How to convert the AIS data (ship gps data) to mobility traces for N S 2 movement model?

I want to evaluate routing protocols for ad hoc networks i NS2 software.

how to i convert ship GPS data (latitude, longitude, speed, time) ie AIS data into movement model for NS 2 mobility scenario.

i tried to use BONNMOTION with GPXimport but i failed to know the exactly procedure.

some papers discussed about it only without details.

thanks in advance!