摘要 |
A method and apparatus for determining the synchronization and the position of terminals comprising of methods and apparatus for receiving a plurality of signals from opportunistic transmitters such as analog or digital radio/television broadcast and cellular tower signals; down-converting, sampling and processing such signals without requiring demodulation or detection of specific channel or timing features; re-transmitting the signals to another terminal or processing center; correlating the received and re-transmitted signals while generating estimates for differential ranging relative to each opportunistic transmitter and differential frequency and time synchronization offset for each pair of terminals; determining the position or coordinates of the at least two terminals using corresponding differential range measurements while using differential ranging measurements from three or more of such opportunistic transmitters. |