Specifications

Channel Master Operation Manual
P/N 95B-6001-00 (January 2005) page 125
------ G ------
Gimbals: Frame that will support the weight of an object but allow its free
rotation. Gimbals can be constructed to allow free rotation in one, two, or
three axes.
GO-DVL: DOS batch file used to configure a Navigator and start data col-
lection with Shiptrack.
Gyro: A rapidly spinning device mounted on gimbals to maintain a con-
stant orientation. These devices are commonly used to measure heading on
ships because, unlike magnetic compasses, they are unaffected by ferrous
metals or by varying electromagnetic fields. They can also be used to
measure pitch and roll because, unlike liquid level sensors, they are unaf-
fected by accelerations.
------ H ------
Homogeneity: The extent to which the current measured by all four beams
is the same. A key assumption of all ADCP processing is that the currents
are horizontally homogeneous across the four beams. This assumption is
checked for each measurement by using the error velocity measurement.
Horizontal ADCP (H-ADCP): Instrument designed to measure velocity
profiles in a horizontal plane.
------ I ------
Inertial Navigation: Method for estimating the attitude and position of a
moving platform (of primary interest here are AUVs) by integrating meas-
urements from gyros and accelerometers. This integration is subject to
large errors over time, so DVLs and pressure sensors are commonly incor-
porated as external inputs to measure and correct these errors.
------ J ------
------ K ------
------ L ------
Lag: A time delay between pulses or pings.
Long Ranger: Model name for Workhorse ADCPs of frequency 75 kHz.
Lowered ADCP (L-ADCP): Technique whereby one or two ADCPs are
lowered through the water column (typically on a rosette) to obtain veloc-
ity profiles over the full ocean depth. Note that a whole body of research
exists on how to properly remove the motion of the rosette from the veloc-
ity measurements obtained in this manner.