Positioning method and system based on Wi-Fi internet of things device network

A positioning method based on a Wi-Fi IoT device network, comprising:

• selecting a plurality of positioning monitoring nodes from nodes of any one subnet of the Wi-Fi IoT device network, wherein a subnet master node of the subnet is one of the positioning monitoring nodes;
• spatial position information of each of the positioning monitoring nodes and mutual physical distances between the positioning monitoring nodes are knowable;
• a positioning target device transmits a data packet corresponding thereto;
• each of all the positioning monitoring nodes in the subnet or all the other positioning monitoring nodes in the subnet except the subnet master node, respectively within an information receiving and transmitting range thereof, receives the data packet sent by the same positioning target device, records corresponding data packet receipt clock information, and provides the data packet receipt clock information and identification information of the positioning target device corresponding to the data packet to the subnet master node;
• and
• the subnet master node, according to information respectively provided by the plurality of positioning monitoring nodes, utilizes signal arrival time differences between the plurality of positioning monitoring nodes receiving the data packet from the same positioning target device to compute distance differences of the positioning target device with respect to the plurality of positioning monitoring nodes, and determines a position of the positioning target device in a physical coverage range of the subnet;
• wherein any one positioning monitoring node locally maintains a positioning target device MAC address list, and periodically updates the list through the subnet master node;
• the positioning monitoring node receives a Beacon packet sent by the positioning target device and supporting adjusting a transmitting period in MAC layer, and records a receipt time;
• when a MAC address in the Beacon packet representing a sender of the Beacon packet is in the positioning target device MAC address list of the positioning monitoring node, then the positioning monitoring node provides information to the subnet master node corresponding thereto;
• and
• wherein the information includes the MAC address of the sender of the Beacon packet, the receipt time of the Beacon packet, a receiving signal strength RSSI value of the Beacon packet, or includes the MAC address of the sender of the Beacon packet, the receipt time of the Beacon packet, a receiving signal strength RSSI value of the Beacon packet, and detected information obtained by a sensing and detection module of the positioning target device.