Continuous liquid level measurements with time domain reflectometry

A time domain reflectometer is considered as a closed loop, one-dimensional radar system. Applying the principle of time domain reflectometry to the detection of cryogenic liquid levels, measurements on the order of + or - 0. 3% of total liquid level probe length are possible. The time domain reflectometer liquid level measurement is independent of liquid density variations and is simple to calibrate and operate. Construction of the liquid level sensing probe is described.