FLC TECHNIQUE NAV INADEQUATE. HDG TRACK POS DEV IN A GROSS NAV ERROR.

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CANADIAN ATC ASKED OUR POS PASSING 110W (AFTER RE- ESTABLISHING RADIO CONTACT THROUGH ACARS). THEY RPTED WE CROSSED AT 56N AND 110W INSTEAD OF 56.30N 110W. THE WAYPOINT WAS CHKED NUMEROUS TIMES BY BOTH PLTS ACCORDING TO COMPANY STANDARDS. IN DOING SO; AS WE CROSSED OUR PREVIOUS WAYPOINT WE CHKED 56N 110W ON OUR FMC'S INDEPENDENTLY. THE FLT PLAN 'POINT' WAS CALLED 56N 110W BUT THE REAL POS WAS 56.30N 110W. LOOKING DOWN INTO THE SCRATCH PAD WE THOUGHT WE SAW THE CORRECT POS AND THE MILEAGE CHKED GOOD. THE 'LEGS' PAGE SHOWS THE POS AS 56N 110W. WHEN BROUGHT DOWN INTO THE SCRATCH PAD IT WOULD SHOW AS 5630.0N 110.000W. APPARENTLY THE ERROR WAS NOT CAUGHT AND 56.000N 110.000W WAS LOADED INTO THE CDU. WE WERE RPTED OFF COURSE AND A NAV ERROR RPT WOULD BE FILED. THE WRONG WAYPOINT WAS LOADED ON THE GND BUT NOT CAUGHT IN THE SOPA CHK (TIME AND DISTANCE WERE GOOD) BY BOTH PLTS. RADIO'S WERE INTERMITTENT ENRTE AND WERE ADVISED TOO LATE OF OUR DRIFTING OFF COURSE. AFTER RADIO CONTACT; WE WERE TOO LATE TO CORRECT WITHIN TOLERANCES. CANADIAN ATC ADVISED US OF OUR SIT AND WE CORRECTED TO COURSE. DURING OUR 'CHKS' OUR EYES SAW WHAT OUR MINDS WANTED US TO SEE ESPECIALLY SINCE THE TIME AND MILEAGE WERE CORRECT OR APPEARED CORRECT. THE RANDOM RTE SYS OVER NORTHERN CANADA IS NEW AND THE ATC SYS SHOULD BE MORE PROACTIVE WHEN AN ACFT IN RADAR CONTACT SEEMS TO BE DIVERTING OFF COURSE. WE WERE ADVISED AFTER THE WAYPOINT; 30 MI OFF COURSE OR 30 MINS. SURELY THEY COULD HAVE HELPED US EARLIER.