B747-400 ILS MALFUNCTIONED; RESULTING IN TWO CONSECUTIVE GAR'S. FLT DIVERTED TO VFR ALTERNATE.

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CLRED FOR ILS IN ZZZ. LOW FOG AT END OF RWY. RVR 2800-1800 FT THEN 5000 FT BACK TO 2000 FT. WE WERE VECTORED FOR THE ILS; FO WAS FLYING. INTERCEPTED THE ILS WITH AUTOPLT ON. ACFT INTERCEPTED THE GS. AT ABOUT 1200 FT WE NOTICED THE FMC MAP WAS L OF OUR COURSE. GS AND LOC WERE CTRED WITH NORMAL INDICATIONS. WE FELT THAT THERE MUST HAVE BEEN A MAP SHIFT. ALL ILS DATA INDICATIONS WERE NORMAL; CORRECT FREQS WERE TUNED. WE CONTINUED THE DSCNT TO MINIMUMS. DID NOT SEE RWY ENVIRONMENT. I TOLD FO TO GO AROUND. HE INITIATED A NORMAL GAR AND WE CLBED TO 5000 FT. WE THEN HEADED DOWNWIND AND SAW THAT WE HAD AROUND 19.5 LBS OF FUEL. WE DECLARED MINIMUM FUEL TO GET EXPEDITED HANDLING FOR ANOTHER APCH. WE AGREED THAT WE WOULD TRY ONE MORE APCH AND THEN GO TO ZZZ1. WE AGREED THAT WE WOULD DO A CAT III AUTOLAND ON OUR NEXT APCH. I TOOK OVER AS PF; FO SET UP FOR THE CAT III AUTOLAND. WE COMPLETED THE APCH DSCNT CHKLIST. WE ALLOWED THE AUTOPLT TO INTERCEPT THE ILS AGAIN; ONCE ESTABLISHED ON THE APCH WE COUPLED ALL 3 AUTOPLTS FOR AUTOLAND. WE NOTICED THAT WE WERE R OF THE FMC MAP AGAIN. LOC AND GS WERE NORMAL AND CTRED. AT ABOUT 1800 FT THE TWR CALLED AND SAID THAT WE LOOKED R OF COURSE; WE AGREED. CONTINUED TO AROUND 1500 FT AND STARTED ANOTHER GAR. CLBED TO 5000 FT; DURING CLB THE FUEL INDICATED AROUND 16000 LBS. WE DECLARED A LOW FUEL EMER AND REQUESTED LNDG AT ZZZ1. I FLEW THE AIRPLANE AND BOTH FO'S SET UP FOR THE ILS APCH. WX AT ZZZ1 WAS CLR; THERE WAS A FOG BANK RIGHT AT THE ARR END OF THE RWY. FO'S SET UP FOR THE ILS IN ZZZ1. I FLEW A VISUAL DOWNWIND AND BASE FOR THE RWY. WE TURNED FINAL I USED THE VASI AND FLEW VISUALLY TO THE RWY. AGAIN THE ILS GAVE THE WRONG INDICATIONS. IT WAS CALLING FOR US TO COME R OF COURSE. WE LANDED VISUALLY AND PARKED WITHOUT INCIDENT AT THE GATE. WE SPOKE WITH FLT OPS; MAINT; AND DISPATCH. CUSTOMS WAS NOT AVAILABLE AND IT WOULD TAKE BTWN 5-6 HRS TO GET THEM THERE. WE ALL AGREED THAT WE WOULD WAIT FOR THE SUN TO GO DOWN TO DEPART ZZZ1. WE PLANNED TO HAVE ENOUGH FUEL ONBOARD TO FLY AROUND FOR A WHILE AND WAIT FOR THE FOG TO LIFT OR GO TO ZZZ2 OR ZZZ3; IF NEEDED; AS THEY BOTH HAVE CUSTOMS. FO WAS IN CONTACT WITH ZZZ AND ZZZ1 TWR WATCHING THE WX SETTING A TIME FOR US TO DEPART. ONCE WE REFUELED AND ALL PAPERWORK WAS COMPLETED WE DEPARTED FOR ZZZ. WX WAS CLR AND 12 MI. WE DID A VISUAL APCH AND HAD A NORMAL LNDG IN ZZZ. WE DID TUNE THE ILS. IT WAS SHOWING THAT WE WERE 2 DOTS L OF THE ILS COURSE. WE WERE LINED UP WITH THE RWY AND ON THE FMC CTRLINE. ON LNDG THE AUTOBRAKES #2 WERE VERY ROUGH AND OSCILLATED IN AND OUT FROM 130 KTS TO ABOUT 100 KTS WHEN I TURNED OFF THE AUTOBRAKES. WE ARRIVED AT ZZZ APPROX 2.45 HRS LATE. ALL FLT OPS WERE PERFORMED PER SOP.