Mabe take a look at the documentation on page : http://doc.mokotechnology.com/index.php?s=/2&page_id=182there is a complete work out off a example off your GPS data.
First decode a payload by hand with pencil and paper so that you are sure you understanding how it is supposed to be done.
Then look at examples for other payloads and adapt them to yours.
tanks I have done decode the payload to a decimal value, so now how to convert this decimal value :
to the right latitude.longitude format?
The instructions show you how to convert that format in to degrees, minutes, seconds. See the part that says:
These would appear to but you in the Longhua district of Shenzhen?
On Github you can find the payload to convert in coördinates https://github.com/uknowwho/loragps.