msa.RdThis function is used to compute the Minimum Specific Acceleration (MSA). This is the absolute value of the norm of the acceleration minus 1 g, i.e., the amount that the acceleration differs from the gravity value. This is always equal to or less than the actual specific acceleration if A is correctly calibrated.
msa(A, ref)
| A | An nx3 acceleration matrix with columns [ax ay az], or a tag sensor data list containing acceleration data. Acceleration can be in any consistent unit, e.g., g or m/s^2. A can be in any frame as the MSA is rotation independent. |
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| ref | The gravitational field strength in the same units as A. This is not needed if A is a sensor structure. If A is a matrix, the default value is 9.81 which assumes that A is in m/s^2. Use ref = 1 if the unit of A is g. |
A column vector of MSA with the same number of rows as A, or a tag sensor data list (output matches input). m has the same units as A.
Possible input combinations: msa(A) if A is a list, msa(A,ref) if A is a matrix.
See Simon et al. (2012) Journal of Experimental Biology, 215:3786-3798.
sampleMatrix <- matrix(c(1, -0.5, 0.1, 0.8, -0.2, 0.6, 0.5, -0.9, -0.7), byrow = TRUE, nrow = 3, ncol = 3 ) msa(A = sampleMatrix, ref = 1) # Results: c(0.122497, 0.019804, 0.24499)