Bi-directional Indoor Positioning System Research Based On ZigBee Wireless Network

With the arrival of information age, Internet of things, wireless sensor network (WSN) gradually step into our daily life. Wireless sensor network, with its huge number of network nodes, self-organizing network, low power consumption, short distance wireless connections, and many other advantages is widely used in smart homes, smart meters, medical care, environmental monitoring and so on. ZigBee technology as the support of the Internet of things, also has been widely used.Nowadays, to determine the actual location of the user or item at any time has become an important information service, outdoor positioning technology has been developed maturely, provides convenient and accurate indoor location services will become the focus in the future. With the continuous development of the Internet of things technology, the establishment of a wireless sensor network will be more and more widely, we can use the ZigBee network without any additional hardware devices for the design of indoor positioning system, which the direct use of ZigBee network gateway, routing equipment and extra mioving nodes can be realized very convenient. By designing the corresponding algorithm can achieve high precision positioning result, this article selects ZigBee technology as the carrier of this location based service, put forward a bi-directional indoor positioning systems based on ZigBee network, extending the ZigBee positioning method from passive monitoring type to moving node self-positioning.On the basis of the theoretical research we used the TI company CC2530chipset to develop bi-directional positioning system hardware devices, including moving node, reference node, and coordinator.Combined with complex indoor environment and the requirements of location accuracy I put forward a kind of location fingerprint database algorithm based on path loss model, this method greatly saved the time of fingerprint database establishment. Combining with the actual measurement way to establish fingerprint, the database establish and update is very convenient and in guarantee the positioning precision at the same time. Experiments in different environments show that use the limited area adjacent algorithm, the limited area weighted adjacent algorithm, limited area Bayesian algorithm proposed in this paper to calculate the user’s location, the average positioning error can be limited within1.5m in the optimal conditions.