double-theodolite observation

double-theodolite observation

[¦dəb·əl thē′äd·əl‚īt äb·zər′vā·shən]
(engineering)
A technique for making winds-aloft observations in which two theodolites located at either end of a base line follow the ascent of a pilot balloon; synchronous measurements of the elevation and azimuth angles of the balloon, taken at periodic intervals, permit computation of the wind vector as a function of height.