Spacecraft orbit determination enhancement by using low-altitude planetary optical images

A novel technique for trajectory determination of planetary orbiters by using optical images of the planetary surfaces, in addition to standard radiometric observables, is proposed and tested with some preliminary results. The methodology is based on relating two sequential views of the same scene of the planetary surface in a mathematical form exploiting fundamentals of homographic projections. The characteristic features selected in sampled images and used in the described method are corner points. These features are matched between two sequential views of the same scene of the planetary surface sampled by the camera. In order to test the feasibility of this method, a simulation framework is developed: it allows to generate synthetic images of the planet surface according to the orbiter position and orientation. A synthetic Digital Elevation Model (DEM) is generated and rendered by a ray tracing software according to the orbiter pose and camera parameters. The pattern matching algorithm is then applied to the generated high resolution images to test the proposed method in a realistic scenario. Preliminary results are presented by means of a simple orbital model implementation where the main geometries and constraints of BepiColombo’s Mercury Planetary Orbiter are taken in account, and simulated Doppler and optical observables are used in a simplified scenario.