前言

方向的獲得通過加速度感測器和磁力計共同完成。獲得方向和步數後，就可以初步得到慣性導航座標，再根據之前獲得的指紋法座標，兩者進行卡爾曼演算法，即可獲得較精確的座標。

方向獲取

由於博主最近比較忙，就不詳細介紹了。直接放個程式碼。

public class MainActivity extends AppCompatActivity implements SensorEventListener {

    private SensorManager sensorManager;
    private Sensor sensor_jia;
    private Sensor sensor_di;
 

    private TextView textView;


    private float[] jia_Values = new float[3];
    private float[] di_Values = new float[3];
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView=
 
findViewById(R.id.textview1);

        getSensorManager();
    }

    @Override
    public void onSensorChanged(SensorEvent event) {
        if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER)
        {                jia_Values = event.values;            }
        if (event.sensor.getType() ==
 
 Sensor.TYPE_MAGNETIC_FIELD)
        {                di_Values = event.values;            }
        calculateOrientation();


    }
    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {

    }
    public void getSensorManager() {
        sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);

        sensor_jia = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        sensor_di=sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
    }
    @Override
    protected void onResume() {
        super.onResume();
        if(sensorManager != null){

            sensorManager.registerListener(this,sensor_jia,SensorManager.SENSOR_DELAY_GAME);//延遲兩十毫秒
            sensorManager.registerListener(this,sensor_di,SensorManager.SENSOR_DELAY_GAME);
        }

    }

    @Override
    protected void onPause() {
        super.onPause();
        if(sensorManager != null){
            //解除註冊
            sensorManager.unregisterListener(this,sensor_jia);
        }

    }
    private void calculateOrientation()
    {
        float[] values = new float[3];
    float[] R = new float[9];
    SensorManager.getRotationMatrix(R, null, jia_Values,  di_Values);
    SensorManager.getOrientation(R, values);
    values[0] = (float) Math.toDegrees(values[0]);//轉換為角度
    if (values[0] >= -5 && values[0] < 5)
    {            textView.setText("正北");        }
    else if (values[0] >= 5 && values[0] < 85)
    {
          textView.setText("東北");        }
         else if (values[0] >= 85 && values[0] <= 95)
         {                    textView.setText("正東");        }
         else if (values[0] >= 95 && values[0] < 175)
        {                   textView.setText("東南");        }
         else if ((values[0] >= 175 && values[0] <= 180) || (values[0]) >= -180 && values[0] < -175)
         { textView.setText("正南");        }
         else if (values[0] >= -175 && values[0] < -95)
        {
          textView.setText("西南");        }
         else if (values[0] >= -95 && values[0] < -85)
         {                textView.setText("正西");        }
        else if (values[0] >= -85 && values[0] < -5)
         {                       textView.setText("西北");        }
           }






}