www.sea-technology.com March 2015 / st 39
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nertial sensors are getting smaller, lighter and more
powerful. SBG Systems' (Rueil-Malmaison, France)
Ellipse series is a good example. It provides outstand-
ing accuracy for its size and cost.
Here, we compare the Ellipse to the Ekinox, a sur-
vey-grade inertial sensor released two years ago by
SBG, to determine which sensor to use for which appli-
cation. We will study if the Ellipse is accurate enough
to compensate for a sonar or echosounder.
The test survey discussed here was conducted by
CADDEN, a French distributor and integrator of hy-
drographic products, including inertial navigation sys-
tems. The aim of this survey was to evaluate the real-
time orientation and heave performance of the Ellipse and
Ekinox sensors in a typical marine environment.
Tested Sensors
The Ellipse Series is a line of miniature inertial sensors
that contains all essential elements for a cost-optimal solu-
tion: a miniature IMU, a high-performance processing unit,
and a single serial output interface (RS-232 or RS-422). The
products in the line are: a motion reference unit (MRU),
an inertial navigation system that can be connected to an
external GPS, and an integrated GPS/INS with one or two
antennas.
Miniature Versus Survey-Grade
Inertial Sensors
Comparing Test Performance Results of Ellipse and Ekinox Models
By Alexis Guinamard • Hélène Leplomb • Gilles Dandec
(Top) CADDEN's training survey vessel was used to
test the Ekinox and Ellipse sensors in France. (Bottom)
Bathymetric chart made by CADDEN with an R2Sonic
2024 multibeam sonar and an Ekinox-D inertial navi-
gation system, processed with QINSy software.