An Internet-based, inverse-GPS system for monitoring and tracking mobile aquatic sensors

This paper presents a novel, Internet-based system designed for continual monitoring and tracking of mobile aquatic sensors. A general overview of current positioning and tracking techniques is presented. The paper then details the two facets of the proposed system: (1) the sensors and signal processing for positioning and monitoring; and (2) the Internet-based tracking. The signal processing system is comprised of hardware and software components needed to acquire and store the necessary information from ultrasonic beacon signals in a database. Hyperbolic multi-lateration algorithms solve the inverse-GPS problem using the received signals from multiple stations to position the sensor in 3-D, while simultaneously extracting the sensor´s unique ID along with any sensed information. The extracted information is time-stamped and stored in a database, which is accessed through a Web site. A server-side scripting language is used to dynamically create the chosen Web page, to process the data retrieved via SQL from the database, and to perform the tracking functions. The processed information may be viewed either as raw data or in graphical form.