Astronauts have shared the ISS with three small robots called SPHERES since 2006.
The robots are there to test whether menial tasks on the station can be automated, freeing up astronauts to do more interesting things.
At the moment, the bots are confined to a 2-metre-wide cube marked out by five ultrasound beacons, which transmit a locating signal that works like GPS does on Earth, 'New Scientist' reported.
If the SPHERES could travel around the whole station it would be much more useful, so Terry Fong at the NASA Ames Research Center in California and colleagues are trying to guide them using the ISS's existing Wi-Fi.
In an experiment, an astronaut floated around the US section of the station with a smartphone, measuring the varying signal intensity from two Wi-Fi routers at different points.
The team turned this data into a map capable of locating a SPHERE robot to within 1.59 metres, accurate enough to identify which ISS module it is in.