Analysis of Scaling Parameters of the Batch Unscented Transformation for Precision Orbit Determination using Satellite Laser Ranging Data

김재혁,박상영,김영록,박은서,조중현,임형철,박장현,박종욱 한국우주과학회 2011 Journal of Astronomy and Space Sciences Vol.28 No.3

The current study analyzes the effects of the scaling parameters of the batch unscented transformation on precision satellite orbit determination. Satellite laser ranging (SLR) data are used in the orbit determination algorithm, which consists of dynamics model, observation model and filtering algorithm mposed of the batch unscented transformation. TOPEX/Poseidon SLR data are used by utilizing the normal point (NP) data observed from ground station. The filtering algorithm includes a repeated series of processes to determine the appropriate scaling parameters for the batch unscented transformation. To determine appropriate scaling parameters, general ranges of the scaling parameters of α, β, κ, λ are established. Depending on the range settings, each parameter was assigned to the filtering algorithm at regular intervals. Appropriate scaling parameters are determined for observation data obtained from several observatories, by analyzing the relationship between tuning properties of the scaling parameters and estimated orbit precision. The orbit determination of satellite using the batch unscented transformation can achieve levels of accuracy within several tens of cm with the appropriate scaling parameters. The analyses in the present study give insights into the roles of scaling parameters in the batch unscented transformation method.

Unscented Transform을 이용한 단어 신뢰도 추정

김병돈 ( Byoung Don Kim ),김진영 ( Jin Young Kim ),나승유 ( Seung You Na ) 전남대학교 전자통신기술연구소 2008 전자통신기술논문지 Vol.11 No.1

자동 음성 인식에서 일반적으로 신뢰도는 오인식 단어에 대한 거절을 평가하는데 사용된다. 음성 인식 시스템은 인식 단어에 대한 평가를 위하여 반 모델, 특히 반음소 모델을 사용한다. 즉, 최종 평가에 사용되는 단어 신뢰도는 음소 단위 신뢰도의 비선형 결합을 통하여 계산되어진다. 따라서 단어 인식에서 단어 신뢰도 추정이 가능하다면 단어 독립 고립단어 인식에서 고정된 임계값을 통하여 특정 단어를 효과적으로 제거할 수 있을 것이다. 그러나 단어 단위 신뢰도의 통계 값은 일반적으로 일정하지 못하다. 따라서 본 논문에서는 음소 단위 신뢰도 값을 unscented transform을 통하여 단어 신뢰도를 추정하는 간단하고 효율적인 방안에 대하여 제안한다. 실험 결과, 트리이폰 신뢰도를 unscented transform 하였을 때의 단어 신뢰도 추정 성능이 우수함을 알 수 있다. Confidence measure(CM) is generally used for the rejection of mis-recognized words in automatic speech recognition(ASR). Common ASR systems test recognized words with anti-models, especially anti-phone models. That is, they calculate a word confidence with a nonlinear function, which weight nonlinearly phone-level CMs. Word confidence estimation is important in word-independent isolated word recognition, for the fixed threshold can cut out some words excessively. The statistics of word-level confidences are not consistent. In this paper we present a simple and efficient method for estimating word confidence using the unscented transform with the statistics of phone-level confidence values. Our experimental results show that the unscented transform with tri-phone-based CM statistics can estimate word confidence reasonably.

Heterogeneous Sensor-Based Target Tracking With Constant Time Delay

Qilong Wang,Yu Zhang 한국항공우주학회 2021 International Journal of Aeronautical and Space Sc Vol.22 No.1

Aiming to address the problem of constant-step-lag in-sequence measurements (CISM) in the process of heterogeneous sensor tracking, an Unscented Transformation-based CISM indirect update algorithm is proposed in this paper. First, based on the classical A1 algorithm, Unscented Transformation is applied to the nonlinear measurement equation to solve the computation of nonlinear systems. This method does not need to solve the Jacobian matrix or Hessian matrix of nonlinear equations. Second, combined with the complementarity of information from heterogeneous sensor systems, CISM is further analyzed, and an indirect update algorithm is proposed to obtain the approximate estimate of the current time of the delay information, which is substituted into UT-A1 to complete a delay information update algorithm that is suitable for the heterogeneous sensor system in this paper. Finally, the experimental results show that the UT-CISM indirect update algorithm can effectively improve the real-time capability and accuracy of the time-delay sensor system in this paper.

무향 변환 기반 필터링을 이용한 전술표적 추적 성능 연구

변재욱,정효영,이새움,김기성,김기선,Byun, Jaeuk,Jung, Hyoyoung,Lee, Saewoom,Kim, Gi-Sung,Kim, Kiseon 한국군사과학기술학회 2014 한국군사과학기술학회지 Vol.17 No.1

Tracking the tactical object is a fundamental affair in network-equipped modern warfare. Geodetic coordinate system based on longitude, latitude, and height is suitable to represent the location of tactical objects considering multi platform data fusion. The motion of tactical object described as a dynamic model requires an appropriate filtering to overcome the system and measurement noise in acquiring information from multiple sensors. This paper introduces the filter suitable for multi-sensor data fusion and tactical object tracking, particularly the unscented transform(UT) and its detail. The UT in Unscented Kalman Filter(UKF) uses a few samples to estimate nonlinear-propagated statistic parameters, and UT has better performance and complexity than the conventional linearization method. We show the effects of UT-based filtering via simulation considering practical tactical object tracking scenario.

Sensorless Speed Control of Permanent Magnet Synchronous Motor by Unscented Kalman Filter using Various Scaling Parameters

Cheol Moon,Young Ahn Kwon 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.2

This paper investigates the application, design and implementation of unscented Kalman filter observer using the various scaling parameters for the sensorless speed control of a permanent magnet synchronous motor. The principles of unscented transformation and unscented Kalman filter are examined and their applications are explained. Typically the mapping transformation process is divided into two types, namely the basic unscented transformation and the general unscented transformation by virtue of the scaling parameter value. And resultantly, the number of sampling points, weights, code configuration and computation time are different. But there is no little information on the scaling parameter value or how this value influences the system performance. To analyze the unscented transformation with the various scaling parameters in this study, the experimental results under a wide range of operation condition have been demonstrated.

Sensorless Speed Control of Permanent Magnet Synchronous Motor by Unscented Kalman Filter using Various Scaling Parameters

문철,권영안 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.2

This paper investigates the application, design and implementation of unscented Kalman filter observer using the various scaling parameters for the sensorless speed control of a permanent magnet synchronous motor. The principles of unscented transformation and unscented Kalman filter are examined and their applications are explained. Typically the mapping transformation process is divided into two types, namely the basic unscented transformation and the general unscented transformation by virtue of the scaling parameter value. And resultantly, the number of sampling points, weights, code configuration and computation time are different. But there is no little information on the scaling parameter value or how this value influences the system performance. To analyze the unscented transformation with the various scaling parameters in this study, the experimental results under a wide range of operation condition have been demonstrated.

Sensorless Speed Control of Permanent Magnet Synchronous Motor by Unscented Kalman Filter using Various Scaling Parameters

Moon, Cheol,Kwon, Young Ahn The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.2

This paper investigates the application, design and implementation of unscented Kalman filter observer using the various scaling parameters for the sensorless speed control of a permanent magnet synchronous motor. The principles of unscented transformation and unscented Kalman filter are examined and their applications are explained. Typically the mapping transformation process is divided into two types, namely the basic unscented transformation and the general unscented transformation by virtue of the scaling parameter value. And resultantly, the number of sampling points, weights, code configuration and computation time are different. But there is no little information on the scaling parameter value or how this value influences the system performance. To analyze the unscented transformation with the various scaling parameters in this study, the experimental results under a wide range of operation condition have been demonstrated.

무향변환을 이용한 비선형 필터에 대한 연구

윤장호,Yoon, Jangho 항공우주시스템공학회 2016 항공우주시스템공학회지 Vol.10 No.1

The optimal estimation of a general continuous-discrete system can be achieved through the solution of the Fokker-Planck equation and the Bayesian update. Due the high nonlinearity of the equation of motion of the system and the measurement model, it is necessary to linearize the both equation. To avoid linearization, the filter based on Fokker-Planck equation is designed. with the unscented transformation update mechanism, in which the associated Fokker-Planck equation was solved efficiently and accurately via discrete quadrature and the measurement update was done through the unscented transformation update mechanism. This filter based on the Direct Quadrature Moment of Method(DQMOM) and the unscented transformation update is applied to the bearing only target tracking problem. The proposed filter can still provide more accurate estimation of the state than those of the extended Kalman filter especially when measurements are sparse. Simulation results indicate that the advantages of the proposed filter based on the DQMOM and the unscented transformation update make it a promising alternative to the extended Kalman filter.

센서리스 영구자석 동기전동기의 상태 추정을 위한 병렬 축소 차수 제곱근 무향 칼만 필터

문철(Cheol Moon),권영안(Young-Ahn Kwon) 대한전기학회 2016 전기학회논문지 Vol.65 No.6

This paper proposes a parallel reduced-order square-root unscented Kalman filter for state estimation of a sensorless permanent-magnet synchronous motor. The appearance of an unscented Kalman filter is caused by the linearization process error between a real system and classical Kalman model. The unscented transformation can make a more accurate Kalman model. However, the complexity is its main drawback. This paper investigates the design and implementation of the proposed filter with Potter and Carlson square-root form. The proposed parallel reduced-order square-root unscented Kalman filter reduces memory and code size, and improves numerical computation. And the performance is not significantly different from the unscented Kalman filter. The experimentation is performed for the verification of the proposed filter.

위치 센서 없는 전동기 구동장치를 위한 스케일링 파라미터에 따른 무향 변환

문철(Cheol Moon),권영안(Young-Ahn Kwon) 대한전자공학회 2016 전자공학회논문지 Vol.53 No.6