Medium Large Transport; Low Wing; 2 Turbojet Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 8
Situational Awareness; Human-Machine Interface; Confusion; Distraction
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance
ATC Equipment / Nav Facility / Buildings
Aircraft X departed Rwy 8R RNAV to HRSHL. IFR conditions once he got airborne; the radar showed him drifting south just like a lot of the previous departures. When the CA alert went off I asked him to confirm that he was in his left turn to HRSHL since I couldn't see him out of the window. The pilot replied that we are correcting. At that time I turned him to 040 heading and stopped his climb at 2500 feet. The aircraft off his right side was climbing out of 2700 feet. I was told closest proximity was .4 miles and less than 200 ft.About 10 minutes earlier the same situation occurred but the aircraft was actually on the right track the radar was wrong and the target jumped back to the right track. So when the radar showed Aircraft X drifting south I questioned the pilot instead of issuing an immediate turn; due to the fact that it has been known to show a target in one spot but the plane is actually in another spot. The radar has been doing this now for about 2 months and it has been a concern for controllers. 25 minutes or so later the radar showed an aircraft off runway 9L with a CA alert with himself while there was another departure of his left that also drifted south according to the radar. Our radar technicians have informed us that Gwinnett's sensor is out and this causes all of the anomalies. Fix Gwinnett's sensor or take us off Fusion.
ATL Tower Controller reported of target jumps due to the Fusion RADAR which contributed to a loss of separation.