我有一个非常恼人的问题，像一个指南针AR视图。所以，当我拿着手机在纵向（使画面指着我的脸），然后我叫 remapCoordinateSystem 的间距为0时，持有其肖像。然后方位角（指南针功能）是完美的，但只要我倾斜手机的方位被毁了，如果我向前弯曲方位增加，如果我向后弯曲则减。

I'm having a really annoying problem with a AR view acting like a compass. So when I hold the phone in portrait (so that the screen is pointing to my face), then I call the remapCoordinateSystem that the pitch is 0 when holding it portrait. Then the azimuth (compass functionality) is perfect, but as soon as I tilt the phone the azimuth gets ruined, if I bend forward the azimuth increases and if I bend backwards it decreases.

我用2个传感器，以获取读数， Sensor.TYPE_MAGNETIC_FIELD 和 Sensor.TYPE_GRAVITY 。

I use 2 sensors to get the readings, Sensor.TYPE_MAGNETIC_FIELD and Sensor.TYPE_GRAVITY.

我用的lowpassfilter是pretty的基础，它的实施与字母的常数，直接从传感器上使用的读值。

I use a lowpassfilter which is pretty basic, it's implemented with an alpha constant and is used directly on the read values from the sensors.

下面是我的code：

float[] rotationMatrix = new float[9];
SensorManager.getRotationMatrix(rotationMatrix, null, gravitymeterValues,
    magnetometerValues);

float[] remappedRotationMatrix = new float[9];

SensorManager.remapCoordinateSystem(rotationMatrix, SensorManager.AXIS_X,
    SensorManager.AXIS_Z, remappedRotationMatrix);

float results[] = new float[3];
SensorManager.getOrientation(remappedRotationMatrix, results);

float azimuth = (float) (results[0] * 180 / Math.PI);
if (azimuth < 0) {
    azimuth += 360;
}

float pitch = (float) (results[1] * 180 / Math.PI);
float roll = (float) (results[2] * 180 / Math.PI);

正如你看到的也没有神奇的在这里。我称这片code当gravitymeterValues​​和magnetometerValues​​是随时可以使用。

As you see there is no magic here. I call this piece of code when the gravitymeterValues and the magnetometerValues are ready to be used.

我的问题是如何阻止方位角从快要疯了，当我倾斜手机？

My question is how do I stop the azimuth from going crazy when I tilt the phone?

我检查了谷歌一个免费的应用程序Play商店，北斗的到现在也没有解决这个问题，但我希望有一个解决方案。

I checked a free app on the Google Play Store, Compass and it hasn't solved this problem, but I hope there is a solution.

我心目中2解决方案：

请在AR视图只能在非常constrainted俯仰角，现在我有这样的事情间距＆GT; = -5安培;＆安培;间距＆LT; = 30 。如果这不是fullfilled显示给用户，询问他的画面/她的旋转手机的画像。

Make the AR view only work in very constrainted pitch angles, right now I have something like pitch >= -5 && pitch <= 30. If this isn't fullfilled the user is shown a screen that asks him/her to rotate the phone to portrait.

不知怎么用球场上燮preSS的方位，这似乎是一个pretty的设备，具体的解决方案，虽然，但当然我开放的建议。

Somehow use the pitch to suppress the azimuth, this seems like a pretty device-specific solution though, but of course I'm open for suggestions.

我还可以补充一点，我一直在寻找了几个小时，一个体面的解决办法，我还没有发现任何给我任何超过2更好的解决方案）在这里。

I can also add that I've been searching for a couple of hours for a decent solution and I haven't found any that has given me any better solutions than 2) here.

在此先感谢！

推荐答案

请一个历史平均出来，我不知道俯仰和横滚的正确跨pretation所以下面code是方位角只

Keep a history and average out, I do not know the correct interpretation of pitch and roll so the following code is for azimuth only

类成员

private List<float[]> mRotHist = new ArrayList<float[]>();
private int mRotHistIndex;
// Change the value so that the azimuth is stable and fit your requirement
private int mHistoryMaxLength = 40;
float[] mGravity;
float[] mMagnetic;
float[] mRotationMatrix = new float[9];
// the direction of the back camera, only valid if the device is tilted up by
// at least 25 degrees.
private float mFacing = Float.NAN;

public static final float TWENTY_FIVE_DEGREE_IN_RADIAN = 0.436332313f;
public static final float ONE_FIFTY_FIVE_DEGREE_IN_RADIAN = 2.7052603f;

onSensorChanged

onSensorChanged

@Override
public void onSensorChanged(SensorEvent event)
{
     if (event.sensor.getType() == Sensor.TYPE_GRAVITY)
     {
         mGravity = event.values.clone();
     }
     else
     {
        mMagnetic = event.values.clone();
     }

     if (mGravity != null && mMagnetic != null)
     {
          if (SensorManager.getRotationMatrix(mRotationMatrix, null, mGravity, mMagnetic))
          {
              // inclination is the degree of tilt by the device independent of orientation (portrait or landscape)
              // if less than 25 or more than 155 degrees the device is considered lying flat
              float inclination = (float) Math.acos(mRotationMatrix[8]);
              if (inclination < TWENTY_FIVE_DEGREE_IN_RADIAN 
                      || inclination > ONE_FIFTY_FIVE_DEGREE_IN_RADIAN)
              {
                  // mFacing is undefined, so we need to clear the history
                  clearRotHist();
                  mFacing = Float.NaN;
              }
              else
              {
                  setRotHist();
                  // mFacing = azimuth is in radian
                  mFacing = findFacing(); 
              }
          }
     }
}

private void clearRotHist()
{
    if (DEBUG) {Log.d(TAG, "clearRotHist()");}
    mRotHist.clear();
    mRotHistIndex = 0;
}

private void setRotHist()
{
    if (DEBUG) {Log.d(TAG, "setRotHist()");}
    float[] hist = mRotationMatrix.clone();
    if (mRotHist.size() == mHistoryMaxLength)
    {
        mRotHist.remove(mRotHistIndex);
    }   
    mRotHist.add(mRotHistIndex++, hist);
    mRotHistIndex %= mHistoryMaxLength;
}

private float findFacing()
{
    if (DEBUG) {Log.d(TAG, "findFacing()");}
    float[] averageRotHist = average(mRotHist);
    return (float) Math.atan2(-averageRotHist[2], -averageRotHist[5]);
}

public float[] average(List<float[]> values)
{
    float[] result = new float[9];
    for (float[] value : values)
    {
        for (int i = 0; i < 9; i++)
        {
            result[i] += value[i];
        }
    }

    for (int i = 0; i < 9; i++)
    {
        result[i] = result[i] / values.size();
    }

    return result;
}