GPS fenix 5

HI,
I think that would be killing the purpose of a GPS watch, isn't it? Plus if i rely on my Galaxy note 4 i think i snake would go more straight than its gps trace.

Is it posible to use an external GPS, ideally from the iphone? or some other GPS tracker?
I'm finding the GPS error is underestimating my distance, hence pace etc...

I don't think it's possible. I'm having the same problem when I run, even in clear open sky the gps track isn't even close to accurate.

You could try a Stryd footpod:

http://fellrnr.com/wiki/Stryd

I've always wondered this myself.
Sure the watch has inbuilt HRM, but you can use a HRM belt for better accuracy.

So why can't someone make a GPS antenna, like a wrist band that can connect via bluetooth (or other means) to the watch for better accuracy?

I'd be willing to by that!...