Controller described an asde alarm indicating 'runway occupied;' that resulted in a high speed abort...

Narrative:

Moderate precipitation was present over the field and asde was not in 'rain mode' during this event. I cleared air carrier X for take off runway xxl. Near taxiway wb; approximately 3;100 ft down the runway; amass alarmed with 'runway xxl occupied' and a primary return circled near taxiway wc. I canceled air carrier X's takeoff clearance and reported to him that it appeared something entered the runway down field. He turned off the runway shortly after that and reported hot brakes. It was determined that it was a false target after a thorough search through binoculars and by an airport operations vehicle. After that; there were numerous false targets on both runways xxl and xxr. Asde was placed in rain mode after the event and false targets persisted. Asde should have done a better job differentiating false targets; especially after [being] put into rain mode. I'm not sure what to recommend other than to say that if asde were better; this would not have happened.

Original NASA ASRS Text

Title: Controller described an ASDE alarm indicating 'runway occupied;' that resulted in a high speed abort. The reporter indicated a false target initiated the alarm.

Narrative: Moderate precipitation was present over the field and ASDE was not in 'rain mode' during this event. I cleared Air Carrier X for take off Runway XXL. Near Taxiway WB; approximately 3;100 FT down the runway; AMASS alarmed with 'Runway XXL occupied' and a primary return circled near Taxiway WC. I canceled Air Carrier X's takeoff clearance and reported to him that it appeared something entered the runway down field. He turned off the runway shortly after that and reported hot brakes. It was determined that it was a false target after a thorough search through binoculars and by an airport operations vehicle. After that; there were numerous false targets on both Runways XXL and XXR. ASDE was placed in rain mode after the event and false targets persisted. ASDE should have done a better job differentiating false targets; especially after [being] put into rain mode. I'm not sure what to recommend other than to say that if ASDE were better; this would not have happened.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	965901
Time
Date	201108
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Night
Aircraft 1
Make Model Name	A319
Operating Under FAR Part	Part 121
Flight Phase	Takeoff
Flight Plan	IFR
Person 1
Function	Local
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Ground Event / Encounter Other / Unknown

Controller described an asde alarm indicating 'runway occupied;' that resulted in a high speed abort. The reporter indicated a false target initiated the alarm.