How to obtain autocorrelation function of long spanned GPS time series with lags of one month, six month and one year

How to obtain autocorrelation function of long spanned GPS time series with lags of one month, six month and one year, Please help me

[Wayne King]

What is the sampling interval for the measurements?

[Chris Martin]

interval 0.00274 is equivalent to 1/365 i.e the unit of the second column is in per year.

365 days = 1 year 1 day=1/365 year

[Chris Martin]

Please help me......

[Walter Roberson]

Which toolboxes do you have available? I see autocorrelation functions available in at least DSP and Econ.

Answer 1

[Walter Roberson]

http://www.mathworks.com/matlabcentral/fileexchange/30540-autocorrelation-function-acf

To determine the appropriate lag, you are going to need to specify how you want to deal with the irregular number of days in a month and the fact that the two 6 month periods are of different length (have to be, as there is an odd number of days in a year.)