Removing drift/offset and noise from accelerometer data

Hi all,

I am using the sensors within my phone to generate a CSV file of accelerations in 3-axis (x,y,z). I have now imported the data to matlab using the CSVread funtion and have began processing the data.

I have applied a filter to reduce some of the noise from the signal however upon integration the signal still drifts. The code I am using is shown below, for simplicitys sake I am only showing data from one axis. Any help is appreciated

clear; close; clc;
D=csvread('test20m3.csv');
t=D(:,1);                                                                           %Define time
XAccRaw=D(:,5);                                                                     %Define X acceleration
XAcc=XAccRaw*9.81;                                                                  %Convert to m/s^2
d=designfilt('lowpassfir','filterorder',10,'CutOffFrequency',10,'SampleRate',100);  %Lowpass FIR filter
AX=filtfilt(d,XAcc);                                                                %Apply filter to data
VX=cumtrapz(t,AX);                                                                  %Integrate acceleration to get velocity
SX=cumtrapz(t,VX);                                                                  %Integrate velocity to get displacement
figure(1);
plot(t,SX);
xlabel(Time (s));
ylabel(Displacement (m))