Korea Aerospace Research Institute

Hyeon-Cheol Lee

Seung Hoon Lee

Sungwook Hong

Sang Burm Ryu

Eun Su Kang

Eun-Su Kang

Sang Soon Yong

Sang-soon Yong

Sang Gyu Lee

The present invention relates to a passive microwave sounder for a satellite, having a fixed reflection plate. The passive microwave sounder for a satellite, having a fixed reflection plate includes: a motorincluding a first rotary shaftformed to extend in a progressing direction of a satellite; a first rotating reflection plateforming a predetermined angle with respect to the ground surface of a nadir direction and having a first one-side surfaceand a first other-side surface, the center of the first one-side surfacebeing coupled to and rotating with the first rotary shaft, such that the first one-side surfaceand the first other-side surfacealternately face the ground surface, and the second other-side surfacereflecting incident electromagnetic waves; an auxiliary reflection partreflecting the electromagnetic waves incident from the first other-side surfaceto a predetermined position; a reception partreceiving the electromagnetic waves reflected from the auxiliary reflection part; and a fixed reflection platefixed above the first rotating reflection plateat a predetermined angle with the ground surface and reflecting the electromagnetic waves to the first one-side surfaceor the first other-side surface

Passive microwave sounder for satellite, having fixed reflection plate

Disclosed is a method for four-path tree structured vector quantization, comprising: (a) placing codebook vectors where magnitudes of vectors are arranged in order at lowermost nodes; (b) configuring upper nodes by averaging vector values of the lowermost adjacent four nodes; (c) calculating mean square errors to paths of the upper nodes (A, B, C, and D) corresponding to four paths from an input vector 'X'; (d) presetting a threshold between 0 and 1 after the '(c)'; (e) calculating thresholds between the input vector &#x2018;X&#x2019; and four paths &#x2018;A&#x2019;, &#x2018;B&#x2019;, &#x2018;C&#x2019;, and &#x2018;D&#x2019;, based on the mean square errors; and (f) comparing the thresholds calculated in the &#x2018;(d)&#x2019; with the preset threshold to select a path having a threshold greater than the preset threshold, in which dynamic four-path tree structured vector quantization is used instead of conventional dynamic two-path tree structured vector quantization, thereby more efficiently and quickly searching a codebook.

Method for four-path tree structured vector quantization

Disclosed herein are a system for automatically landing an aircraft using image signals and a method of controlling the system. The system includes an altimeter installed on the aircraft; a landing mark placed at a landing location on a landing runway; a camera installed on the aircraft, oriented toward the front of the aircraft, and configured to detect the shape of the landing mark in image information form; and a FCC configured to calculate the angle between the aircraft and the ground, the ground range and the slant range between the aircraft and the landing location using the altitude information measured by the altimeter, the image information of the landing mark captured by the camera, angle information composed of the pitch, roll and yaw angles of the aircraft, and the angle of entry into the landing runway, and configured to control the automatic landing of the aircraft.

System for automatically landing aircraft using image signals and method of controlling the same

Provided is an altitude measurement apparatus and method that may measure an altitude of an aircraft without using a separate altimeter. The altitude measurement apparatus may include a camera unit being provided to a vertical takeoff and landing (VTOL) aircraft to collect an image of a circular mark formed on the ground, and a calculation unit to calculate an altitude of the VTOL aircraft based on the collected image. Accordingly, the altitude measurement apparatus may measure the altitude using a simple structure such as the circular mark formed on the ground, and be configured at inexpensive costs.

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Daejeon, South Korea

Hyeon-Cheol Lee