Abstract: Services based on radio frequencies like GPS, RFID, GSM, CDMA, Wi-Fi or Bluetooth triangulation allows us to know, with some level of confidence, the position of a mobile device. However, those methods rely on special software and/or hardware. They also fail inside buildings since they cannot provide fine granulated values with a high level of accuracy. Each radio frequency device (mobile or not) emits a signal with a given strength and identification (Mac address or similar) to the air. The signal is captured by our nodes (at least 2 of the nodes), that measures the strength of the signal and therefore calculate the distance estimation. Since the signal is affected by electromagnetic noise, number of people in the building, or even temperature, the suggested system self corrects the values by knowing the distance between the nodes and measuring the signal strength. This gives to the system a very low error margin of about 1%.