RF Geolocation

What is it?  

Radiofrequency (RF) geolocation is the process of calculating a transmitter’s location by using either the distance of the transmitter relative to a receiver or the angle (direction) of the transmitter relative to the receiver. Measurements from multiple receivers are subject to cross-referencing. 

How does it work?  

There are three ways to measure distance by leveraging the attributes of an RF signal. The first one is Received Signal Strength Indication (RSSI): the signal drops in strength with distance. 

The next method is called Time of Flight (ToF), or Two-Way Ranging (TWR). In this case, distance is determined by calculating the amount of time a signal travels from a transmitter to a receiver.  

Lastly, the Time Difference of Arrival (TDoA) technique is about figuring out the relative distance by comparing the difference in arrival time of a signal at 2 or more receivers. 

Angles are assessed in single or multiple dimensions. For instance, a 1-Axis Angle of Arrival (AoA) is the measurement of an angle by an RF signal’s arrival across an antenna array in one dimensional plane. On the other hand, a 2-Axis AoA involves multiple antenna arrays in 2 dimensional planes.