SonTek/YSI Argonaut-XR Technical Manual - HydroScientific West

SonTek/YSI
The battery housing has three threaded inserts on
the bottom of the housing for easy installation.
The bolt pattern on the bottom of the battery
housing is shown in Figure 16. The threaded
inserts use ¼”-20 bolts; no more than ½” of
thread should be engaged to avoid damage to the
housing. The system includes bolts that are the
correct length for use with the mounting plate
included with the system.
To reduce magnetic interference of the batteries
with the compass/tilt sensor, the battery housing
should be no closer than 12 cm (5 in) from the
Argonaut. The mounting plate included with the
system places the housing at this distance.
Whenever using batteries near the Argonaut, you
should perform a compass calibration before
each deployment; the calibration should be
performed each time the battery pack is changed.
See §4.4 for details on compass calibration.
6.4. Argonaut Coordinate System
The Argonaut supports three coordinate systems for velocity data: ENU (East-North-Up), XYZ,
and BEAM. The coordinate system setting is determined in the setup menu of the real time
software (see the Argonaut Software Manual) or using the “CoordSystem” command from the
direct command interface (§3.8).
ENU (East-North-Up) coordinate system
For systems with the optional compass/tilt sensor, velocity can be recorded in ENU (East-North-
Up) coordinates. Using the ENU coordinate system allows the Argonaut to report velocity data
independent of instrument orientation (within limitations – see §4.3).
Using the ENU coordinate system also allows the Argonaut MD to vector average pings within
each sample (using updated compass/tilt information). If the Argonaut MD orientation changes
during the averaging interval, velocity data will still reflect the true water velocity. When using
the XYZ or BEAM coordinate system, velocity data can be corrupted if the Argonaut MD
orientation changes during the averaging interval. For the Argonaut MD, SonTek recommends
using the ENU coordinate system except for specialized applications by experienced users.
For the Argonaut XR, we assume that the installation is stationary and does not perform a vector
average of velocity data on a ping-by-ping basis. Data from the compass/tilt sensor are sampled
once at the beginning of the averaging period. The Argonaut XR is typically mounted on the
bottom, and the orientation changes only minimally during a deployment. We recommend using
the ENU coordinate system for most applications with the Argonaut XR.
The Argonaut SL does not normally include a compass/tilt sensor, and velocity data are normally
recorded in the XYZ coordinate system (see below). When using the ENU coordinate system, be
sure that the compass installation matches the hardware orientation setting. See §4.2 and §5.1 for
details.
66
Bolt pattern radius =
6.16 cm / 2.42 in
120 deg
120 deg
120 deg
Figure 16 – Argonaut XR/SL Battery
Housing Mounting Bolt Pattern
Argonaut Operation Manual Firmware Version 7.9 (May 1, 2001)