I have just received the dGPS that is made by Dexter Industries.
I have been playing over the last few days. I have been using it to collect information, that I later convert and upload directly to Google Maps
I will continue to modify the NXT-G codes, making it easier to use. Before uploading the finished NXT-G codes here.
I am also in the middle of editing a special Excel file that will auto generate the KML file used by Google Maps. Easier to manipulate the data for upload.
I will do a full review over the next few days, completing the NXT-G codes as well as any other files created.