Sat tower controller reported a runway incursion.

Attributes
ACN	1520180
Time
Date	201802
Local Time Of Day	1201-1800
Place
Locale Reference	SAT.Airport
State Reference	TX
Environment
Light	Dusk
Aircraft 1
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	Taxi
Person 1
Function	Local
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 3
Events
Anomaly	Deviation - Procedural Clearance Ground Incursion Runway

Narrative:

I had an aircraft one mile final for runway 13L and as I was scanning the surface area I noticed aircraft X crossing runway 13L at taxiway north. I instructed ground of the deviation and ground control (ground control) immediately prompted aircraft X to clear the runway.there is a big communication barrier with foreign pilots and the placement of our customs ramp and fbos requiring numerous runway crossings. Some sort of ground radar may not prevent the incursions from happening but it may be the difference in catching one of these where we might otherwise not.

Original NASA ASRS Text

Title: SAT Tower Controller reported a runway incursion.

Narrative: I had an aircraft one mile final for Runway 13L and as I was scanning the surface area I noticed Aircraft X crossing Runway 13L at taxiway N. I instructed ground of the deviation and GC (Ground Control) immediately prompted Aircraft X to clear the runway.There is a big communication barrier with foreign pilots and the placement of our customs ramp and FBOs requiring numerous runway crossings. Some sort of ground radar may not prevent the incursions from happening but it may be the difference in catching one of these where we might otherwise not.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.