drift meter

drift meter

[′drift ‚mēd·ər]
(navigation)
An instrument for measuring drift angle. Also known as drift indicator; drift sight.

drift indicator

drift indicator
Drigt-indicator.
An instrument that looks vertically at the surface to provide an indication of drift angle. It consists essentially of a sight tube with a hairline that is rotated until objects on the ground travel parallel to it. This direction is compared with the course to get the drift angle. Also called a drift meter or drift sight meter.