Rate-gyro accuracy

Marco Trapanese · 2010-09-26T16:45:12+00:00

Hello,in the ADXRS614 datasheet I read:"CALIBRATED PERFORMANCEUsing a 3-point calibration technique, it is possible to calibratethe null and sensitivity drift of the ADXRS614 to an overallaccuracy of nearly 200°/hour. An overall accuracy of 40°/houror better is possible using more points."What does that mean?I don't understand the 200°/hour and 40°/hour values.I'm going to integrate the rate to obtain an heading. But I need an accuracy better than 2° per hour.Does the sentence above tell me that if I integrate the rate (let's assume with no noise...) after 1 hour I may have an error of about 200° ?I can't use a compass because there is a lot of iron in the nearby. I've already tried with a (calibrated) HMR-3000 with no chance.So I'm going to use a rate-gyro to have a relative heading, but I'm not sure if I can get the required accuracy over the time.Thanks for any hint.Marco

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Marco Trapanese 15 years ago

Il 27/09/2010 18:20, Tim Wescott ha scritto:

There are no tracks nor arms. I don't know exactly how it works, but the customer told me that key point.

Anyway, I ended up to a very poor tradeoff: I try to use the ADIS16130, which have a good resolution. I compensate for temperature (or better, I thermostat the device) and every x minutes (tbd) it requires a new reference point.

It doesn't solve the whole issue but it is a point to start. After prototyping I will decide to continue on this way or work on another project ;)

Bye Marco

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Tim Wescott 15 years ago

If it has no tracks or arms, and the customer is just _sure_ that it doesn't tilt by more than one or two degrees, then chances are high that you're working for the "see no evil" monkey.

Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html

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Marco Trapanese 15 years ago

Il 27/09/2010 20:08, Tim Wescott ha scritto:

That is what he told me.

I'm sorry... I don't understand what you're saying. I don't know this idiom :)

Marco

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Bill Sloman 15 years ago

He means that the customer is being over-optimistic about the amounbt of tilt.

The "see no evil" monkey is one of a set of three - he has his paws over his eyes. The other two are covering their ears and their mouth respectively.

-- Bill Sloman, Nijmegen

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Marco Trapanese 15 years ago

Il 27/09/2010 20:39, Bill Sloman ha scritto:

I'm pretty sure he (Jim) is right...

Oh yeah, there are the same three monkeys in Italian idioms too. Thank you for the clarification!

Marco

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Tim Wescott 15 years ago

That's got to be all over Europe and it's derivative cultures. I wonder if it isn't in China and/or Africa, too.

Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html

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Spehro Pefhany 15 years ago

Supposedly it originated in the far East (Japan)...

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Tim Wescott 15 years ago

Well, in Italy Syphilis was said to come from France -- but in France they said it came from Italy, and in Turkey they said it came from Christians!

Oddly enough, no one called it "our down-home disease".

So, origins must be checked carefully.

Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html

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Rich Grise 15 years ago

Where are the "Do no evil" Monkey's hands? ;-)

Cheers! Rich

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Spehro Pefhany 15 years ago

Sort of like "French letters" which were apparently called "English caps" in France?

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Michael A. Terrell 15 years ago

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That looks like the law firm of 'Dewey, Cheetem, & Howe'

Politicians should only get paid if the budget is balanced, and there is enough left over to pay them.

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Tim Wescott 15 years ago

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Hey! I used to work for those guys!

Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html

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krw 15 years ago

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In my case it's one three-faced guy!

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Rate-gyro accuracy

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