5G Positioning: Security and Privacy Aspects 287
The DOA estimation has been an active area of interest in the field of radar, sonar,
electronic surveillance and seismic exploration, and more recently of course in mobile
radio communication [65,116]. The estimation methods for DOA include spectral
estimation, minimum‐variance distortionless response estimator, linear prediction,
Figure 13.3 Principles of TOA, TDOA and AOA‐ based positioning: (a) Time of Arrival (TOA)
trilateration; (b) Time Difference of Arrival (TDOA) hyperbolic positioning.
AN 3
AN 1
AN 2
d 1
d 2
d 3
(a)
AN 1
AN 2
AN 3
Hyperbola:
d 1 -d 3 constant
Hyperbola:
d 1 -d 2 constant
d 2
d 1
d 3
(b)