filtering accelerometer data samples

hi, i am a newbee and i am facing problems with filtering noise from Accelerometer data. here is a few of data:

    X               Y             Z
-5.8094177  0.067977905  8.280548
-5.8594055  0.189376830  8.137726
-5.8391724  0.120346070  8.140106
-5.8189390  0.150100710  8.196045
-5.8463135  0.089401245  8.225800
-5.8832090  0.057266235  8.242462
-5.8522644  0.066787720  8.224609
-5.8808290  0.035842896  8.193665
-5.9022520  0.062026978  8.156769
-5.8927307  0.137008670  8.238892
-5.8260803  0.045364380  8.198425
-5.8689270  0.092971800  8.279358
-5.8677370  0.078689575  8.2127075
-5.8748780  0.097732544  8.244843

the sampling frequency here is 150HZ. how can i filter this data in matlab?

Answer 1

[Star Strider]

First, do a Fourier analysis of your signal. See the documentation on the fft function, paying particular attention to the code between the first two plot figures. The Fourier transformed data will give you a good idea of the frequencies of your signal and the frequencies of your noise.

Second, design a band-pass filter to pass only your frequencies of interest (or low-pass filter if you want to retain the d-c offsets such as gravity). There are several ways to design filters in MATLAB. My filter design procedure is here : How to design a lowpass filter for ocean wave data in Matlab? You will need the Signal Processing Toolbox.

Also, search on accelerometer in MATLAB Answers. You are not the first person to need to filter accelerometer data.