Systems Engineering of Datacasting for Public Safety Vehicles

Public safety officers need current, accurate and complete information to maintain the security of their communities. Existing communications systems for public safety officers consist of analog and digital radios, supplemented with cell phone communications. Dispatchers with a need to broadcast information can only do so via voice. Small data packets can be exchanged via point-to-point methods with modern digital radios, but no data broadcast exists for public safety communications. Broadcasting images, audio and text to officers in the field will offer a better collection of information necessary to make critical, time-sensitive public safety decisions. Live updates to in-vehicle databases and computer systems will provide officers with critical, up-to-the-minute information. Working with New Hampshire Public Television and the National Institute of Justice, we are researching a system to utilize excess bandwidth available in the public television broadcast spectrum. The system is to be implemented using the onboard data and car management system known as Project54TM. The use of this excess bandwidth for the delivery of digital data in a one-way, high-speed, broadcast stream is called datacasting. While datacasting has existed since the initial draft ATSC standards defining digital television, few locations have installed full datacasting capabilities, and no other datacasting effort has implemented a mobile, two-way datacasting system. This paper will outline the design of the datacasting environment for the New Hampshire Department of Safety, the results of field tests performed by 10 State Police vehicles collecting data during routine public safety patrols, and the status of the two-way datacasting implementation.