Hello, I am trying to develop an indoor inertial navigation system on the HTC hero with the built-in accelerometer and digital compass.
As far as I know about hardware, the accelerometer chip is the Bosch Sensortec's 3-axis BMA150 and the digital compass is Asahi Kasei's AK8973 (similar to iPhone). I am not sure about the accuracy of each sensor but the digital compass seems to function fairly well in the iPhone. What I am doing is getting accelerometer samples and magnetic field samples at the SENSOR_DELAY_FASTEST (seems to me around 10 - 20 ms per sample) Then I creates a threshold of ±1 m/s^2 for every output of accelerometer to filter out which sample is gravity (9.807f). The same is applied for output from the digital compass (with threshold of ± 5 microtesla). I intended to use this filter to provide the correct gravity and geomagnetic field for the SensorManager.getRotationMatrix to work correctly (I am not sure if this method would actual provide better result). >From the rotation matrix created above, I simply use getOrientation to get the heading (north) and convert the output from the accelerometer from the device coordination system to the Earth's coordination system by multiplying to the rotation matrix. ****** My question ****** The result I am getting is completely not usable. It seems that the heading is very inaccurate thus making the rotation matrix inaccurate. Even when I applied kalman filter, the result is still far from being usable. I wonder if anyone has approached this problem before and if there is some better way to do it. Thanks, lvmh --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~----------~----~----~----~------~----~------~--~---
