フライバイカメラによる自律撮像に関する一考察

宇宙研 川口淳一郎、橋本樹明、中谷一郎、二宮敬虔



１９９６年打ち上げのPLANET-B探査機では、火星のグローバルな気象観測や光学航法実験を目的に
撮像カメラの搭載が計画されている。本報告は、このカメラを用いて火星の衛星である
Phobos,Deimosの撮影を検討したものである。特に航法精度が最終的に得られる光学分析能を
支配することを指摘するとともに、分解能の向上を図ることを目的にKalmanフィルタを用いた
簡単化された機上航法アルゴリズムを提案し、１分角という比較的低分解能の画像情報をもとにして
でも、再接近時を含めた連続撮影が可能であることを示す。

On Autonomous Imagery of Phobos and Deimos Using 

Flyby Camera on board PLANET-B spacecraft

by

Jun'ichiro Kawaguchi, Tatsuaki Hashimoto, Ichiro Nakatani and Keiken Ninomiya, 

Institute of Spacec and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 

229, JAPAN.

Abstract

ISAS (Institute of Space and Astronautical Science) is currently planning to launch 
PLANET-B spacecraft toward Mars in 1996, which is scheduled to be injected onto 300 km by 
10 rm (Martian Radii) elliptical orbit in September of 1997. Major purpose of PLANET-B 
mission is, first of all, plasma physics observation around the Mars whose interaction 
with solar wind as well as Martian intrinsic magnetic field is of great concern. 
In addition to it, as PLANET-B spacecraft is supposed to carry optical imaging instrument,
close-up imagery of Martian satellites, Phobos and Deimos is also planned. This optical 
camera 

has multi-functions comprised of optical navigation and long term meteorological observation and so on. However, high resolution imagery of Martian 

satellites inevitably requires quite a closest approach with those small objects and its resolution is almost governed by the navigation accuracy on which 

camera orientation sequence is to be based.

This paper presents a preliminary analysis of overcoming this difficulty by making use of autonomous, real-time and on-board navigator whose 

information source is optical imagery of those satellites. The results obtained here show that radio metric navigation solution in combination with Martian 

satellites ephemeris will not help in orientating camera direction correctly and out of practical use, but that autonomous navigation aid is quite efficient and 

satisfactory to take a close-up picture of those satellites with simplified Kalman filter on board.