DGNSS 1 now agrees with Fanbeam within normal tolerance, and stays in agreement for ten continuous minutes. DGNSS 2 still shows an occasional small discrepancy. What is the appropriate next step?

A. Re-include DGNSS 1 into the position solution now that cross-technology agreement is confirmed and sustained, but keep DGNSS 2 excluded and under continued observation until it also demonstrates sustained agreement — a partial, evidence-based recovery, not an all-or-nothing decision

B. Wait for a fixed 24-hour period before re-including any GNSS reference, regardless of demonstrated stability

C. Re-include both DGNSS units simultaneously since DGNSS 1 has recovered

D. Exclude DGNSS 1 again since DGNSS 2 has not yet recovered

A. A Fanbeam fault, since it is the system not showing the change

B. A GNSS-wide problem affecting both satellite receivers simultaneously (interference, spoofing, or a satellite constellation issue) rather than two independent sensor faults — the fact that both units moved identically and together is the key clue, since genuinely independent reference systems failing identically at the same instant is far less likely than a shared external cause

C. Two simultaneous but entirely unrelated hardware faults in both DGNSS receivers

D. Normal GNSS behaviour requiring no further attention since both units still agree with each other

A. Trust the DGNSS units since there are two of them and only one Fanbeam, following a simple majority-vote assumption

B. Average the DGNSS and Fanbeam readings together to obtain a compromise position

C. Manually exclude both DGNSS units from the DP position solution immediately, relying on the Fanbeam (and any other unaffected reference) — do not wait for the DP system's automatic voting to resolve this, since two affected units may outvote the one correct reference if left to automatic logic

D. Take no action since the vessel's thrusters have not yet responded to the apparent jump