PATS architecture (see OV-1 Diagram) consists of multiple nodes distributed in a disaster site and wirelessly interconnected through a low-power ZigBee mesh network. The PATS ZigBee mesh network uses 2.4 GHz band which operates worldwide, with a maximum data rate of 250 kbps. ZigBee is chosen for PATS because it’s a low power, low cost, and open global standard technology wireless mesh network intended for monitoring and controlling applications. The PATS ZigBee mesh network is a decentralized network (similar to the Internet) consists of three types of nodes: coordinator, router, and end device nodes. The coordinator node initializes a network, and manages network nodes. The router nodes – Signal Posts - are always active and participate in the network by routing messages from the Personnel Locators to the Command Centers.
PATS ZigBee mesh network is formed with the following type of nodes:
Personnel Locator node (Field Agent/End Device): has a minimized user interface, RFID tag, RFID reader, RFID antenna, GPS receiver module, ZigBee RF module, accelorometer and temperature sensor. It is used by the filed agents.
Signal Post node (Data Router): has a minimized user interface, ZigBee RF, battery, and GPS reciever module and it provides location services to the Personnel Locator nodes. It also provides data routing services between the Personnel Locator nodes and the Command Center. PATS requires at least three Signal Post nodes to operate successfully.
Command Center(Mission Coordinator): Personnel data collection node which runs a Accountability and Tracking software that displays the disaster site map with personnel location, enviromental information and is used by the mission coordinators.