A wireless sensor network (W SN) includes a series of nods , each of them containing some sensors which have a role in gathering data about the circuit in which they are distributed. Sensor networks enjoy variety of uses ; that is why they are attracted by many countries . In a wireless sensor network , few nods have already known their position which are called anchor node ; other nods must calculate their position accordingly . In this essay “ received signal strength indicator ” and “ Nero-Fuzzy ” are used in order to calculate unspecified - position nods ’ coordinate . Each unspecified - position node must know the position of some nearing anchor nodes . The more the nodes are , the more precise the coordinate is . In this essay , unspecified node ’ s coordinate is estimated according to two or more anchor nodes using logic fuzzy . Since the range covered by sensor networks is broad , finding all anchor nodes is a time - consuming task and needs a lot of memory . Therefore , distance limit between anchor nodes and unspecified nodes is considered . The area around anchor nodes and unspecified nodes is divided reticulated , and then , the unspecified node ’ s coordinate is estimated according to logic fuzzy rules . The estimated average error rate for 120 nodes using this method equals to 2 % of radio range , which is minimal in comparison to APS algorithm . پرونده مقاله