Symmetrical_double-sided_two-way_ranging
In radio technology, symmetrical double-sided two-way ranging (SDS-TWR) is a ranging method that uses two delays that naturally occur in signal transmission to determine the range between two stations:[1]
- Signal propagation delay between two wireless devices
- Processing delay of acknowledgements within a wireless device
This method is called symmetrical double-sided two-way ranging because:
- It is symmetrical in that the measurements from station A to station B are a mirror-image of the measurements from station B to station A (ABA to BAB).
- It is double-sided in that only two stations are used for ranging measurement – station A and station B.
- It is two-way in that a data packet (called a test packet) and an ACK packet is used.