Figure 4
From: Experimental verification of seafloor crustal deformation observations by UAV-based GNSS-A
(A) Location of the SAGA site. (B) Comparison between the planned survey line and actual observation track on November 8, 2022. Red and blue lines indicate the planned and observation tracks, respectively. Black squares indicate the locations of the four seafloor stations. (C) Example of an actual signal. The two-way travel time was measured from the time difference between the transmitted signal (red line) and the received signal (blue line). This is a case of continuous transmission for west, north, and east stations from near the centre of the observation site. The vertical axis is the voltage, which has been normalized by adjusting the gain of the physical oscillation of the sonar. Since acoustic sonar applies Auto Gain Control (AGC) during reception, the actual voltage value is unknown.
