Hi Sumeet

For RFID localization, main methods leverage phase based localization in COTS

RFID reader Impinj R420 that can extract phase information. Recent works are based on Hologram, SAR, phase difference for tracking location and 3D Orientation.

References:

Tagoram: Real-time Tracking of Mobile RFID Tags to High Precision Using COTS Devices.

Rf-iDraw: Virtual Touch Screen in the Air Using RF Signals

Dude, where’s my card?: RFID Positioning That Works With Multipath and Non-Line of

Sight

See Through Walls with COTS RFID Systems!

Gyro in the Air: Tracking 3D Orientation

of Batteryless Internet-of-Things

Relative Localization of RFID Tags Using Spatial-Temporal Phase

Profiling.

You can check Dr. Lei Yang's github with open sources for RFID localization: "https://github.com/tagsys?tab=repositories"

Hey Sumeet, 

You're probably familiar with this approach, but I find it pretty elegant:

http://ieeexplore.ieee.org/document/7349142/

Thank you for your references and suggestions!