(material design) Notification icon in appbar

[olddesign]

Hallo I am prototyping an app and was wondering if it is confirm to the material design guidelines to locate a notification icon in the appbar Like in runtastic it is essential for my app to switch on gps and have a signal.
But i do not know where to put the feedback. Of course if gps is on, it is in the statusbar but you should recognize it if it is off or without signal.

My appbar contains only sidedrawer an appname.

Thanks a lot!

 

[arnavrp]

app bar

App bar should be used to display actions.
There may be certain actions in your app which are available when GPS is on right, you should show those actions on app bar.

When GPS is not on, you show different set of actions.

That itself is an indicator to user to know whether GPS is on or not.