GPS hardware defect repair?

Good afternoon everyone!

I have an iPhone 4, iOS 7.1.2. For some time now (one year at least) the GPS locating does not work anymore, accuracy in all apps only about 1.5km (= AGPS ...)

Wi-Fi and all other features are still working.

The following so far hasn't done any changes to this behavior:

- Restore my iPhone,

- Erase Content and Settings + Set up as new iPhone,

- pull out SIM card slightly -> then it says "Cannot determine Location", even after 2 h waiting period with open view to the sky.

So I'm 99% sure that it is a "hardware malfunction", and it's NOT the Wi-Fi / GPS antenna which is defective, but the problem goes even deeper, otherwise Wi-Fi probably would still be working, wouldn't it?

My question is: (google hasn't helped so far) Can I exchange the GPS receiver independently? I'd rather repair my phone by myself because I hate to give my device to someone else to have it repaired expensively.

I'll gladly let myself be disabused, if anyone thinks it's not a hardware defect.

So: Is there is a "pure" GPS receiver in the iPhone 4, which can be exchanged?

Thanks for any answers! (and sorry for bad english, i'm not a native speaker)