Single frequency network (SFN) enables efficient use of spectrum by allocating the same frequency among multiple transmitters. In order to efficiently design and manage the SFN, the Advanced Television Systems Committee (ATSC) 3.0 physical layer standard has adopted transmitter identification (TxID) technology which allows to measure the individual and/or whole network channel response, such as power and time delay of the broadcast signal from transmitters. Since TxID is embedded into the host ATSC 3.0 frame as radio frequency (RF) watermark, it is transparent to legacy ATSC 3.0 receivers and only a specially designed TxID analyzer is able to detect it. This paper presents new TxID detection methods that improve the detection performance of ATSC 3.0 TxID signal by resolving the problems and limitation of the conventional TxID detection method. The superiorities of the proposed detection methods are verified through computer simulation, laboratory test, and field trial.