This unit is from UK wartime aircraft, and computed an aircraft's latitude and longitude using an entirely mechanical (analogue) process, involving integration, sines and cosines.
The current speed and direction were fed in on servo-motors on the right of this photograph.
The speed was split mechanically into sine and cosine components for latitude and longitude changes, and integrated to give the current position.
The longitude calculation also needed an inverse "cosine" component (longitude changes more quickly nearer the poles proportional to the cosine of the latitude). The mechanical process would, of course, have failed near the north or south poles.

From Richard Powell: The speed of the aircraft was by a mechanical drive, like a speedo cable, at 24 Revs/mile from the Air mileage unit. This compared Static and Pitot pressure. The attachment can be seen lower slightlly right of cenrtre.  On the top right of the picture is the "M" drive motor, its input from the Distant reading Compass, via the Variation Setting Control.  The rotating switches on the right are "M" drives, a stepper type output, N-S  and E-W that feed the Ground position Indicator and Wind finding attachment.  I have a working setup of this Automatic dead reckoning system for demonstrations. See figure 1.