Linearity Tests of a Multibeam Echosounder

Samuel Greenaway
Master's Defense
CCOM/JHC University of New Hampshire
Friday, Sep. 10, 2010, 3:00pm
Chase 130

The backscatter information available from many modern multibeam echosounder systems (MBES) has been shown to be useful for a number of purposes.  Linearity of the system response is posited to be an important requirement for many backscatter processing techniques.  A procedure to measure the system linearity is developed for the Reson 7125.  These measurements are performed both in a controlled test tank environment and with systems installed on operational platforms.  The linearity of the system with respect to power, gain, and the returned signal level is evaluated.  We determine that it is possible to drive the system to nonlinear behavior.  The consequences of nonlinearity on both bathymetric measurements and backscatter intensity values are developed theoretically and tested against experimental observations. We find that nonlinear performance generally complicates and degrades both backscatter and bathymetric data products.


Sam Greenaway received a Sc.B. in Physics from Brown University in 1998.

Following forays into corporate finance, he joined the NOAA Corps in 2004 and has served on the NOAA Ship RAINIER conducting hydrographic surveys primarily in Alaska.

In his latest assignment, he oversaw the construction and outfitting of new hydrographic survey launches for the NOAA Ships RAINIER and FAIRWEATHER.

Sam received his master's degree in Earth Science/ Ocean Mapping in 2010.