I don't think that a mobile phone is a good way of doing that. You will need some serious programming skills to get a mobile phone to read a USB mouse.
It would be far simpler to use a microcontroller and a GPS receiver.
You can interface to the photodetectors directly with the microcontroller. You can use the USART on the microcontroller to read the NMEA strings from the GPS receiver, and to transmit the data to a PC, via the serial port.
In fact, as you only need to receive data from the GPS, and you only need to transmit data to the PC, you could probably use a low end microcontroller with just one USART.