I have built an application using the MPL3115A2 in Altimeter mode to track vertical travel. I'm seeing widely variable distances for the same trip; as much as 1.9 meters, with trips as short as 3.6 meters over about 4 seconds. This is really messing up my ability to tell where I am. The variation is much worse than I expected, given the accuracy of 0.3m listed in the datasheet.
Even looking at the altitude reading when I return to the same spot, I'm seeing way more variation than .3m. Is there a trick to getting this kind of accuracy? I've put the chip into altimeter mode, and set oversampling to maximum. I'm reading one sample per second (as expected). Any other suggestions for what to look at, or what I should be doing? In this case, I don't really care about the absolute altitude, but rather the difference after movement. The movement is seconds (between about 4 to as much as minute). Sometimes we'll sit in one place for many minutes; sometimes only a few seconds.
Should I be using a different sensor? Configuring this one a different way? Should I be massaging the data I get in some way? Any help would be greatly appreciated.