An RSSI-based Wireless Sensor Node Localisation using Trilateration and\n Multilateration Methods for Outdoor Environment

Localisation can be defined as estimating or finding a position of the node.\nThere are two techniques in localisation, which are range-based and range-free\ntechniques. This paper focusses on the Received Signal Strength Indicator\n(RSSI) localisation method, which is categorised in a range-based technique\nalong with the time of arrival, time difference of arrival and angle of\narrival. Therefore, this study aims to compare the trilateration and\nmultilateration method for RSSI-based technique for localising the transmitted\n(Tx) node. The wireless sensor module in the work used LOng-RAnge radio (LoRa)\nwith 868MHz frequency. Nowadays, wireless networks have been a key technology\nfor smart environments, monitoring, and object tracking due to low power\nconsumption with long-range connectivity. The number of received (Rx) nodes are\nthree and four for trilateration and multilateration methods, respectively. The\ntransmitted node is placed at 32 different coordinates within the 10x10 meter\noutdoor area. The results show that error localisation obtained for General\nError Localisation (GER) for multilateration and trilateration is 1.83m and\n2.30m, respectively. An additional, the maximum and minimum error for\nmultilateration and trilateration from 1.00 to 5.28m and 0.5 to 3.61m. The\nstudy concludes that the multilateration method more accurate than\ntrilateration. Therefore, with the increasing number of Rx node, the accuracy\nof localisation of the Tx node increases.\n