9-axis sensor fusion with Kalman filter

Add support for 9-axis gravity and linear-acceleration sensors
virtual orientation sensor using 9-axis fusion

Change-Id: I6717539373fce781c10e97b6fa59f68a831a592f
diff --git a/services/sensorservice/SensorFusion.h b/services/sensorservice/SensorFusion.h
new file mode 100644
index 0000000..c7eab12
--- /dev/null
+++ b/services/sensorservice/SensorFusion.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_SENSOR_FUSION_H
+#define ANDROID_SENSOR_FUSION_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <utils/SortedVector.h>
+#include <utils/Singleton.h>
+#include <utils/String8.h>
+
+#include <gui/Sensor.h>
+
+#include "Fusion.h"
+#include "SecondOrderLowPassFilter.h"
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+class SensorDevice;
+
+class SensorFusion : public Singleton<SensorFusion> {
+    friend class Singleton<SensorFusion>;
+
+    SensorDevice& mSensorDevice;
+    Sensor mAcc;
+    Sensor mMag;
+    Sensor mGyro;
+    Fusion mFusion;
+    bool mEnabled;
+    bool mHasGyro;
+    float mGyroRate;
+    nsecs_t mTargetDelayNs;
+    nsecs_t mGyroTime;
+    mat33_t mRotationMatrix;
+    SecondOrderLowPassFilter mLowPass;
+    BiquadFilter<vec3_t> mAccData;
+    vec3_t mFilteredMag;
+    vec3_t mFilteredAcc;
+    SortedVector<void*> mClients;
+
+    SensorFusion();
+
+public:
+    void process(const sensors_event_t& event);
+
+    bool isEnabled() const { return mEnabled; }
+    bool hasGyro() const { return mHasGyro; }
+    bool hasEstimate() const { return !mHasGyro || mFusion.hasEstimate(); }
+    mat33_t getRotationMatrix() const { return mRotationMatrix; }
+    vec3_t getGyroBias() const { return mFusion.getBias(); }
+    float getEstimatedRate() const { return mGyroRate; }
+
+    status_t activate(void* ident, bool enabled);
+    status_t setDelay(void* ident, int64_t ns);
+
+    float getPowerUsage() const;
+    int32_t getMinDelay() const;
+
+    void dump(String8& result, char* buffer, size_t SIZE);
+};
+
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_SENSOR_FUSION_H