The location accuracy is affected by different factors with the LANDMARC algorithm for Radio fre- quency identification (RFID). This study proposes an improved algorithm to calculate the coordinates of tracking tags. First
according to the distance from the nearest reference tag to the reader and its Received Signal Strength Indicator ( RSSI)
the distance from the reader to the tracking tags can be calculated by using of Lagrange interpo- lation method. Then
the coordinates of tracking tags could be obtained using trilateral position algorithm. The re- sults show that the accuracy of the proposed scheme increases by 65% compared with the original one and the mini- mum error deceases from 0. 39 m to 0. 0153 m. Based on experimental analysis
this scheme is very competitive in the indoor location sensing systems.