Reliabilities for the technologies of position detection mean the measurement errors in the position detection. Presently, there are many different technologies used in position detection. But, as signal receiver operating in different locations are used to detect precise positions of objects located at long distances, it is hard to know when a object's or user's-terminal devices send a signal. In this case, the technology using the ToA (Time of Arrival) is impossibly unreliable, and the TDoA (Time Difference of Arrival) technology is the more suitable. If a TDoA-based electric surveillance system fails to achieve precise time-synchronization between devices for separation distance operation, it is impossible to obtain correct TDoA values from signals sent by signal receiver, and such a failure to obtaining the correct values directly affects location estimation error. In this respect, precise time-synchronization between signal receivers for separation distance operation is a core technology in detecting TDoA-based locations. In this paper the accuracy of the proposed and improved time-synchronization and measurement of error of TDoA-based location detection technology is evaluated, and, thus, TDoA-based location measurement error is greatly improved with the proposed method for time-synchronization error reduction.