Regarding BMA-150 Acceleration sensor

At present i am working on hal part of sensors in android sdk, we are开发者_Go百科 using 3- Axis BMA-150 Accelerometer sensor to get acceleration values with respect to X,y,Z Axis, I want to know whether this sensor will give o/p directly in SI units by using some calibration techniques or what ? , and i noticed that in sensor.c file they mentioned

720.0 LSG = 1G(9.8 m/s2), what is the relation between LSG and acceleration due to gravity? what is meant by LSG

why they are multiplying the o/p of accelerometer x,y,z valuse with 9.8/720.0f . please help on this part .

Thanks Vinay

Without knowing anything about the device, 9.8 meters per square second is the value of gravitational acceleration at Earth surface. The equation you quote seems to be definition of "LSG" and the only thing that makes sense to define in the context is the unit in which output is provided. So the device will probably give output '720.0' on the axis that is vertical. By multiplying with 9.8/720.0 you renormalize the value to SI unit (m/s^2)

(Average gravitational acceleration, denoted G (that explains the 1G), is 9.80665 m/s^2, but varies by a few percent between equator and poles and the device is probably unable to give more than two significant digits precision anyway)