PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Air Traffic Control Fully Certified
Situational Awareness; Other / Unknown
ATC Issue All Types
Air Traffic Control Issued New Clearance
ATC Equipment / Nav Facility / Buildings
A PA28 was on a base turn heading 140 degrees; 5 miles behind (increasing) a faster C182. All of a sudden ISR showed on the RADAR (increased separation required) and the target started tracking right at the lead aircraft now showing a good altitude (3;400) and 190 KTS. Instant loss of separation; I turned the PA28 further away heading 120 because of where the RADAR showed him. All of a sudden the PA28 target jumped back to where it should have been; 1.5 miles east; heading through the final; towards higher terrain. I turned him back to the final. Separation was never really lost; even though the RADAR said it was; and the RADAR equipment completely erroneous target and tracking caused me to turn this aircraft into a more dangerous position. Fusion run without its closest sensor working is not reliable.
SCT Controller described a near loss of MVA required standards; the reporter claiming the 'Fusion' RADAR system provided erroneous information regarding separation; prompting a turn which caused the event.