Design of query language for tracking moving objects

Recently, the need for LBS (Location Based Services) is increasing due to the widespread of mobile computing devices (e.g. PDA, cellular phone, and notebook computer) and positioning technologies (e.g. GPS and RFID). In LBS, there are many applications that need to manage moving objects (e.g. taxies, persons). The trajectories or the positions of moving objects are displayed on the map by using GIS. However, it is hard to use GIS or traditional relational database systems to manage moving objects since they do not support proper and convenient query language. The previous studies suggested several query languages to retrieve moving objects. However, they do not propose DDL (Data Definition Language) and do not support full functions that are necessary. In this paper, we propose MOQL (Moving Objects Query Language) which is a convenient interface and tool for developers. MOQL has the following features. First, it supports DDL to insert/delete/update the positions of moving objects. Second, it can be used to retrieve the trajectories or the future positions of moving objects. Third, it defines several utility functions to manage spatial or temporal properties of moving objects. Keywords-LBS; query language; moving objects