Cross measurement process with a ZigBee sensor network

Location systems based on Wireless Sensor Networks (WSN) and Receiver Signal Strength (RSS) mainly depend on how the measurements are obtained. Usually, there are some mobile nodes to be located that periodically send beacon frames, which are captured by an anchor sensor network. After combining this information, the system estimates node positions. However, it is well-known that these systems suffer from big inaccuracy problems due to environmental changes (obstacles, people, loose of line-of-sight, etc.), that produce fluctuations on RSS level. We introduce a cross measurement process to obtain more RSS data, getting information among the anchors and making possible to detect these changes, to perform appropriate fixes and calibrations.