SonTek/YSI Argonaut-XR Technical Manual - HydroScientific West

Figure 17 – ARGCHECK Output – Near Boundary Operation
SonTek/YSI
The top of the screen shows the minimum signal strength value observed for each beam. To
measure the noise level in each beam, run the system with the transducers in the air and look at
the minimum signal strength levels shown at the top of the screen.
Figure 17 shows the output of ARGCHECK from an Argonaut SL deployed looking down with the
transducers about six meters from the bottom.
In Figure 17 the bottom reflection can be clearly seen at a range of about 6 m. Following the
bottom reflection, the signal strength rapidly drops down to the system noise level. It remains at
this level for most of the rest of the profile. The small variations at a range of 12-14 m are caused
by multiple bottom reflections.
7.2. Deployment Site Survey
Surveying the deployment site is typically only done for the Argonaut XR and SL, and is not
required for the Argonaut MD. There are two main goals of a deployment site survey. First is to
verify that the system is not seeing interference underwater structures, deployment lines, or
boundaries. Second is to set the limits of the measurement volume based upon the environment.
Acoustic interference
It is important that the Argonaut does not see any interference from underwater objects whose
reflections may contaminate the acoustic return signal (and hence affect velocity data). These
objects may be underwater structures, boundaries (surface or bottom), or smaller items such as
deployment lines and cables.
Argonaut Software Manual (March 1, 2001) 61