Depending on the length of time the power was interrupted, your system may require GPS initialization.

If initialization is not necessary, the system proceeds directly to the Startup Confirmation screen.
If the system fails to locate a sufficient number of satellites to locate your position within 10 minutes, the following screen is displayed.

If you are experiencing GPS reception problems:
Controls
This chapter explains how to operate the various controls necessary for
driving. ...
Information
This chapter includes your vehicle’s specifications, locations of
identification numbers, and other
information required by regulation. ...
Navigation—Home Addresses and Going Home
The “Home” feature automatically routes you to your home address from any
location simply by selecting Go Home 1 or 2, or saying d “Go
Home.” You can store two home addresses as Home Addres ...