Korea Aerospace Research Institute | Date: 2015-12-01
Provided is an apparatus for controlling an orbiting satellite by sensing a change in a yaw angle of the orbiting satellite and calculating a ground sample distance (GSD) based on the yaw angle. The apparatus may include a sensor configured to sense a yaw angle corresponding to yaw steering of the orbiting satellite, and a processor configured to calculate, based on the yaw angle, a GSD corresponding to a length of a pixel projected onto a planetary surface scanned by the orbiting satellite.
Korea Aerospace Research Institute | Date: 2016-10-13
A solar propelled aircraft which has a wing having solar cell modules mounted therein includes: first solar cell modules which are positioned in a wing or a tail wing of the aircraft and receive solar energy directly from the sun; second solar cell modules which are positioned in a main wing or a tail wing of the aircraft and supplied with directed energy from the earth; and rotating shafts which rotate the first solar cell modules and the second solar cell modules so that the first solar cell modules and the second solar cell modules correspond to each other in both directions. The first solar cell module at the upper surface obtains solar energy from the sun, and the second solar cell module at the lower surface obtains directed energy transferred from the earth.
Korea Aerospace Research Institute | Date: 2015-10-26
A synchronization method between satellite time and ground time, and a satellite system using the same are provided, in which the satellite system includes a satellite and a ground equipment, in which the ground equipment generates a satellite command including information about time difference between the ground time and the satellite time included in a telemetry data frame transmitted from the satellite and transmits the satellite command to the satellite, and the satellite can synchronize the satellite time with the ground time, using the information about the time difference included in the satellite command.
Korea Aerospace Research Institute | Date: 2014-08-19
Provided is a sphere magnetic levitation system having magnetic-aligning devices that magnetically align the position of a sphere levitated by electromagnets according to whether the sphere is levitated, and a method of operating the sphere magnetic levitation system. The sphere magnetic levitation system includes: a sphere; a plurality of electromagnets symmetrically positioned about the sphere and spaced apart from the sphere at equal distances; and a plurality of magnetic-aligning devices provided around the sphere, and coming into contact with the sphere or separated from the sphere by a predetermined distance according to the modes of the system. The system is operated in one mode from among: an idle mode, in which the magnetic-aligning devices are in direct contact with and support the sphere; and an operation mode, in which the magnetic-aligning devices are separated from the sphere and the sphere is levitated and rotated.
Korea Aerospace Research Institute | Date: 2016-08-07
Disclosed is an automatic climbing and gliding method of a high altitude unmanned aerial vehicle (UAV). The disclosed method includes setting a cylindrical virtual flight region so that the high altitude UAV climbs and glides, setting a first target point on an end of a first flight radius which is vertically arranged to form the virtual flight region, setting second to Nth target points at arbitrary second to Nth flight radii sequentially arranged above or below the first flight radius, having the target points have a predetermined plane slope angle, and allowing the UAV to climb along a straight path line sequentially connecting each of the target points.
Lee S.-S.,Korea Aerospace Research Institute
IEEE Transactions on Industrial Electronics | Year: 2014
A new step-down converter is presented. It is composed of an auxiliary switch, a diode, and a coupled winding to the buck inductor in the conventional buck converter. By transferring the buck-inductor current to the coupled winding in a very short period, the negatively built-up leakage inductor current of the buck winding guarantees the zero-voltage switching (ZVS) operation of the buck switch in all load conditions. Furthermore, since the negatively built-up leakage inductor current is minimized after the zero voltage of the buck switch is achieved, the unnecessary current build-up and the conduction loss are minimized. Therefore, efficient ZVS operation with load variation is achieved. The operation principle, ZVS analysis, design, and experimental results of the proposed converter are presented. © 1982-2012 IEEE.
Korea Aerospace Research Institute | Date: 2016-01-29
The present invention relates to a method for controlling land surface temperature using stratospheric airships and a reflector. In the method for controlling land surface temperature using stratospheric airships and a reflector, four corners are connected to a lower end of support lines coupled to be disposed vertically downward from a plurality of airships, and sunlight is reflected by a reflector unfolded into a tetragonal shape in the air, wherein the reflecting surface of the reflector plate is maintained at an angle to remain perpendicular to an incident angle of sunlight to shield, or redirect, the land surface from incident sunlight.
Korea Aerospace Research Institute | Date: 2016-01-20
An apparatus and method for containing and charging an unmanned VTOL aircraft are disclosed. The apparatus for containing and charging an unmanned VTOL aircraft includes a post 110, an extended member 120, a cover 130, a fastening unit 140, and a charging unit 150. The post is placed on a ground. The extended member is connected to the post. The cover is provided on the extended member, and is configured to be opened or closed in order to contain and protect the unmanned VTOL aircraft. The fastening unit is provided in the cover, and is configured to fasten the unmanned VTOL aircraft. The charging unit is provided in the fastening unit, and is configured to charge the unmanned VTOL aircraft.
Korea Aerospace Research Institute | Date: 2016-07-20
An apparatus and method of charging and housing of an unmanned vertical take-off and landing (VTOL) aircraft is disclosed. The apparatus includes an accommodator to accommodate an aircraft, a landing platform on which the aircraft lands, a housing portion to monitor state data by housing or charging the aircraft, and a sensor to assist in landing of the aircraft by allowing the aircraft to communicate with the apparatus. The apparatus enhances operational efficiency by reducing a travel time of the aircraft.
Manufacture Of Metal Core By Using Rapid Prototyping Method And Method For Manufacturing Precision Parts Through Hot Isostatic Pressing Using Same, And Turbine Blisk For Driving Liquid Rocket Turbo Pump Using Same
Korea Aerospace Research Institute | Date: 2016-10-26
Disclosed is a method for manufacturing precision parts through hot isostatic pressing using a metal core manufactured through metal rapid prototyping to manufacture a turbine blisk for driving a turbo pump of a liquid rocket. The method includes: manufacturing a metal core that has an internal vacant space having the same shape as the precision parts, using rapid prototyping; putting the metal core in a housing; filling an inside of the housing with heat resistant steel powder and creating a vacuum state in the housing; treating the housing under high temperature and pressure to produce heat resistant steel; removing the housing and a portion of the heat resistant steel to expose a portion of the metal core; performing etching to remove the exposed metal core; and removing only a portion of the heat resistant steel through mechanical machining, wherein the remaining portion corresponds to the shape of the precision part.