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Set of three MEMS sensors creates location-placing solution

5/10/2011 05:44 PM EDT
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docdivakar
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re: Set of three MEMS sensors creates location-placing solution
docdivakar   6/24/2011 7:17:20 PM
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I am sure some one has figured out a MEMS version of Pitot tube to measure static air pressure which can alleviate the thermal concerns. MP Divakar

ROV ENG
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re: Set of three MEMS sensors creates location-placing solution
ROV ENG   5/17/2011 8:10:40 PM
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Etmax, that's correct but remember that calculating altitude from a barometric pressure is not very accurate due to a variety of factors beyond our control. The moisture contect in the air can cause a large measurement error as can the temperature gradient in the air column. It's not difficult to select a location and to design a mounting arrangement with low thermal resistance to the ambient air and high thermal resistance to the housing of the device, therfore resulting in small measurement error when compared to the other potential error sources.

Etmax
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re: Set of three MEMS sensors creates location-placing solution
Etmax   5/13/2011 8:29:16 AM
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Wikipedia says that altitude can be calculated from z=c\;T\;\log(P_o/P), where most importantly T= temperature and P_o is the pressure at sea level. Given that the temperature of a handheld device is more dependent on the person holding it and the pressure at sea level is more than likely not known, just how accurately can this determine your altitude?

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