Regional Jet 700 ER/LR (CRJ700)
Flight Crew Air Transport Pilot (ATP)
Other / Unknown
ATC Issue All Types
Air Traffic Control Issued New Clearance
ATC Equipment / Nav Facility / Buildings
On the ILS PRM 9R; approximately at BURNY; Final Monitor called stating something to the effect of '[Air Carrier X]; I show you right of course; return to the LOC immediately.'  We were coupled to the AP. I looked up and confirmed on both left and right LOC that we were dead center on the LOC. Also; we had the runway in sight at this point and visually; we were right on centerline with 9R. The First Officer replied stating that we indicated we were on the LOC center. The Monitor then replied something to the effect of 'I had a RADAR error; my apologies; continue.' We then continued without issue.  Cause; this is something that I haven't seen or heard of before. Fortunately; we were VMC to where we could confirm our location. Because we could see both the runway and traffic to our left and right on parallel approaches; we did not make a left turn. I'm not sure what caused this brief confusion; but I thought it would be worth noting in a report.
Air Carrier on ILS PRM 9R to ATL was questioned by ATC as to LOC tracking; the flight crew confirmed both via instruments and visually 'on course'; Controller acknowledged ATC equipment faults.