www.impactsubsea.com
Innovative Underwater Products
7.3 Heading, Pitch & Roll
In addition to Altitude, the ISA500 provides Heading, Pitch and Roll readings.
These readings are provided by a Micro-Electro-Mechanical System (MEMS)
sensor within the unit.
Traditionally MEMS sensors were not particularly accurate, however they have
significantly advanced in recent years. This advancement has made them ideal
components to be implemented into various pieces of equipment (if you have a
smart phone, the chances are that it has a built in MEMS sensor to provide you
with a Compass (Heading) and spirit level (Pitch/Roll).
The ISA500 makes use of accelerometers, gyroscopes and magnetometer data
fused in a digital algorithm to provide heading, pitch and roll to an accuracy level to
suit basic ROV/AUV navigation.
7.4 Temperature
A final reading which the ISA500 provides, is Temperature. The ISA500 makes use
of a temperature sensor, which sits against the ISA500 end cap (the end with the
connector).
This reading can be used for reference, or to alter the speed of sound value used by
the ISA500. As the temperature of the water will influence the speed of sound, it is
important to adjust for this to enable accuracy of measurements to be maintained.
© Impact Subsea Ltd
31
