US Patent 9479894 Locating and tracking system

A locating and tracking system includes: at least one monitoring device; and a plurality of Bluetooth low energy (BLE) devices acting as either backbone nodes or tracking nodes. The backbone nodes are connected with each other and form a mesh network to relay information to the monitoring device in mesh mode so that the monitoring device knows all the backbone nodes' presence and locations. Each backbone node is further connected with a plurality of tracking nodes to form a sub-network. Within the sub-network, the backbone node is configured to operate in beacon mode to periodically check presence of all the tracking nodes and other compatible BLE devices within its coverage.