• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.2
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• pp.108-117
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• 2012

This paper focuses on a performance analysis of TRN among various nonlinear filtering methods. In a TRN research, extended Kalman filter(EKF) is a basic estimation algorithm. In this paper, iterated EKF(IEKF), EKF with stochastic linearization(SL), and unscented Kalman filter(UKF) algorithms are introduced to compare navigation performance with original EKF. In addition to introduced sequential filters, bank of Kalman filters method, which is one of the batch method, is also presented. Finally, by simulating an artificial aircraft mission, EKF with SL was chosen as the most consistent filter in the introduced sequential filters. Also, results suggested that the bank of Kalman filters can be alternative for TRN, when a fast convergence of navigation solution is needed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.11
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• pp.1069-1076
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• 2011

All of the satellite components must be operated within the permissible temperature range during the mission in orbit. Therefore, thermal design is performed to develop verified thermal model and to secure thermal stability on the ground. In this study, thermal model correlation was performed to satisfy the criteria of correlation using ground thermal vacuum/thermal balance test results of LEO satellite optical payload. We also secured verified thermal model by controlling operating cycle of flight heaters. In addition, it was confirmed that all components are within the permissible temperature range through conducting orbit environment thermal analysis. We also secured thermal stability of the satellite.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.10
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• pp.910-919
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• 2015

A weapon control algorithm equipped on a fighter is closely related to the mission accomplishment and fighter survivability during the engagement. In the case of a air-to-surface missile, the weapon control algorithm typically provides a pilot the target shoot-down possible region known as launch acceptability region(LAR) in the multi function display(MFD). LAR is produced by the range table(RT) through computation of an engagement range. In this paper, the operation system of AGM-84 and AGM-88 air-to-surface missiles is introduced. And the engagement range computation and LAR algorithm based on the real-time pseudo 6-DOF simulation are proposed. In order to verify the performance of the algorithm, numerical engagement simulations of air-to-surface missiles to produce LAR have been done.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.6
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• pp.530-536
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• 2016

The handling quality simulator including high fidelity flight mechanics model is indispensable component to design and verify the flight control system. Korea Aerospace Industries, LTD. (KAI) has been performing LCH (Light Civil Helicopter) core technology development program regarding automatic flight control system (AFCS) software development. And KAI has been developing flight mechanics model using FLIGHTLAB to design and evaluate the AFCS flight control law. This paper presents the handling quality assessment environment development results through the combining FLIGHTLAB with a legacy simulator. And this paper details the FLIGHTLAB model, application development process and FLIGHTLAB interface design. The developed handling quality assessment environment has been demonstrated with the ADS-33E hover and pirouette MTE (Mission Task Element) maneuver simulation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.9
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• pp.779-788
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• 2014

The satellite should generate electric power efficiently to perform the mission successfully within limited power. For this reason, the electrical power system of LEO satellites usually regulates the power which is generated from the solar cells using MPPT (Maximum Power Point Tracking) method. This paper proposes advanced MPPT algorithm based on the fuzzy logic applied to small CubeSat satellite. The simulation has been performed to confirm the validity of the proposed method by interlocking between MATLAB/Simulink and STK (Systems Tool Kit). The EBA(Energy Balance Analysis) has also been performed at two different pointing modes of KAUSAT-5 for solar irradiation according to the satellite orbit and attitude, and load capacity varied with operation modes by Simulink and STK. The performance of fuzzy logic-based MPPT algorithm was verified through the EBA. The validity of the proposed MPPT algorithm based on the fuzzy logic was also confirmed by comparing with P&O (Perturbation & Observation) algorithm that is general in the MPPT.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.9
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• pp.762-772
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• 2014

A weapon control algorithm equipped on a fighter is closely related to the mission accomplishment and fighter survivability during engagement. The weapon control algorithm typically provides a pilot the dynamic launch zone(DLZ), the target shoot-down range of air-to-air missiles, in the head-up display(HUD). DLZ is produced by an engagement range computation algorithm. In this paper, the components of DLZ for AIM-9 and AIM-120 air-to-air missiles are introduced. The real-time computation algorithm for DLZ based on the pseudo 6-DOF program is then addressed The operational aspects of DLZ algorithm for the air-to-air missiles to various engagement scenarios is investigated vis simulations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.1
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• pp.124-131
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• 2002

In this study, a preliminary design code was developed for the initiation of HTPB/LOX hybrid rocket system. HTPB was assumed to have a constant regression rate. And initial input parameters; number of port, initial O/F ratio F/W ratio, and chamber pressure, were varied to analyze the effects on the performance and geometry of rocket system. The results showed a qualitatively good agreement with previous data. And it was revealed that there exists a number of design results that meet the mission requirements and that we could find an optimal design case if a proper constraint would be imposed. Thus, it is natural to account for the optimal algorithm during the design procedure and to consider more realistic and reliable formulations used for weight estimation of structural supports and accessories.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.7
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• pp.105-116
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• 2004

The design of pico-/nano-satellites is particularly challenging due to constraints in mass, volume, power, and surface area. An efficient low-cost picosatellite HAUSAT-1 Electrical Power Subsystem (EPS) is developed to supply the power for various loads during the full mission life. This paper addresses design and analysis results of solar arrays, batteries, power conditioning and distribution units. The component selection, manufacturing and test results are presented by considering appropriate development cost and performance. The simulation results of power system are also illustrated, according to operational modes, through energy balance analysis. Finally, the EFS design feasibility is verified by comparing analysis results with functional and environmental test results at the system and component levels, respectively.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.7
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• pp.92-97
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• 2005

In this paper, the performance of the KOMPSAT-1 GPS receiver on orbit was analyzed. OD (Orbit Determination) accuracy using GPS navigation solutions and GPS visibility were investigated with respect to the configuration of the GPS receiver. Indeed, the problem such as ‘3D Fix Loss’ observed during the mission was presented. As a result, the OD accuracy of ‘Best-of-4’ Position Fix Algorithm with 0 degree of mask angle was slightly better than that of ‘N-in-View’ Position Fix Algorithm. On the other hand, the GPS visibility under ‘N-in-View’ Algorithm is better than that of ‘Best-of-4’ Algorithm. The occurrence of temporal 3D Fix Loss is reduced when the ‘N-in-View’ Position Fix Algorithm was selected.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.4
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• pp.281-289
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• 2016

Accurate prediction of the trajectory and time of a time-varying mass parachute system remains essential in the mission requiring a precision airdrop to the ground. In this study, we investigate the altitude-varying behavior of a cross-type parachute system designed to deliver a time-varying mass object like flare. The dynamics of the descending parachute system was analyzed based on the Runge-Kutta method of the ordinary differential system. The drag coefficients of the cross-type parachute and flare were calculated by a CFD code based on the incompressible Navier-Stokes equation. Finally, by using a simplified gust wind model in troposphere, the combined effects of gust wind and time-varying mass were examined in detail.