NAVIGATION USING SERENDIPITOUS STAR-TRACKER OBSERVATIONS AND ON-BOARD DATA PROCESSING

A majority of spacecraft are equipped with star trackers to estimate their attitude. With the ever growing number of objects orbiting the Earth, these star trackers often serendipitously capture space objects in the images that they take to estimate the spacecraft’s attitude. This study aims to assess the feasibility of using these measurements in order to estimate the state of an observer spacecraft. To do so, the visibility of these space objects is analyzed as well as the performance of a navigation algorithm written to utilize these measurements. The study found that using serendipitous measurements of space objects is indeed feasible when the observer is in an orbit where there are a large number of space objects that are visible. Observers in low Earth orbits were shown to have success with this navigation algorithm. Observers in approximately geostationary orbits have a fairly limited number of space objects that are visible.