STM32W108 Wireless sensor network node location technology

Use stm32w108 Wireless node to complete N based on received signal strength indication (RSSI:Received signalstrength Indication) Second, three-side centroid weighted positioning, the mobile nodes in real-time positioning, and the positioning results sent to the collection center. Figure 15.1 is the actual scene of the positioning experiment, all experiments are done indoors, using 9 nodes,1 mobile nodes,8 beacon nodes.

Figure 15.1. Locating the actual scene

Based on the simplemac protocol stack introduced in chapter VII, the program is changed and the code is changed in the following section:

File solar-system.c related content:

function Processrxpacket ():

/************************************************************************** Function Description: Parsing and decoding the received packets and performing different operations according to different types of packets, the packet information is stored in the structure variable rxData by the packet callback function. Input parameters: None Output parameters: None ***************************************************************************/ void Processrxpacket (void) { ...... // Check to determine the packet frame type, only the ft_data type is used in the code Switch (rxdata.packet[1]&0x7) { Case Ft_data: Rx_details (printf ("ft_data\r\n");) Packettype = (ft_data<<4); Break Case Ft_mac_command: Rx_details (printf ("ft_mac_command\r\n");) Packettype = (ft_mac_command<<4); Break Default Rx_details (printf ("Unknown frame type\r\n");) Goto stopprocessing; }; // determine if the data packet has PAN ID Information if ((rxdata.packet[1]&0x40)!=0x40) { Pkthassrcpanid=true; Srcaddroffset = 2; } // four different address types Switch (rxdata.packet[2]) { ...... } Rx_details ( if (Pkthassrcpanid) { printf ("src pan = 0x%04x\r\n", Srcpanid); } ) // determine if the packet length satisfies sufficient length to hold the payload type if (Rxdata.packet[0]<payloadstart) { Rx_details (printf ("Length byte Too short\r\n");) Goto stopprocessing; } // calculate packet type by frame type and load type Packettype |= (rxdata.packet[payloadstart]<<0); Rx_details (printf ("Packet type = 0x%02x\r\n", packettype);) // different packet types perform different operations Switch (packettype) { Case (Generic_data_packet):// normal type packet,Sun node and Planet node will receive Rx_details (printf ("generic_data_packet\r\n");) printf ("%d\n", Rxdata.rssi);//rssi output Break ...... Default Rx_details (printf ("Unknown payload type\r\n");) Goto stopprocessing; } Stopprocessing: rxdata.packetbeingprocessed = FALSE; }

function joincmd ():

/************************************************************************** Function Description:Planet broadcast search Sun node, complete join network Input parameters: None Output parameters: None *************************************************************************/ void Joincmd (void) { ...... #ifdef Planet_role autosendrate = 1;// set node to send packet frequency to Sun node, speed up frequency, calculate RSSI halsetled (LED_D4);// light LED4 #endif ...... }

This article is from "stm32w108 embedded wireless sensor network" Tie Qiu, Xiafeng, newcomer authoring . Tsinghua University Press , year 5 months

STM32W108 Wireless sensor network node location technology