My gps is not working as well as it worked - any advices?

Try a forced restart of your iP7: press and hold both the Side (Power) and Volume Down buttons for at least 10-15 seconds, until you see the Apple logo. When it appears, release both buttons, wait for your device to restart, then test it.

If you don't have anything (case or screen protector) that can obstruct your iP7's antenna, and the issue still persists, have your iphone checked at your most convenient Apple Store or Authorized Service Provider:

Apple - Find Locations - Location Selector

Regards

Giulio

Read this then repost your question: https://discussions.apple.com/docs/DOC-5931

Glad it worked. Have a nice day.