Unit of Velocity from a Random Walk measured by an accelerometer

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The discussion centers on a Kalman filter measurement equation involving "-g + v," where g is acceleration in m/s² and v is a velocity random walk expressed in m/s/sqrt(hr). Participants highlight that the units of g and v are incompatible, indicating a potential error in the equation's derivation. There is a suggestion to reconsider the inclusion of the random walk in the measurement equation instead of the state propagation equation. The need for proper unit transformation to ensure accurate calculations is emphasized. Clarifying these unit discrepancies is essential for the correct application of the Kalman filter.
hoddy
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Hi, I am working on a kalman filter where my measurement equation involves "-g + v" , where g is in m/s^2 and v is velocity random walk given in m/s/sqrt(hr). Feels like a stupid question, but how can I transform the unit of velocity random walk so I can do the calculation correctly?
Hi, I am working on a kalman filter where my measurement equation involves "-g + v" , where g is in m/s^2 and v is velocity random walk given in m/s/sqrt(hr). Feels like a stupid question, but how can I transform the unit of velocity random walk so I can do the calculation correctly?
 
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hoddy said:
Summary: Hi, I am working on a kalman filter where my measurement equation involves "-g + v" , where g is in m/s^2 and v is velocity random walk given in m/s/sqrt(hr). Feels like a stupid question, but how can I transform the unit of velocity random walk so I can do the calculation correctly?

Hi, I am working on a kalman filter where my measurement equation involves "-g + v" , where g is in m/s^2 and v is velocity random walk given in m/s/sqrt(hr). Feels like a stupid question, but how can I transform the unit of velocity random walk so I can do the calculation correctly?
It looks to me as though you are trying to add quantities with incommensurate units. ##g## has units of acceleration, and ##v## has units that are neither velocity or acceleration. That suggests that there is an error somewhere in the derivation of the ##-g+v## term. Maybe you have assumed that some variable has a value of ##1##, and forgotten to carry along its units.
 
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Also, I wonder why you are including your random walk process in the measurement equation rather than in the state propagation equation?
 

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