A DME Based on Standing Wave Conditions

A DME concept is described based on the measurement of conditions associated with the standing waves permitted by an instantaneous range. It is shown that for a given power the instrument will operate at greater ranges with higher space resolution than is possible by direct transit time measurements. The role of oscillator stability in limiting the range of interferometers is investigated, and it is concluded that a standing wave DME can tolerate an oscillator instability bandwidth as great as c/2R.