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Re: Sensors in Motion Launches MEMS-Based Inertial Nav System

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  Re: Sensors in Motion Launches MEMS-Based Inertial Nav System kefischer <emoneyjoe@iglou.com> - 2015-07-26 15:40 -0400
    Re: Sensors in Motion Launches MEMS-Based Inertial Nav System wobbly <wobbly@dont-email.me> - 2015-07-28 22:14 +0000

#358746 — Re: Sensors in Motion Launches MEMS-Based Inertial Nav System

On Sun, 26 Jul 2015 18:19:24 +0000 (UTC), Fritz Köhler
<fritzk@notrenetwork.net> wrote:

>jimp wrote:
>
>>> A 3d magnetic sensor has no drift (pole position fixed). Likewise an 3d
>>> accelerometer (gravity is always down). In case of whatever drift due
>>> to whatever reason, that's why the need of ON-SITE calibration.
>> 
>> All inertial navigation systems suffer from integration drift which
>> means the position must be periodically corrected from something else.
>
>Not the magnetic. If you rotate 360° in whatever direction, the 
>orientation of the magnetic line will stay fixed. Its magnitude (Earth) 
>may vary around 0.5 gauss, but this is not an issue. (0.25 to 0.65 gauss 
>around the world)
>
>The accelerometer use to have a bit of drift, however, the gravity 
>direction line is again, still fixed. (the dis-alignment of the axis are 
>specified by the manufacturer)

         Moron NYM-changing TROLL, the magnetic pole is presently
somewhere in Northwest Canada, which is a different direction for
everybody on Earth.

         IMU components are readily available, but are useless
for navigation.
         The US Army Air Force in WWII had a device with
inputs from gyros, pitot tube airspeed, barometric pressure
and compass heading, but the longer the trip, the more
it could be off.

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#358944

kefischer wrote:

>>Not the magnetic. If you rotate 360° in whatever direction, the
>>orientation of the magnetic line will stay fixed. Its magnitude (Earth)
>>may vary around 0.5 gauss, but this is not an issue. (0.25 to 0.65 gauss
>>around the world)
>>
>>The accelerometer use to have a bit of drift, however, the gravity
>>direction line is again, still fixed. (the dis-alignment of the axis are
>>specified by the manufacturer)
> 
>          Moron NYM-changing TROLL, the magnetic pole is presently
> somewhere in Northwest Canada, which is a different direction for
> everybody on Earth.

:) Does not matter where it is. The point is that the position of the pole 
does not change significantly enough (to be measurable) over a time period 
of days or hours. Ie is been said, rotating your sensor 360⁰, where do you 
think it will arrive exactly (at the end of that rotation)?

>          IMU components are readily available, but are useless
> for navigation.

Too bat you know nothing about anything.

>          The US Army Air Force in WWII had a device with
> inputs from gyros, pitot tube airspeed, barometric pressure and compass
> heading, but the longer the trip, the more it could be off.

Only because of the gyros (drift), as is been said, having no natural axis 
of reference. Use a brain, big mouth.

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