Is that possible to use a GSM GPRS Shield (SIM900)
Yes, of course.
with an SMA antenna?
That is something that only you can answer. Is there one available for your shield? If so, will it with with your enclosure? If so, will it have the range that you need?
See, if you ask questions we can answer, we will. Asking compound questions makes them more difficult to answer.
Is there someone ho get the coordinate using the GSM relay.
That will depend, too, on which GSM chip/shield you select. There are no generic answers when it comes to these chips/shields.