Rotational Status Inversion of Asteroids Based on Ellipsoidal model

Optical telescopes and ground-based radar are essential tools for celestial object detection. Optical data can be used to infer the rotational characteristics of asteroids but cannot provide small-scale three-dimensional shapes of asteroids. Ground-based radar can offer high-resolution delay-Doppler images, allowing for the reconstruction of small-scale asteroid structure and rotational characteristics. However, this inversion method relies on initial values provided by optical measurements regarding the rotational state. For asteroids without long-term accumulated optical data, the parameter range to be inverted increases dramatically with existing methods. Moreover, due to significant parameter coupling, the inversion accuracy significantly decreases. To address this issue, we propose a method for initializing rotational parameters using ellipsoidal shape representation in the absence of optical data. We apply the PSO optimization algorithm and validate the effectiveness of this method through numerical simulations.