CLOSED LOOP TRACKING SYSTEM

摘要

A closed loop tracking system accurately tracks targets by polling a mobile unit for positional data on a real-time and historical basis. The polled data is filtered and corrected before generating track candidates. The tracking system chooses the best candidate for displaying on a map. When the tracking system needs additional information to make the best candidate choice, the mobile unit is polled for the data necessary to make the correct choice, making the tracking system closed loop. The tracking system transmits digital positional data over the same voice channel that was established for voice communications with a tracking system call taker. This prevents the mobile unit from having to establish a second separate wireless data communication connection with the tracking system. Maps are used to identify the location of the tracked mobile unit. Better positional accuracy in latitude and longitude is provided by using measurement corrections from a variety of different sources in addition to the Global Positioning System and triangulation data.