GPS mouse? Unless you mean module (DYAC), can you please give a pointer?
http://www.royaltek.com/index.php/rgm-3600
There are dozens of variants, some with USB, some with RS232, some with bluetooth. "Mouse" is common nomenclature for this kind of device, I don't know why.
Basically, they all deliver continuous NMEA data over a serial line.
The term "GPS mouse" refers to the shape and size of the device, and has come to mean any wired or wireless GPS receiver that doesn’t come with any sort of interface. It merely outputs position data to a laptop, cell phone, etc.