A position-determining device comprising: a processor; a memory; a global positioning system, GPS, receiver to enable receiving of signal data from a plurality of satellites; and a plurality of modules (110, 122, 124) stored in the memory, wherein the plurality of modules (110, 122, 124) include a phone module corresponding to a phone mode to provide mobile phone functionality and a position-determining module corresponding to a navigation mode to provide position-determining functionality and configured to utilize the signal data received via the GPS receiver to output navigation instructions, and wherein said plurality of modules (110, 122, 124) are executable on the processor to: monitor connection of the position-determining device to a corresponding mounting device; characterized in that said plurality of modules (110, 122, 124) are further executable on the processor to: when the position-determining device is monitored to be disconnected from the corresponding mounting device, automatically select the phone mode to provide the mobile phone functionality as active operational mode for the position-determining device; and when the position-determining device is monitored to be connected to the corresponding mounting device, automatically select the navigation mode configured to utilize the signal data received via the GPS receiver to output navigation instructions as active operational mode for the position-determining device. a processor; a memory; a global positioning system, GPS, receiver to enable receiving of signal data from a plurality of satellites; and a plurality of modules (110, 122, 124) stored in the memory, wherein the plurality of modules (110, 122, 124) include a phone module corresponding to a phone mode to provide mobile phone functionality and a position-determining module corresponding to a navigation mode to provide position-determining functionality and configured to utilize the signal data received via the GPS receiver to output navigation instructions, and wherein said plurality of modules (110, 122, 124) are executable on the processor to: monitor connection of the position-determining device to a corresponding mounting device; characterized in that said plurality of modules (110, 122, 124) are further executable on the processor to: when the position-determining device is monitored to be disconnected from the corresponding mounting device, automatically select the phone mode to provide the mobile phone functionality as active operational mode for the position-determining device; and when the position-determining device is monitored to be connected to the corresponding mounting device, automatically select the navigation mode configured to utilize the signal data received via the GPS receiver to output navigation instructions as active operational mode for the position-determining device. when the position-determining device is monitored to be disconnected from the corresponding mounting device, automatically select the phone mode to provide the mobile phone functionality as active operational mode for the position-determining device; and when the position-determining device is monitored to be connected to the corresponding mounting device, automatically select the navigation mode configured to utilize the signal data received via the GPS receiver to output navigation instructions as active operational mode for the position-determining device.