Grid Navigation

Grid navigation is a navigation system that uses a grid aligned to the Greenwich Meridian (True North) rather than magnetic north, replacing the normal compass directions with grid directions. It is used in polar regions where magnetic compasses are unreliable due to proximity to the magnetic north pole.

Why Grid Navigation?

In the Northern Domestic Airspace above approximately 70°N, the magnetic north pole is close enough that magnetic variation changes rapidly over short distances, magnetic compass reliability decreases significantly, and the angular difference between true north and magnetic north can be extreme (90° or more near the pole). Grid navigation uses a fixed reference — the Greenwich Meridian — to create a stable directional system.

Grid Navigation on Charts

Polar charts use the grid overlay. Converging meridians appear as parallel lines on the grid chart. The navigator flies grid headings rather than magnetic headings, with the grid north reference kept consistent throughout the polar transit.

Related Terms

See also: Arctic Control Area, Northern Domestic Airspace, Variation.