Abstract: Disclosed is a system for RFID indoor localization for estimating location of a target object in a localization area, comprising: a radio frequency identification (RFID) unit comprising a RFID reader and a plurality of RFID antennas in operative communication with the RFID reader; and a central unit in operative communication with the RFID unit. The central unit is capable of configuring and distributing a plurality of passive reference tags in the localization area and further capable of: collecting data from the passive reference tags through the RFID unit; processing the collected data; and estimating location of the target object. The central unit employs learning-based location estimation by received signal strength RSSI and detection rate fingerprinting of passive reference tags and the use of tags with different backscattered range.