An Autonomous Optical Guidance and Navigation Strategy in Flying-by Small Objects

Paper number

IAC-05-C1.8.08

Author

Mr. Kohta Tarao, University of Tokyo, Japan

Coauthor

Dr. Osamu Mori, Japan Aerospace Exploration Agency (JAXA), Japan

Coauthor

Dr. Junichiro Kawaguchi, Japan Aerospace Exploration Agency (JAXA)/ISAS, Japan

Year

2005

Abstract

Exploration of asteroids and small bodies recently intrigues a great deal of interest, since these planets are conceived to have preserved primordial state well. Institute of Space and Astronautical Science (ISAS) of Japan Aerospace Exploration Agency (JAXA) is currently investigating the flyby missions that observe the shape and the terrain of near-Earth objects. In order to accomplish the missions, an active orbit control guiding a spacecraft passing though the specified point in the B-plane around an object is required. It, at the same time, requests an autonomous navigation capability using onboard sensors such as optical cameras. 
A unique algebraic filter was devised and applied to the Martian probe ‘Nozomi’ launched in 1998 for the purpose of taking close-up images during high speed fly-bys with Phobos and Deimos. In the mission, the probe was designed to determine the orbital properties and would have enabled the spacecraft to take pictures of them. However the guidance, namely the orbital control, was not incorporated in the filter and only the navigation function was programmed aboard. 
In this paper, an integrated guidance and navigation strategy during high speed flyby is described. In general, it is impossible to determine the relative orbit during fly-by only with optical information due to the so called scaling effect in ballistic flight. And usually the optical navigation needs combined with the radio navigation that should provide the relative velocity vector information. This paper discusses first the new integrated guidance and navigation strategy, provided the relative velocity vector between the probe and the object is obtained. The paper presents next how the full orbit parameters are reconstructed even based only on the optical measurements. The velocity corrections aiming at the guidance help the navigation fully performed by also helping the observability enhanced.
The paper finally presents the experiment for the integrated guidance and navigation strategy, utilizing a falling pebble. In the experiment, the touchdown point of a pebble is estimated by the above mentioned method, which quickly moves the catcher to the aimed point automatically via real-time image processing.

Abstract document

IAC-05-C1.8.08.pdf

Manuscript document

IAC-05-C1.8.08.pdf (🔒 authorized access only).

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