|
|
|
|
|||||
|
||||||
Subject: Re: Fluxgate compass /low end US vendor
From: George Huxtable (george@XXX.XXX)
Date: Fri Feb 01 2002 - 10:47:06 EST
Brian Whatcott says-
>
>The low end of the market for a 3 axis magnetic sensor plus pitch and roll
>detection is probably this board level OEM module from Precision Navigation
>Inc.
>
><http://www.precisionnav.com/compass-sensors-radar-sensors-breath-sensors-a
>nd-oem-modules/sensors-modules.html#sensormodules>
>
>
>The tcm2-50 at $770, still is not bargain priced - and the magnetic
>sensors are not exactly flux gates, and the high dollar strap-down
>rate-sensors and acceleration sensors are replaced by two "electrolytic"
>inclinometers which read out pitch and roll to +/- 50 degrees, but this is
>a step in the right direction, I'd think.
============
George Huxtable replies-
Now that Brian is referring to "the high dollar strap-down rate-sensors and
acceleration sensors", it seems we are starting to agree about the
components that are really needed to put together a good fluxmeter for
surface use.
But I doubt if the instrument he refers to will take us even part of the
way there.
I presume (and please, someone correct me if I have it wrong) that an
"electrolytic" inclinometer uses a conductive liquid in a U-tube, with
electrical (or capacitive) connections making up two arms of a Wheatstone
bridge to detect departures from the level. Or something on those lines. If
so, this has exactly the same limitations as any other gravity-sensor when
it goes to sea. It's just as sensitive to the disturbances caused by the
sea-state accelerations. It will do no better than a damped gimbal or
pendulum or a 3-axis accelerometer.
So I expect that this instrument will suffer from the same limitations as
the others, in rough weather.
George Huxtable.
------------------------------
george@XXX.XXX
George Huxtable, 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
Tel. 01865 820222 or (int.) +44 1865 820222.
------------------------------
|