TomTom Mazda NB1 Reference Manual page 27

Driving View goes grey.
GPS signal cannot be
received after starting the
car and the Mazda NB1.
GPS signal has been lost
temporarily.
When you first start your Mazda
NB1 navigation device, the
device may need a few minutes
to determine your GPS position
and show your current position
on the map.
27
Wait for the GPS signal to be
restored. If anything is obstructing
GPS reception, for example, a high
building, move away from it. Remove
any obstructions on the dashboard.
Wait until the device determines your
position. Using the QuickGPSFix
service can help your device to find
its position faster. To use
QuickGPSFix connect to LIVE
Services or to TomTom HOME.