<P> Radiolocation is also used in cellular telephony via base stations . Most often, this is done through trilateration between radio towers . The location of the Caller or handset can be determined several ways: </P> <Ul> <Li> angle of arrival (AOA) requires at least two towers, locating the caller at the point where the lines along the angles from each tower intersect </Li> <Li> time difference of arrival (TDOA) resp . time of arrival (TOA) works using multilateration, except that it is the networks that determine the time difference and therefore distance from each tower (as with seismometers) </Li> <Li> location signature uses "fingerprinting" to store and recall patterns (such as multipath) which mobile phone signals are known to exhibit at different locations in each cell </Li> </Ul> <Li> angle of arrival (AOA) requires at least two towers, locating the caller at the point where the lines along the angles from each tower intersect </Li> <Li> time difference of arrival (TDOA) resp . time of arrival (TOA) works using multilateration, except that it is the networks that determine the time difference and therefore distance from each tower (as with seismometers) </Li>

What uses radio waves to find an object location