Investigation of Screening Filter Methods to Enhance Computation Speed of Conjunction Assessment Analysis

The collision events in space result in generating a large number of fragmentation debris in orbit that threats to active satellites or spacecraft in near future. Currently, the space traffic management system analyzes the conjunction assessment to evaluate the collision risk of satellite by defining the time closest approach (TCA) and miss distance between two space objects to decide the collision avoidance maneuver plan of satellite when there is a high chance of collision. However, the computation time of conjunction analysis is the key to decide the collision maneuver plan to mitigate the collision risks because the conjunction analysis assessment algorithm without a filter spend huge runtime to detect the TCA of all space objects. In order to enhance the computation speed, the conjunction filter algorithms are very useful for finding the conjunction events of some objects before computing the precise TCA and miss distance. The timestep analysis is one of the keys to increase the computation speed. However, the filter possible miss some conjunction events. This paper presents the investigations of two conjunction filter methods: "Smart Sieve" and "CSieve" to define the conjunction events of three Thai satellites: THEOS, NAPA-1 and NAPA-2 by varying the timestep of both filters. The analyzed results (computation cost, number of conjunction events) are compared with the conjunction assessment analysis without filter.