Sat Nav issue

Mazda 5 1.6 D 2013
Hi So i have a Mazda 5 2013 1.6D (UK)
the SAT NAV has never been great but now it simply doesn't work. The problem is it cannot seem to get an accurate fix on where the car is. Occasionally it will get it right. But 9 times out of 10 it will show the car in a location nowhere near where the car actually is. It seems to be a GPS problem so i wonder if i can replace the GPS receiver or is there a simpler fix? A secondary question would be should i just sack the old system and get a new one maybe with apple play, and would any of you have any recommendations for a replacement system?