Track to track fusion using out-of-sequence track information

Fusing out-of-sequence information is a very important problem for multi-sensor target tracking systems. The challenge is in dealing with measurements that arrive from the various sensors at a central processor out-of-sequence; that is, signals arriving with a measurement relating to a time previous to the time of the current state. The problem of how to deal with these updates has received much attention in recent years and has been solved optimally and sub-optimally by various authors. Most of the solutions, however, treated only the problem of updating a track by out-of-sequence measurements (OOSM), but did not deal with the updating of a central track by local tracks. In this paper we adopt three solutions proposed by Bar-Shalom, for the OOSM problem, and adapt them to solving the out-of-sequence track (OOST) problem. We then demonstrate their application to the case of track-to- track fusion.