Natapat,
My previous post would apply to those in the USA as the links I provided are only for the US. This is the link to the VRS post. TB_RTK did a video on how to do this but I have not yet comprehended the whole process. Since you are in Asia, with no correction bases close by, then if you can learn how to create and use VRS then it would be really nice. He already showed you sample of what he got using VRS. Very nice!!