Accuracy of android “linear acceleration” versus manual processing of accelerometer?

I did a little test- hold the phone as level as possible and walk in square pattern.

I did a little test- hold the phone as level as possible and walk in square pattern.

The raw Y-acceleration is getting the peaks about as well as linear acceleration, must be nothing special in the Droid 3 at least. How one could manually compute the gravity-debiased version: use recursive least-squares or something to solve for a vector of norm 9.8m/s^2 , assume that time-adjacent points are changing slower than some threshold.

Ali: sensor fusion mostly relates to the "orientation" data, but in practice the compass is a) slower , b) noisier c) less accurate than accelerometer, especially in metal environments. My question was whether anyone has tried a device where there's a big gain with the API's "linear acceleration" versus a manual attempt at estimating the gravity vector?

You are supposed to edit your own question insted of writing an answer. – Ali Aug 28 at 22:07.

It is not filtering but fusing the sensors data. Lots of maths and efforts went into the sensor fusion. There is no dedicated chip to remove gravity from the acceleration.

I highly recoomend the Sensor Fusion on Android Devices: A Revolution in Motion Processing video. UPDATE: I did not say a word about the compass. Sensor fusion relies heavily on the gyroscopes which have excellent transient response.

I do advise you to watch the above video. No offense but it is clear from your posts that you are not familiar with the very basics of sensor fusion.

As far as I can tell, only Nexus S and maybe some new tablets have gyroscopes, stackoverflow. Com/questions/4347143/… – peter karasev Aug 29 at 16:35 1 No offense but as soon as you say "no offense," it's clear you're about to give offense. Smile and be happy!

:) – Dave Swersky Aug 29 at 18:32 @peter karasev Yes, I have implemented sensor fusion on the Shimmer platform. These are motion sensors with gyros, not phones or tablets. Without the gyro data you can only do messy things and do not expect anything accurate.

By the way, what would you like to do with the linear acceleration? – Ali Aug 29 at 19:45 Just wondering if there was a point to using SDK level 9 at the expense of not supporting phones from 1 year ago. Inertial navigation or control-proportional-to-gravity-orientation that ignores gestures to drive a bot or play a game would be cool.

Sounds the answer is "no", not enough hardware support at the moment. Don't care about exotic platforms in this case, android is for $$ not intellectual enlightenment. – peter karasev Aug 290 at 17:40.

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