I have a working Sygic with Tomtom Mk2 Bluetooth GPS receiver on a Galaxy.
Therefore i used a free app from Google playstore called Bluetooth GPS, the one with the lightblue icon.
Just only a few prefercences to make within the app before it works.
My internal GPS is off, bluetooth is on; first turn on my Tomtom MK2, then choose the Bluetooth app and select the connect button, after this comes Sygic to open and it will show position within 10 seconds.
Make sure you enable the Mock GPS provider setting in the bluetooth app and it wil work togetter well.
I must say this succeed after trying 8 different apps for the same purpose, to get my external gps signal working on Sygic navigation.