• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.6
• /
• pp.229-235
• /
• 2018

Research on indoor location tracking technology using smart phone is actively being carried out. Especially, in order to display the movement path of the smartphone on the map, the azimuth angle should be estimated by using the geomagnetic sensor built in most smart phones. Due to the distortion of the magnetic field due to the surrounding steel structure and the inclination of the smartphone, the estimation error of azimuthal angle may be occurred. In this paper, we propose a correction method of the geomagnetic sensor at the stationary state and a correction method for the inclination of the smartphone. We also propose a method to correct the azimuth error due to the difference between the magnetic north and the grid north.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2014.06a
• /
• pp.20-22
• /
• 2014

교차방위법은 해군 함정이 연안항해에서 주로 사용하는 함위 산출법이다. 항해 보조장비가 많이 개발되었음에도 불구하고 실물표를 대상으로 측정하는 실측위치이기 때문에 해군함정에서 현재까지 가장 폭넓게 활용되고 있다. 교차방위법의 정확도에 미치는 영향요소는 여러가지가 있지만, 본 논문에서는 함정의 기본속력이 미치는 영향을 연구하였다. 긴급한 작전상황의 경우 함정은 안전속력보다 빠른 속력으로 협수로를 통과해야 한다. 이러한 작전환경에서 속력의 증가가 얼마나 위치 정확도의 오차를 가져오는지 확인하여 함정을 운용하는 지휘관에게 참고자료를 제공하고자 한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.8
• /
• pp.1-7
• /
• 2005

We introduced the method to obtain four speckle patterns with relative phase shift of ${\pi}/2$ by the polarizing elements, and calculate the phase at each point of the speckle pattern in shearography using Wollaston prism and polarizing elements. Ant we analyzed the phase error caused by the azimuth angles of wave plates used in the proposed method by Jones matrix.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 1996.04a
• /
• pp.31-40
• /
• 1996

• Journal of Digital Convergence
• /
• v.12 no.11
• /
• pp.373-378
• /
• 2014

The technology of direction finding is very important to make high position fixing accuracy. TDOA(time difference of arrival) direction finding technology is a high accuracy technology and is used in RF system from 1990. The principle of TDOA is to receive an emitter signal with two antennas, measure the time difference of received signal and then convert the time differences to azimuth angle. For high DF(direction finding) accuracy long basis line and high SNR at receiving system are needed. The DF accuracy and position fixing accuracy are simulated with different SNRs and antenna base lines. We obtain the DF accuracy of $0.51^{\circ}$ at $0^{\circ}$ incident azimuth angle in case of 50m base line and 40dB SNR.

• Journal of the Institute of Electronics Engineers of Korea TE
• /
• v.42 no.2
• /
• pp.1-6
• /
• 2005

Ryu et al. proposed a multiple target DOA tracking algorithm using a linear sensor array. In Ryu's algorithm first, the signal subspace is estimated using sensor output and the angular innovations of targets are extracted from the estimated signal subspace. Next, the DOA's of targets are tracked using the angular innovations as the inputs of Kalman filters. Ryu's algorithm has good features that it has no data association problem and is efficient. However, Ryu's algorithm can't be a lied to an arbitrarily shaped array because it was proposed using linear sensor array. Actually, when the sensor array is used in the various application fields, sensors have a position error. Therefore, the sensor array can be an arbitrarily shaped array. In this paper, we propose a multiple target DOA tracking algorithm applicable to an arbitrarily shaped array, and it sustains the good features of Ryu's algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38A no.9
• /
• pp.782-791
• /
• 2013

This paper proposes the location estimation techniques of distributed targets with the multi-sensor data perceived through IR sensors of the military robots. In order to match up targets with measured azimuths, we apply the maximum likelihood (ML), depth-first, and breadth-first tree search algorithms, in which we use the measured azimuths and the number of pixels on IR screen for pruning branches and selecting candidates. After matching up targets with azimuths, we estimate the coordinate of each target by obtaining the intersection point of the azimuths with the least square error (LSE) algorithm. The experimental results show the probability of missing target, mean of the number of calculating nodes, and mean error of the estimated coordinates of the proposed algorithms.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.38 no.6
• /
• pp.1-8
• /
• 2001

Recently, Ryu et al. proposed a multiple target angle tracking algorithm using the angular innovation extracted from the estimated signal subspace. This algorithm obtains the angles of targets and associates data simultaneously. Therefore, it has a simple structure without data association problem. However it requires the calculation of the inverse of a real matrix with dimension (2N+1)${\times}$(2N+1) to obtain the angular innovations of N targets. In this paper, a new linear equation for angular innovation is proposed using the fact that the projection error is zero when the target steering vector is projected onto the signal subspace. As a result, the proposed algorithm dose not require the matrix inversion and is computationally efficient.

• Defense and Technology
• /
• no.6 s.136
• /
• pp.28-35
• /
• 1990

재래식 총은 발사체의 속도가 너무 낮기 때문에 이동하는 목표물에 대한 명중률이 낮으므로, 현대전은 발사체 속도를 높이기를 요구한다. 이 문제는 대공화기에서 특히 절실하며, 그것은 공격하는 비행체의 속도와 고도 증가에 보조를 맞추지 못해 왔기 때문이다. 또한 실제적인 표적거동에 대하여 조준점과 탄착점과의 오차 거리는 비행시간의 제곱에 좌우되므로, 전자기 총은 사격제어 오차의 영향을 80-90%까지 감소시킬수 있다. 종말탄도 조건은 장갑두께가 변할 때 변하므로 대장갑 교전에서는 균일장갑에만 해당되나, 그럼에도 불구하고 대장갑 교전에서 장점이 기대된다

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.6
• /
• pp.87-92
• /
• 2001

An error analysis is very important for a precision machine to estimate its performances. This study proposes a new parallel device, cubic parallel manipulator. Errors of the proposed cubic parallel manipulator include upper and down universal joint errors, due to the directional changes in the forces in the links, and actuation errors. An error analysis is presented based on an error model formed through the relation between the universal joint errors of the cubic parallel manipulator and the end effector accuracy. The analysis shows that the method can be used in predicting the accuracy of other cubic parallel devices.