• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.15 no.3
• /
• pp.311-318
• /
• 2004

It is required to design the RF link with sufficiently stable signal margin to minimize bit errors and improve the quality of received data in the telemetry system modulated digitally like PCM/FM. In case of the vehicle flying at a high speed, the variation of the gain pattern between transmitting and receiving antenna and the fee space loss due to flight distance cause the fluctuation of link. In this paper, KSR(Korea Sounding Rocket)- III, the first domestic liquid rocket which was successfully launched in Nov. 2002 is introduced. The SNR(signal-to-noise ratio) variation of the telemetry signal which was measured at S-band ground station, the one which was simulated considering the flight trajectory, and the attitude variation such as roll, pitch and yaw are compared, analyzed, and agree very well. In addition, two virtual flying situations are simulated and evaluated-only one antenna is equipped in one case, and rocket is roll-free in the other.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.48 no.11
• /
• pp.927-933
• /
• 2020

This paper presents a fuel quantity measurement system (FQMS) for an aircraft supplementary fuel tank considering the change of aircraft attitude. The developed FQMS consists of fuel sensors, a signal process unit, an indicator and a software to estimate the fuel quantity from the sensor data. To replicate the change of the roll and pitch attitude on the ground, the test simulator is developed in this work. Using the test simulator, the sensor data at various fuel quantities, roll and pitch angles are automatically measured to build a training data set. The data-driven software to estimate the fuel quantity is then developed using a trilinear interpolation method with the training data set. The developed FQMS is verified by investigating the fuel estimation error of the test data set that we know the true values. Through the test, it is confirmed that the error of the developed FQMS system satisfies the criteria of TSO-C55 document.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.10
• /
• pp.79-88
• /
• 2003

The paper presented here covers the work associated with the flight control law design, ground based and in flight simulation and handling qualities assessment of the Fly-by-Wire type Aircraft (FBWA). The FBWA configurations are of the same generic form of the Korean advanced trainer. The normal acceleration (Nz) and pitch rate (q) feedback control system is employed for longitudinal axis and roll rate (p) and lateral acceleration (Ny) feedback flight control law is developed in lateral/ directional axis. The flight tests for the FBW A dynamics evaluation were executed for the target aircraft (FBWA) on the IFS (In-Flight-Simulator) aircraft . The test results showed that Level 1 handling qualities for the most unstable flight regime and Level 1/2 for the landing approach flight regime were achieved. And the designed FBWA flight control law has revealed acceptable CHR (Cooper-Harper handling qualities Ratings).

• Journal of Advanced Navigation Technology
• /
• v.22 no.2
• /
• pp.111-122
• /
• 2018

At present, the ground transportation system is saturated in many countries including Korea. To overcome this problem, many researches of developing a roadable personal air vehicle (PAV) are being carried out to alleviate traffic congestion and to accomplish door-to-door mobility through three-dimensional traffic system. In this study, the thrust-to-weight ratio, the wing loading, and the power-to-weight ratio that are major design parameters for the sizing of roadable PAVs were calculated under the constraints of ground roll, climb rate, maximum cruise speed, service ceiling, stall speed. Also, in the sizing process, the study was conducted to determine the design point using the graphs of thrust-to-weight ratio, wing loading, power-to-weight ratio, and brake horse power for the mission profiles considering domestic environments and the FAR PART 23 which is the GA class aircraft certification standard.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2004.04a
• /
• pp.15-26
• /
• 2004

The calibration for systematic error in LiDAR is crucial for the accuracy of airborne laser scanning. The main error is the misalignment of platforms between INS(Inertial Navigation System) and Laser scanner For planimetrical calibration of LiDAR, the building is good feature which has great changes in height and continuous flat area in the top. The planimetry error(pitch, roll) is corrected by adjustment of height which is calculated from comparing ground control points(GCP) of building to laser scanning data. We can know scale correction of laser range by the comparison of LiDAR data and GCP is arranged at the end of scan angle where maximize the height error. The area for scale calibration have to be large flat and have almost same elevation. At 1000m for average flying height, The Accuracy of laser scanning data using LiDAR is within 110cm in height and ${\pm}$50cm in planmetry so we can use laser scanning data for generating 3D terrain surface, expecically digital surface model(DSM) which is difficult to measure by aerial photogrammetry in forest, coast, urban area of high buildings

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.4
• /
• pp.169-176
• /
• 2000

Longitudinal and lateral forces acting on tires are known to be closely related to the tract-ability braking characteristics handling stability and maneuverability of ground vehicles. In thie paper in order to develop tire force monitoring systems a monitoring model is proposed utilizing not only the vehicle dynamics but also the roll motion. Based on the monitoring model three monitoring systems are developed to estimate the tire force acting on each tire. Two monitoring systems are designed utilizing the conventional estimation techniques such as SMO(Sliding Mode Observer) and EKF(Extended Kalman Filter). An additional monitoring system is designed based on a new SKFMEC(Scaled Kalman Filter with Model Error Compensator) technique which is developed to improve the performance of EKF method. Tire force estimation performance of the three monitoring systems is compared in the Matlab simulations where true tire force data is generated from a 14 DOF vehicle model with the combined-slip Magic Formula tire model. The built in our Lab. simulation results show that the SKFMEC method gives the best performance when the driving and road conditions are perturbed.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.13 no.1
• /
• pp.50-58
• /
• 2013

Estimating a driver's head pose is an important task in driver-assistance systems because it can provide information about where a driver is looking, thereby giving useful cues about the status of the driver (i.e., paying proper attention, fatigued, etc.). This study proposes a system for estimating the head pose using monocular images, which includes a novel use of backprojection. The system can use a single image to estimate a driver's head pose at a particular time stamp, or an image sequence to support the analysis of a driver's status. Using our proposed system, we compared two previous pose estimation approaches. We introduced an approach for providing ground-truth reference data using a mannequin model. Our experimental results demonstrate that the proposed system provides relatively accurate estimations of the yaw, tilt, and roll angle. The results also show that one of the pose estimation approaches (perspective-n-point, PnP) provided a consistently better estimate compared to the other (pose from orthography and scaling with iterations, POSIT) using our proposed system.

• Aerospace Engineering and Technology
• /
• v.6 no.1
• /
• pp.35-44
• /
• 2007

In this study was made the flutter analysis for the export model of Firefly(Bandi-ho), the small canard aircraft. Stiffness model based on internal load generation finite element model was generated. Mass model based on the weight DB for weight control was generated. Aerodynamic model based on Doublet Lattice Method was generated. Preliminary flutter analysis was made. Based on it, major vibration modes are identified and experimentally obtained via the ground vibration test. The obtained normal mode frequencies were used to correlate the finite element model. Flutter analysis was made again and major flutter mechanisms were summarized. The most important flutter root was identified as a coupled root between rigid body roll mode and anti-symmetric wing pitching mode.

• Journal of electromagnetic engineering and science
• /
• v.10 no.3
• /
• pp.92-98
• /
• 2010

A new wideband bandstop filter(BSF) with a sharp roll-off characteristic is introduced in a stripline structure in this paper. The BSF consists of two sections: the first is two capacitively coupled $\lambda/4$ short-circuited lines with opposite ground positions, while the second is a capacitively coupled $\lambda/4$ short-circuited line. The BSF provides three transmission zeros within the stopband and better than 22 dB rejection over the whole wireless local area network (WLAN) band from 5.15 to 5.825 GHz. The BSF, cascaded to an U.S. ultra-wideband(UWB: 3.1~10.6 GHz) band-pass filter(BPF), is simulated with HFSS and realized with low-temperature co-fired ceramic(LTCC) green tape with a dielectric constant of 7.8. The measurement results agree well with the HFSS simulation results. The size of the UWB BPF including the BSF is $3{\times}6.3\times0.45\;mm^3$.

• Journal of the Korean Society for Precision Engineering
• /
• v.31 no.10
• /
• pp.913-922
• /
• 2014

This paper describes design of a robotic above-knee prosthetic leg which is powered by electrical motors. As a special feature, the robotic prosthetic leg has enough D.O.F.s. For mimicking the human leg, the robotic prosthetic leg is composed of five joints. Three of them are called 'active joint' which is driven by electrical motors. They are placed at the knee-pitch-axis, the ankle-pitch-axis, and the an! kle-roll-axis. Every 'active joint' has enough torque capacity to overcome ground reaction forces for walking and is backlashless for accurate motion generation and high-performance balance control. Other two joints are called 'passive joint' which is activating by torsion spring. They are placed at the toe part and designed by Crank-rocker mechanism using kinematic design approach. In order to verify working performance of the robotic prosthetic leg, we designed a gait trajectory through motion capture technique and experimentally applied it to the robot.