Improved weighting trilateral positioning method based on RSSI (received signal strength indicator) in wireless sensor network

The invention provides an improved weighting trilateral positioning method based on RSSI (received signal strength indicator) in a wireless sensor network and relates to the field of node self-positioning in the wireless sensor network. The method is used for solving the problem that a bigger positioning error is easily caused by the using of the traditional method which cannot meet the indoor positioning requirement in real life because the traditional method is limited by the factors such as signal multipath transmission, sight distance, low coordinate calculation precision, and the like. The method provided by the invention comprises the following steps: starting an unknown node positioning function and guiding an unknown node to send out a message; after receiving the message from the unknown node by an anchor node, calculating RSSI and storing in a hardware register; sending the ID number, RSSI value and position information (Xi, Yi) (i is equal to 1,2,...), which are distributed to the anchor node, to the unknown node by the anchor node; sequencing the anchor node according to the size of the received RSSI, and choosing N anchor nodes having big RSSI for self-positioning, wherein N is more than or equal to 3; according to the information of N anchor nodes, confirming the weighted value by the using of the trilateral positioning method; and using a weighting algorithm to calculate the coordinate of the unknown node. The method provided by the invention is used for weighting the coordinate information by utilizing the weighting principle.