Setting up mobile accelerometer data to account for phone rotation

Question

I want to record the data of a mobile accelerometer (x / y / z) and configure it for compatibility, regardless of the orientation / rotation of the phone. Usecase here is to record and normalize these parameters while driving, to detect turns / turns, etc. A key element of this is that the data obtained from the report does not depend on how the phone is oriented in the car. I use gyronorm.js to get information about the movement and orientation of the device.

I looked at the previous answers related to this topic on SO (for example, this one ) and tried to implement my approach to obtain the coordinates of the Earth.

However, I see that the readings completely change when I turn / twist my phone. Can someone tell me what I am doing wrong?

This is how I calculate the coordinates of the earth:

const deg2rad = Math.PI / 180; let alpha = gdata.do.alpha; let beta = gdata.do.beta; let gamma = gdata.do.gamma; let rotatematrix = this.getRotationMatrix(alpha * deg2rad, beta * deg2rad, gamma * deg2rad); let relativeacc = new Array(3); let earthacc = new Array(3); let inv = new Array(9) relativeacc[0] = gdata.dm.gx; relativeacc[1] = gdata.dm.gy; relativeacc[2] = gdata.dm.gz; //console.log ("FIRST MATRIX") mat3.invert(inv,rotatematrix); //console.log ("SECOND MATRIX") mat3.multiply(earthacc, inv, relativeacc); let accEarthX = earthacc[0]; let accEarthY = earthacc[1]; let accEarthZ = earthacc[2]; let aMag = Math.sqrt(accEarthX*accEarthX + accEarthY*accEarthY + accEarthZ*accEarthZ) console.log (`---RAW DATA --- ` + JSON.stringify(gdata)); console.log (`*** EARTH DATA X=${accEarthX}, Y=${accEarthY} Z=${accEarthZ}`) 

This is the code getRotationMatrix

 // credit:/questions/1247173/html5-get-device-orientation-rotation-in-relative-coordinate/3990824#3990824 getRotationMatrix(alpha, beta, gamma) { const getScreenOrientation = () => { switch (window.screen.orientation || window.screen.mozOrientation) { case 'landscape-primary': return 90; case 'landscape-secondary': return -90; case 'portrait-secondary': return 180; case 'portrait-primary': return 0; } if (window.orientation !== undefined) return window.orientation; }; const screenOrientation = getScreenOrientation(); console.log ("SCREEN ORIENTATIIN = "+screenOrientation); let out = []; let _z = alpha; let _x = beta; let _y = gamma; if (screenOrientation === 90) { _x = - gamma; _y = beta; } else if (screenOrientation === -90) { _x = gamma; _y = - beta; } else if (screenOrientation === 180) { _x = - beta; _y = - gamma; } else if (screenOrientation === 0) { _x = beta; _y = gamma; } let cX = Math.cos( _x ); let cY = Math.cos( _y ); let cZ = Math.cos( _z ); let sX = Math.sin( _x ); let sY = Math.sin( _y ); let sZ = Math.sin( _z ); out[0] = cZ * cY + sZ * sX * sY, // row 1, col 1 out[1] = cX * sZ, // row 2, col 1 out[2] = - cZ * sY + sZ * sX * cY , // row 3, col 1 out[3] = - cY * sZ + cZ * sX * sY, // row 1, col 2 out[4] = cZ * cX, // row 2, col 2 out[5] = sZ * sY + cZ * cY * sX, // row 3, col 2 out[6] = cX * sY, // row 1, col 3 out[7] = - sX, // row 2, col 3 out[8] = cX * cY // row 3, col 3 return out