i am using sketchup 2015 pro now. and i want to use geolocation but it said that is not available in the version that i use. so i download sketchup 2018 pro but it is only support 64bit system. so are there any method that i can use geolocation in sketchup 2015 instead of update my version?
No. See: Upcoming Change to Add Location
For correct shadows, you can still manually add the geolocation, though.