I just came across this word: Consilience
In science and history, consilience (also convergence of evidence or concordance of evidence ) is the principle that evidence from independent, unrelated sources can “converge” on strong conclusions. That is, when multiple sources of evidence are in agreement, the conclusion can be very strong even when none of the individual sources of evidence is significantly so on its own.
When we think in terms of standard navigation practices we think in terms of the "cross-check. That is to use another standard but independent method, for example visual bearings and radar ranges. These sources are “related”.
But if the search for information is broadened, looking for “convergence of evidence”, then information might be available from meteorology: If the GPS Fails I’m Riding the Isobars Home or the things learned from the fisherman: We don’t need no stinking compass
These sources are unrelated, less obvious.