Design and implementation of a location awareness system for field police work

This paper presents a hand held location awareness device that enables police officers in the field to receive or send messages on the location of activities and events, and reach the destination quickly with the help of a detailed map. The design and development of the personal location awareness system is professionally and practically oriented. A simple but practical and user-friendly solution has been designed and implemented for the application environment of most Chinese cities. The system distinguishes itself from other vehicle carried GPS services for police in the following characteristics. First, a short message is the major communication medium. It can describe the dispatchment task clearly and quickly. Any photo taken at a scene can be sent back to the dispatch center as soon as the patrolmen arrive. The user needs no time to take notes and has no chance to misunderstand a command Second, a special software tool is developed to make a multi scale tiled image map for a hand held device, and a special map file format is established. By comparing to vector map, it is much easier to put into practice in a location based services (LBS) limited area. With the detailed maps of a labeled site, the basic requirement of location awareness can be met. Third, a text based message management system with restricted database operations is developed, which needs no DBMS in resident memory and makes all the application software run smoothly. The professional application of LBS needs three services. They are short message service of a public wireless communication system, GPS civil signal, and the dispatch message from police dispatch center with the help of a GIS system. The popularization of GPS embedded cell phone makes this kind of personal location aware application more cost effective and affordable for police bureaus. The proposed system has been put into practical use in a few municipal public security bureaus in China.