SUNSTONE RTLS (Real-Time Locating System) provides online tracking of active devices called tags. Similar to GPS’s satellites we use anchors as reference nodes for the positioning. These anchors are installed on walls, ceiling, cable trays, etc. Like the satellites they need power, time synchronization that is addressed by a proprietary wired interface to the central unit. With SUNSTONE RTLS tracking of thousands of tags at ten thousands of square meters of area are practically achievable.