Lateral bending effects at the ionospheric height transition

The paper investigates VLF propagation aspects relevant to an anomalous position error which is systematic in nature and tends to recur on successive dates at the same time and position with extensive use of the Omega long range radio location system on commercial air routes. Key co-terminator geometric relations useful for extraction of ionosphere height data from phase recordings over known paths are pointed out. A step model is used to confirm the applicability of geometric optics to the prediction of phase errors due to very long wave propagation through the terminator, and to account for serious errors due to lateral bending in VLF radio location systems.