| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a time synchronization system for synchronizing local clocks of locating units, without using leased lines, networks, or expensive GPS receivers. <P>SOLUTION: Each of the locating units 120a and 120b receives a high-frequency (RF) signal 115 from a transmitter 110 at a known geographical location and measures the RF signal 115, to produce a respective measurement of the received RF signal and a respective timestamp of the measurement, recorded at substantially the same time, with respect to the local clocks of the locating units. A controller 150 determines a measured TDOA between the locating units by using the timestamps and measurements, computes time synchronization errors between the locating units from the difference between the measured TDOA and an expected TDOA, and provides a respective time adjustment to each of the locating units to offset the time synchronization error. <P>COPYRIGHT: (C)2007,JPO&INPIT |
