@rider I would bet some money that you have "high accuracy" checked in your location services? Am I right?
Edit: i am saying this because in my phone, if I enable hight accuracy using wifi, data, sygic arrow begins to jump from one place to the other, whereas if I use ONLY GPS, it doesnt and goes correctly.
In order to be able to set GPS ONLY...you need to erase some data in google location services. So when you click the first time on Location (gps) a pop up comes asking if you allow google to connect blabla...you click NO...and gps goes automatically into GPS ONLY.
Hope that will help if you have high accuracy mode.