate the basic function and performance of the system in arbitrary environment. Using platform, the availability of relative navigation within the group network and the characteristic of the algorithm for position prediction was verified. Based on the simulation result, it was verified that EKP based navigation algorithm could produce great initial error and need quite convergence time. To improve the performance, we proposed a new navigation algorithm which uses the minimum norm estimation algorithm until the EKF converges. The simulation results reveal the relative navigation can be effectively used in the formation flight and collision avoidance system.
GPS 수신기를 위한 모델 기반 다중경로 신호 추정 기법
임덕원(Deok Won Lim),최헌호(Heon Ho Choi),허문범(Moon Beom Heo),이상정(Sang Jeong Lee) 제어로봇시스템학회 2012 제어·로봇·시스템학회 논문지 Vol.18 No.4
Multipath remains a dominant source of ranging errors in GNSS (Global Navigation Satellite System). And it is generally considered undesirable in the context of GNSS, since the reception of multipath can make significant distortion to the shape of the correlation function. In this paper, therefore, the model of the distorted shape of the correlation function is formulated and a MBME (Model-Based Multipath Estimation) technique for GPS L1/L5 receivers is proposed in order to estimate the parameters of the indirect signal such as the amplitude and the delay. The MBME technique does not require the any hardware modifications and it can estimate the parameters for both the short and long-delay multipath. Especially, it would be the very effective technique for the short-delay multipath if the L5 signal is available. Finally, the feasibility of the proposed technique has been confirmed by simulation results.
최윤섭(Yun Sub Choi),진미현(Mi Hyun Jin),최헌호(Heon Ho Choi),이상정(Sang Jeong Lee),박찬식(Chansik Park) 한국통신학회 2012 韓國通信學會論文誌 Vol.37 No.11(융합기술)
GNSS의 재밍에 대응하는 기법은 입사되는 재밍 전력을 억제하는 항재밍 기법과 재밍신호원의 위치를 찾아내는 재머위치결정 기법이 주로 사용된다. 두 방법 모두 재밍신호의 방향을 탐지해야 하며 일반적으로 대표적인 도래각 결정알고리즘인 MUSIC이 사용된다. 그러나 MUSIC은 높은 분해능을 가짐에도 불구하고 모든 후보각에 대한 검색을 수행하므로 검색시간이 길다는 단점이 있다. 본 논문에서는 MUSIC의 목적함수를 Cholesky 분해를 이용하여 제곱 항들의 합 형태로 나타내고, 목적함수 계산 도중 일부의 합이 이미 기존의 최소값 보다 크면 계산을 중단함으로써 검색속도를 향상시키는 새로운 알고리즘을 제안하였다. 제안한 알고리즘의 동작은 소프트웨어 기반의 모의실험을 통하여 검증하였으며 기존 MUSIC 알고리즘과 비교하여 도래각 추정 성능은 같으나 검색속도가 최대 1.15배 향상됨을 확인하였다. The jamming countermeasures in GNSS includes anti-jamming technique and jammer localization technique. In both techniques, direction of jamming signal is important and generally the MUSIC algorithm is used to find the direction of jamming signal. The MUSIC is super-resolution algorithm for detecting incident direction of signal. But, the search time of MUSIC algorithm is too long because all candidates of incidence angle are searched. This paper proposes the new method that has less computational burdens and therefore faster than the conventional MUSIC algorithm. The proposed method improves performance speed by reducing unnecessary calculations. In the proposed method, the cost function of conventional MUSIC algorithm is decomposed into the sum of squares and if the partial sum of cost function is larger than the minimum cost function so far, then the candidate is rejected and next candidates are searched. If the computed cost function is less than the minimum cost function so far, the minimum cost function so far is replaced with newly computed value. The performance of the proposed method was compared with the conventional MUSIC algorithm using the simulation. The accuracy of the estimaed direction of jamming signal was same as the conventional MUSIC while the search speed of the proposed method was 1.15 times faster than the conventional MUSIC.
거리에 비례하는 오차를 고려한 eLoran 항법 알고리즘
송세필(Se Phil Song),최헌호(Heon Ho Choi),김영백(Young-Baek Kim),이상정(Sang Jeong Lee),박찬식(Chansik Park) 대한전기학회 2011 전기학회논문지 Vol.60 No.12
eLoran is enhanced Loran-C and eLoran is researched for as GPS backup system because this system is resistant to signal interference and has high accuracy. TOA measurements of eLoran include errors proportional to the range such as PF, SF, ASF and EF. Therefore these error factors must be compensated for improved accuracy of position. Generally, error models or GPS aided compensation methods are used, but these methods are limited by lack of infrastructure or system performance. Therefore, this paper proposes new model of error factors included in eLoran TOA measurements and navigation algorithm using this model. Error factors in this model are sum of a certain size of error and error proportional to the range. And feasibility and performance of proposed navigation algorithm are verified by using raw measurements.
실제 eLoran TOA 측정치를 이용한 GPS Aided 오차 보상 기법과 항법 알고리즘의 검증
송세필(Se Phil Song),최헌호(Heon Ho Choi),김영백(Young-Baek Kim),이상정(Sang Jeong Lee),박찬식(Chansik Park) 제어로봇시스템학회 2011 제어·로봇·시스템학회 논문지 Vol.17 No.9
The Loran-C, a radio navigation system based on TDOA measurements is enhanced to eLoran using TOA measurements instead of TDOA measurements. Many error factors such as PF, SF, ASF, clock errors and unknown biases are included in eLoran TOA measurements. Because these error factors can cause failure in eLoran navigation algorithm, these errors must be compensated for high accuracy eLoran navigation results. Compensation of ASF and unknown biases are difficult to calculate, while the others such as PF and SF are relatively easy to eliminate. In order to compensate all errors in eLoran TOA measurements, a simple GPS aided bias compensation method is suggested in this paper. This method calculates the bias as the difference of TOA measurement and the range between eLoran transmitters and the receiver whose position is determined using GPS. The real data measured in Europe are used for verification of suggested method and navigation algorithm.