On-board orbit determination (OD) using directions of celestial bodies, planets and asteroids, in the Solar System for the Autonomous Navigation (AutoNav) is introduced in this paper. For deep space missions, OD has been performed by Range and Range Rate (RARR), which is a traditional ground tracking approach by radio waves. RARR enables the higher accuracy of OD than other methods. However, such radio navigation has the inevitable problems, such as strength reduction of radio waves and the transmitter limitation. Furthermore, people must stay and operate the spacecraft on the ground station, which makes the operating cost and burden considerable. Therefore, there has been a growing interest in the autonomy of the spacecraft in recent years to avoid the above-mentioned problems. This paper considers on-board OD using directions of celestial bodies from spacecraft. In particular, the selection of target bodies to observe is focused on because it's important that the selection of such target bodies leads to the satisfaction of mission requirements or increment of scientific observation. Then, this paper presents the method for the target selection, which is computationally cheap and makes the target selection easy.