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2026 Vol.45, Issue 4 Preview Page
Comparison of monostatic acoustic scattering characteristics of active underwater target forms

능동 수중 표적 형상의 단상태 음향 산란 특성 비교

Jeong-Il Han1
,
Keunhwa Lee1*
,
Kookhyun Kim2
한 정일1
,
이 근화1*
,
김 국현2
1세종대학교 해양융합시스템공학과
2국립창원대학교 첨단방위공학대학원
*Corresponding Author
31 July 2026. pp. 387-399
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Abstract

Active sonar echoes are strongly influenced by target geometry and structural arrangement, and post-detection classification requires quantitative features that summarize such differences. Monostatic Target Strength (TS) provides the angular distribution of echo amplitude but has limitations in directly resolving the sources of variation associated with time delays, structural highlights, and phase interference. In this study, four active underwater target forms were configured as symmetric and contracted-stern case models under identical conditions, and their monostatic scattering characteristics were compared using frequency domain TS and time domain echo responses. Time domain echoes were visualized using aspect–time stack maps to examine the arrival times and relative contributions of highlights over azimuth. Integrated Target Strength (ITS), defined from time domain echo energy, was calculated, and ITS-based summary metrics were introduced, including sector-averaged ITS over the forward (0° – 30°), beam (80° – 100°), and aft (150° – 180°) sectors, the forward–aft contrast (ΔITS), and the Transition Fade Index (TFI), defined as the linear attenuation slope over the beam-to-stern transition sector (95° – 120°). Within the four model cases considered, the symmetric models exhibit relatively balanced ITS/TS distributions between the forward and aft sectors, whereas the contracted-stern models tend to show reduced ITS in the aft sector. In particular, TFI quantifies the attenuation trend from the beam aspect toward the stern and provides complementary information to the sector-averaged ITS and ΔITS, which primarily represent differences in aft scattering level. These results provide quantitative evidence for interpreting monostatic scattering characteristics of active underwater target forms using time domain energy-based metrics.

Keywords
Monostatic scattering
Target Strength (TS)
Time domain analysis
Integrated Target Strength (ITS)
Active underwater target form

능동소나 반향은 표적 형상과 구조 배치에 의해 크게 좌우되며, 탐지 후 분류·식별 단계에서는 이를 정량적 특징으로 요약·비교하는 과정이 요구된다. 단상태 표적강도(Target Strength, TS)는 방위각별 반향 크기 분포를 제공하지만, 시간 지연, 구조물별 하이라이트, 위상 간섭에 따른 변동 원인을 직접 분리해 해석하기에는 한계가 있다. 본 연구에서는 동일 조건에서 4개의 능동 수중 표적 형상을 대칭형 및 선미 수축형 사례 모델로 구성하고, 주파수 영역 TS와 시간영역 반향을 분석하여 능동 수중 표적 형상에 따른 단상태 산란 특성을 비교하였다. 시간영역 반향은 시간–방위각 스택맵으로 시각화하여 하이라이트의 도달시각 및 상대 기여 변화를 확인하였다. 또한 시간영역 에너지 기반 적분 표적강도(Integrated Target Strength, ITS)를 계산하고, ITS 기반 요약지표로 섹터 평균(전방 0° – 30°, 측방 80° – 100°, 후방 150° – 180°), 전·후방 대비(ΔITS), 그리고 beam–stern 전이 구간(95° – 120°)의 선형 감쇠 기울기(Transition Fade Index, TFI)를 정의하여 정량 비교를 수행하였다. 제시된 모델 조건에서 대칭형 모델은 전·후방에서 비교적 균형적인 ITS/TS 분포를 보인 반면, 선미 수축형 모델은 후방 구간에서 ITS 감소 경향을 보였다. 특히 TFI는 beam–stern 전이 구간의 감쇠 추세를 정량화하여, 섹터 평균 및 ΔITS가 제공하는 후방 산란 수준 차이를 보완하는 지표로 활용 가능함을 확인하였다. 본 연구는 제시된 4개 모델 조건에서 능동 수중 표적 형상 변화에 따른 단상태 산란 특성을 시간영역 에너지 기반 지표로 해석하는 정량적 단서를 제공한다.

키워드
단상태 산란
표적강도(Target Strength, TS)
시간영역 해석
적분 표적강도(Integrated Target Strength, ITS)
능동 수중 표적 형상
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Information
  • Publisher :The Acoustical Society of Korea
  • Publisher(Ko) :한국음향학회
  • Journal Title :The Journal of the Acoustical Society of Korea
  • Journal Title(Ko) :한국음향학회지
  • Volume : 45
  • No :4
  • Pages :387-399
  • Received Date : 2026-04-14
  • Accepted Date : 2026-06-29
  • DOI :https://doi.org/10.7776/ASK.2026.45.4.387
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