Lap times can be measured by using GPS of the phone. The time gap to the best lap is displayed while measuring it. If the sector is set, each sector's gap is displayed. Past lap times can be confirmed from the history screen.

The measurement using an external GPS receiver by Bluetooth is possible.
To cmmunicate with external GPS receiver, external GPS receiver should be able to send NMEA0183 RMC sentence with SPP(Serial Port Profile).