Improved tracklet association for space debris using short-arc optical measurements

Initial orbit determination (IOD) for space debris is challenging, especially in the case where only optical observations, i.e. angles-only observations, are available and the optical observing arc is very short (i.e. too-short arc problem). The IOD solution to the too-short arc problem can be obtained using several short arcs of observations, or tracklets, from the same target, making it necessary to associate tracklets to targets across varying time intervals. The initial value problem (IVP) approach is a commonly used tracklet association method, but its accuracy and efficiency still has room to be improved. In this study, an improved IVP approach that determines the association by searching for the global minimum of a new loss function defined in canonical space is proposed. The use of the new loss function overcomes the problem of the multi-modal optimization in IVP for more accurate association. The proposed method was tested using real optical data collected from the Mt. Stromlo observatory. Results illustrated that the new method achieves 12% false negative and false positive rates which is better than 24% by the original IVP method. Additionally, the computational time is also reduced by the new method.