Sat ground controller reported that an aircraft taxied across an active runway during low visibility...

Attributes
ACN	1505104
Time
Date	201712
Local Time Of Day	1201-1800
Place
Locale Reference	SAT.Airport
State Reference	TX
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Make Model Name	Commercial Fixed Wing
Flight Phase	Taxi
Route In Use	None
Aircraft 2
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 135
Flight Phase	Landing
Flight Plan	IFR
Person 1
Function	Ground Trainee
Qualification	Air Traffic Control Developmental
Events
Anomaly	ATC Issue All Types Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Ground Incursion Runway

Narrative:

Aircraft X was holding short of november on romeo. Runway 4 [was under ground control] for taxiing and not being used for departures. I gave instructions for aircraft X to turn right on runway 4 and hold short of runway 13R. The pilot's first read back was unconvincing so I restated instructions. The second read back was acceptable. I asked pilot to advise when holding short of runway 13R due [to] visibility being very low. Shortly after aircraft X advises holding short of runway 13R. I acknowledged with 'roger.' I gave taxi instructions to aircraft Y; which just exited runway 13R. Immediately after aircraft Y read back; aircraft X advises he is at runway 4 at N3. I said 'say again'. Aircraft X again advised on runway 4 at N3 which is on other side of runway 13R. I issued the brasher warning and the pilot called in.[I recommend] installing asd-X at san antonio airport.

Original NASA ASRS Text

Title: SAT Ground Controller reported that an aircraft taxied across an active runway during low visibility conditions.

Narrative: Aircraft X was holding short of November on Romeo. Runway 4 [was under Ground Control] for taxiing and not being used for departures. I gave instructions for Aircraft X to turn right on Runway 4 and hold short of Runway 13R. The pilot's first read back was unconvincing so I restated instructions. The second read back was acceptable. I asked pilot to advise when holding short of Runway 13R due [to] visibility being very low. Shortly after Aircraft X advises holding short of Runway 13R. I acknowledged with 'Roger.' I gave taxi instructions to Aircraft Y; which just exited Runway 13R. Immediately after Aircraft Y read back; Aircraft X advises he is at Runway 4 at N3. I said 'Say Again'. Aircraft X again advised on Runway 4 at N3 which is on other side of Runway 13R. I issued the Brasher warning and the pilot called in.[I recommend] installing ASD-X at San Antonio airport.

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.

Sat ground controller reported that an aircraft taxied across an active runway during low visibility conditions.