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

1 files changed, 86 insertions, 0 deletions

diff --git a/services/sensorservice/CorrectedGyroSensor.cpp b/services/sensorservice/CorrectedGyroSensor.cpp
new file mode 100644
index 0000000..9b75b70
--- /dev/null
+++ b/services/sensorservice/CorrectedGyroSensor.cpp
@@ -0,0 +1,86 @@
+/*
+ * 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.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+
+#include <hardware/sensors.h>
+
+#include "CorrectedGyroSensor.h"
+#include "SensorDevice.h"
+#include "SensorFusion.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+CorrectedGyroSensor::CorrectedGyroSensor(sensor_t const* list, size_t count)
+    : mSensorDevice(SensorDevice::getInstance()),
+      mSensorFusion(SensorFusion::getInstance())
+{
+    for (size_t i=0 ; i<count ; i++) {
+        if (list[i].type == SENSOR_TYPE_GYROSCOPE) {
+            mGyro = Sensor(list + i);
+            break;
+        }
+    }
+}
+
+bool CorrectedGyroSensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event)
+{
+    if (event.type == SENSOR_TYPE_GYROSCOPE) {
+        const vec3_t bias(mSensorFusion.getGyroBias() * mSensorFusion.getEstimatedRate());
+        *outEvent = event;
+        outEvent->data[0] -= bias.x;
+        outEvent->data[1] -= bias.y;
+        outEvent->data[2] -= bias.z;
+        outEvent->sensor = '_cgy';
+        return true;
+    }
+    return false;
+}
+
+status_t CorrectedGyroSensor::activate(void* ident, bool enabled) {
+    mSensorDevice.activate(this, mGyro.getHandle(), enabled);
+    return mSensorFusion.activate(this, enabled);
+}
+
+status_t CorrectedGyroSensor::setDelay(void* ident, int handle, int64_t ns) {
+    mSensorDevice.setDelay(this, mGyro.getHandle(), ns);
+    return mSensorFusion.setDelay(this, ns);
+}
+
+Sensor CorrectedGyroSensor::getSensor() const {
+    sensor_t hwSensor;
+    hwSensor.name       = "Corrected Gyroscope Sensor";
+    hwSensor.vendor     = "Google Inc.";
+    hwSensor.version    = 1;
+    hwSensor.handle     = '_cgy';
+    hwSensor.type       = SENSOR_TYPE_GYROSCOPE;
+    hwSensor.maxRange   = mGyro.getMaxValue();
+    hwSensor.resolution = mGyro.getResolution();
+    hwSensor.power      = mSensorFusion.getPowerUsage();
+    hwSensor.minDelay   = mGyro.getMinDelay();
+    Sensor sensor(&hwSensor);
+    return sensor;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+