Hey guys and girls ^~^
I hope this question is ok as it's not entirely dev related.

I'm planning on building a custom cattracking device that i can attach to a cat harness. It obviously has to be very small and light. This is why i had the pi zero in mind.
I want to track my cat via Gps and send location via gsm (and use a trigger if he connects to my wifi to set off an alarm so i can let him in).
My experience with pi's is limited but i have some with arduinos.
Besides that i would need a case which keeps the pi save from dust, humidity and maybe rain but won't interfere too much with the gsm signal.
First: is this even possible?
If yes, what would you recommend?
Are there better ways to do this?

Thanks to all in advance