歳差運動する天体上ローバのための伝播時間計測による位置推定法

Abstract

A method to localize a rover on a small planetary body has been proposed based on measurements of the round-trip propagation delay between the rover and the mother spacecraft. It provides the accurate position of the rover by estimating the rotational parameters of the planetary body. It assumes that the rotational parameters of the planetary body are time invariant. Some planetary bodies may not satisfy this assumption. In this paper, the method has been expanded so that it can be applied to the rovers on planetary body with precessional motion. In order to express the precessional motion of the planetary body, the state vector and the equation for the time update are modified. Numerical simulations assuming the rover on Itokawa-size asteroid have been conducted. These results suggested that the expanded method can provide accurate position of the rover in case that the precessional period is longer than 25% of the rotational period.