Alternative navigation in underwater environments is essential to prevent accumulating drift error of dead reckoning. In case of using an external positioning system, the installation and management process of the transmission station is cumbersome, and the operation range of underwater vehicle is limited. In order to solve this problem, navigation using geophysical information such as terrain, geomagnetic field and gravity can be used. Unlike the terrain, geomagnetic field and gravity are composed of 3-D information, so continuation process is required. In this paper, we present a integrated navigation algorithm using multiple geophysical information for long-term operation of UUV. The proposed algorithm is verified through numerical simulation in an artificially generated environments. As a result, integrated navigation showed higher navigation accuracy than single alternative navigation.

Abstract
1. 서 론
2. 수중 항법
    2.1 관성 항법
    2.2 지형 참조 항법
    2.3 지자기 대조 항법
    2.4 중력장 대조 항법
    2.5 복합 항법
3. 수치적 검증
    3.1 가상 환경 생성
    3.2 상태 변수 모델
    3.3 계측 모델
    3.4 시뮬레이션
4. 결 론
References

• 장준우(KAIST) | Junwoo Jang
• 조현근(KAIST) | Hyunkuen Cho
• 김진환(Mechanical Engineering, KAIST) | Jinwhan Kim Corresponding author
• 변승우(Hanwha Systems) | Seung-Woo Byun