• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.51 no.6
• /
• pp.221-227
• /
• 2002

In this paper, the system model for the compensation of the low-cost personal navigation system is derived and the error compensation method using GPS is also proposed. WNS(Walking Navigation System) is a kind of personal navigation system using the number of a walk, stride and azimuth. Because the accuracy of these variables determines the navigation performance, computational methods have been investigated. The step is detected using the walking patterns, stride is determined by neural network and azimuth is calculated with gyro output. The neural network filters off unnecessary motions. However, the error compensation method is needed, because the error of navigation information increases with time. In this paper, the accumulated error due to the step detection error, stride error and gyro bias is compensated by the integrating with GPS. Loosely coupled Kalman filter is used for the integration of WNS and GPS. It is shown by simulation that the error is bounded even though GPS signal is blocked.

• Proceedings of the KIEE Conference
• /
• 2002.07d
• /
• pp.2171-2175
• /
• 2002

Helicopter dynamics are plenty of nonlinearity. A complete mathematical model including propeller dynamics and fortes generated by the propellers is very difficult to obtain. So the method used to design to design a controller is a parameter estimation. Design controller based on variable structure system. This paper deals with LQR control technique to control efficiently, its elevation angle and azimuth one. The purpose of the experiment is to design a controller allows to use a desired elevation angle and azimuth ones. The system model has a helicopter model with 2-degree-of freedom. The simulation results were verified usefulness of controller.

• Journal of electromagnetic engineering and science
• /
• v.13 no.4
• /
• pp.251-258
• /
• 2013

A procedure for antenna parameter selections is proposed that considers the relationships between synthetic aperture radar performance and the antenna parameters of a parabola-type reflector antenna with a central flat dish. The effects of a central dish designed for weight reduction on the antenna beam pattern are also quantitatively analyzed using commercially available software based on the physical optics algorithm. The results of the theoretical analysis and simulation predict that a larger size of the central dish results in an increase in the sidelobe level, which is the reason for the increase in two important ambiguities, such as range ambiguity ratio (RAR) and azimuth ambiguity ratio (AAR). The dependence of RAR and AAR on Pulse repetition frequency is also analyzed and discussed.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.14 no.3
• /
• pp.474-481
• /
• 2011

The Electronic Warfare Computer for the Aircraft Survivability Equipment will improve the ability for countermeasures by analysis about threat information. This paper suggests method that threat data integration of multiple sensors(Radar Warning Receiver, Laser Warning Receiver, Missile Warning Receiver). The algorithm of threat data integration is based on detected threat sequence and azimuth information. The threat sequence information is analyzed in advance and the azimuth data is received from sensors. The suggested method is evaluated through simulation under the environment like real helicopter.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.18 no.1
• /
• pp.84-92
• /
• 2015

This paper proposes a new approach to reduce the target estimation error of the measurement angle, especially applied to the medium and long range surveillance radar. If the target has no maneuver and no change in heading direction for a certain time interval, the predicted angle of interacting multiple model(IMM) from the previous track information can be used to reduce the angle estimation error. The proposed method is simulated in 2 scenarios, a scenario with a non-maneuvering target and a scenario with a maneuvering target. The result shows that the new fusion solution(weighted IMM) with the predicted azimuth and the measured azimuth is worked properly in the two scenarios.

• Journal of Institute of Control, Robotics and Systems
• /
• v.3 no.3
• /
• pp.238-243
• /
• 1997

A new transfer alignment algorithm using the velocity and the quaternion partial matching methods is proposed to reduce the effect of a ship's Y-axis flexure on the performance of azimuth error estimation of Kalman filter. The simulation results show that it can significantly reduce the effect of Y-axis flexure on error estimation by the transfer alignment algorithm. As its results, azimuth transfer alignment error is reached up to 3 mrad under proper roll and pitch attitude motion of the ship.

• Solar Energy
• /
• v.18 no.4
• /
• pp.87-94
• /
• 1998

This work presents a method to compute the sun position(azimuth and elevation), sunrise and sunset times. Accurate computation of sun position is very important to the precise tracking of the sun for the solar concentrator, which enables the maximum collection of solar energy. Methods to compute the sun position are available in the literature already. However most of them do not have accuracy verification, thus makes hard in selecting the most accurate sun position computation method. We first select the most accurate sun position computation method among the methods presented in the literature by comparing the computed sun position with Korean Almanac of Korea Astronomy Observatory. Then a procedure to compute the sunrise and sunset times is presented. Computed sun position shows $0.02^{\circ},\;0.6^{\circ}$ and one minute differences in azimuth, elevation and sunrise/sunset times respectively compared with Korean Almanac.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.3
• /
• pp.606-611
• /
• 2011

This paper proposes a correction method concerning the inclination error and non-horizontal error of magnetic compass when magnetic compass is vibrated. This system used the 2-axis variable resistance and pendulum. A pendulum hanging from the 2-axis variable resistance of this system is always maintain the horizontal because of gravity. but these data had some intrinsic error. So we used the low pass filter to solve this problem. So this system can get the accurate azimuth of magnetic compass. In conclusion, These results demonstrate convincingly by applied algorithm of experiment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.1
• /
• pp.245-251
• /
• 2005

Ship's auto pilot is must necessary the azimuth data, which is supported by a gyro, geomagnetism and GPS compass. The gyro compass is operation of stability & correct , therefore it is used by big size shipping because of high cost. The other side, medium and small size shipping are used the geomagnetism and GPS compass of low cost. This paper have studied that the two jobs are going on at the same time both of there's advantage. Which is asked the algorithm for stability azimuth data on reject methode the defect of respect with geomagnetism & GPS compass.

• Journal of Navigation and Port Research
• /
• v.31 no.9
• /
• pp.751-757
• /
• 2007

The authors aim to establish the theory necessary for developing free gyro positioning system and focus on measuring the nadir angle by using the motion rate of a free gyro. The azimuth of a gyro vector from the North can be given by using the property of the free gyro. The motion rate of the spin axis in the gyro frame is transformed into the platform frame and again into the NED (north-east-down) navigation frame. The nadir angle of a gyro vector is obtained by using the North components of the motion rate of the spin axis in the NED frame. The component has to be transformed into the horizontal component of the gyro by using the azimuth of the gyro vector and then has to be integrated over the sampling interval.