Removing Gravity from Accelorameter data

I am doing some behavioral analysis on acceleration data of iPhone. I need to remove the gravity effect from the data. My data include The data that I have is in this format. [[NSDate date] timeIntervalSince1970], rawAccX, rawAccY, rawAccZ, rawRotX, rawRotY, rawRotZ, lat, lng, speed, course]; Can anybody help me how should I remove the gravity effect from my data? Thanksss

Answer 1

[bym]

you can remove the mean from the raw data. for example:

acc_x = rawAccX - mean(rawAccX);