PO/GO 연계기법을 이용한 RCS 해석코드 개발

다국어 초록 (Multilingual Abstract)

In the recent years, the combat survivability that measures the capability of performing a mission in hostile environment becomes a critical issue in the development of flying vehicles. An enhancement of survivability in the preliminary design can be achieved by the radar frequency (RF) stealth technique which intends to avoid an enemy’s radar. The level of the RF stealth is measured by introducing the so-called radar cross section(RCS).
There are several methods to compute radar cross section(RCS) such as geometrical optics (GO), physical optics (PO), method of moments (MM), and full equation method. In principle, the full Maxwell equations can be solved by the method of moments, finite element method (FEM), and finite volume time domain (FVTD) method. On the other hand, for the high frequency there exist various approximate methods; for example, physical optics and geometrical optics. Since the physical optics and the geometrical optics are dealt with a limited part of scattering and diffraction, these methods are very efficient in calculating the RCS of complicated shapes like an aircraft.
In this study, a hybrid method of physical optics and geometrical optics was employed in order to predict the RCS of flying vehicles for proper RCS reduction schemes. An in-house code using MATLAB was developed and validated with a simple model of cylinder, wing section and plate. In addition, RCS analysis of a flying vehicle was performed using a hybrid high-frequency electromagnetic scattering method based on physical optics and geometrical optics theories. In cavity return, the rays are assumed to bounce from the inlet cavity based on the laws of geometrical optics and to exit the cavity via the aperture. In other parts of a flying vehicle, the physical optics method is applied to compute the back-scattered field from the solid surface.

목차 (Table of Contents)

• Ⅰ. 서 론 1
• 1. 연구목적 및 배경 1
• 2. 연구방법 2
• Ⅱ. 본론 3
• 1. Stealth technology 3
• 1) 근거리 탐지(IR 스텔스) 3
• 2) 원거리 탐지(RF 스텔스) 4
• 2. 레이더 단면적 이론 6
• 1) 항공기 생존성과 RCS 6
• 2) 전자기파(Electromagnetic waves) 7
• 3) 레이더 포착 면적의 정의 및 특성 8
• 4) 레이더 레인지 방정식(Radar range equation, RRE) 10
• 5) 레이더 포착 면적 예측기법 14
• 2. RCS 감소 기술현황 16
• 1) 형상화 (Shaping) 16
• 2) 레이더 흡수재 17
• 3. RCS 예측 코드 20
• 1) 물체의 형상구현 및 좌표 20
• 2) Physical optics approximation 22
• 3) Geometrical optics approximation 25
• 4) Scattered field calculation 27
• 5) 해석코드(GNUPOGO) 구성 30
• 4. 예측코드 검증 및 비행체 RCS 해석 36
• 1) PO 기법 검증 36
• (1) 구형상(Sphere) 해석 36
• (2) 날개 단면(Wing section) 해석 37
• (3) 단순 비행체 해석 38
• 2) GO 기법 검증 38
• (1) 평판(Plate) 해석 38
• (2) Cavity 해석 40
• 3) PO/GO 기법 검증 42
• 4) 비행체 RCS 해석 44
• Ⅲ. 결론 47
• 참고 문헌 48