I’m trying to calculate the compass rotation in my viewmodel, The orientation data is provided by FusedOrientationProviderClient. Despite applying a low-pass filter to the azimuth value, the compass experiences drift when the device is moved quickly.

private val provider =
        LocationServices.getFusedOrientationProviderClient(context)

    fun requestOrientationUpdates(
        samplingDelay: OrientationOutputDelay = OrientationOutputDelay.MEDIUM,
        executor: ExecutorService = Executors.newSingleThreadExecutor(),
    ) = callbackFlow {
        val listener = DeviceOrientationListener {
            launch { send(it) }
        }
        val request = DeviceOrientationRequest.Builder(
            samplingDelay.toDeviceOrientationRequestDelay()
        ).build()

        provider.requestOrientationUpdates(
            /* request */ request,
            /* executor */ executor,
            /* callback listener */ listener
        )

        awaitClose {
            provider.removeOrientationUpdates(listener)
        }

    }

private fun calculateCompassRotation(
    location: Location,
    deviceOrientation: DeviceOrientation
): CompassState {
    val azimuthInDegrees = deviceOrientation.headingDegrees

    var bearTo = location.bearingTo(destLoc)
    if (bearTo < 0) bearTo += 360

    var direction: Float = bearTo - azimuthInDegrees
    if (direction < 0) direction += 360

    val isFacingDest = direction in 358.0..360.0 || direction in 0.0..2.0

    // Low-pass filter
    val alpha = 0.1f
    val smoothedDirection = currentDegreeNeedle + alpha * (direction - currentDegreeNeedle)
    currentDegreeNeedle = smoothedDirection

    val smoothedAzimuth = currentDegree + alpha * (azimuthInDegrees - currentDegree)
    currentDegree = -smoothedAzimuth

    val needleRotation = RotationTarget(currentDegreeNeedle, smoothedDirection)
    val compassRotation = RotationTarget(currentDegree, -smoothedAzimuth)

    return CompassState(
        isFacingDestination = isFacingDest,
        needleRotation = needleRotation,
        compassRotation = compassRotation
    )
}

I’ve tried testing with OutputDelay with both OutputDelay set to DEFAULT and MEDIUM.

Logs: https://pastebin.com/ivWjpTm2

After a fast movement, even if the user stops, the headingDegrees value seems to fall in the direction it was moving in before.