One-pass trajectory tracking in discs and beams

Trajectory tracking is a method that tracks the current position of a moving object and simplifies its trajectory. It combines two fundamental techniques of moving objects databases, i.e., position tracking and trajectory simplification, in one routine to avoid sending redundant trajectory data to the databases, such that the network, storage, and computing resources are saved. There are some distinct trajectory tracking algorithms, such as LDRH and GRTS. However, they still suffer from issues of effectiveness and efficiency. Moreover, they only track a moving object in discs and cannot satisfy the varied requirements of trajectory tracking in shapes beyond discs. To solve these problems, this paper presents two novel one-pass trajectory tracking algorithms, i.e., CITT and BITT, based on sector intersection and spatio-temporal cone intersection that effectively and efficiently track a moving object in discs and beams, respectively. Using four real-life trajectory datasets, we experimentally show that our CITT and BITT are feasible to track moving objects in discs and beams, respectively. The output sizes of CITT and BITT are comparable with GRTS, and they are 34.7% and 28.3% of LDRH, respectively. Besides, CITT and BITT are on average 151.8 and 88.5 times faster than GRTS, respectively.