LATERAL DEVIATION OF OBLIQUELY PROPAGATED HF RADIO RAYS

As is well known, magnetoionic splitting of obliquely propagated HF radio waves may result in deviation of such waves from the great-circle plane between transmitter and receiver. A computer raytracing routine has been employed at Stanford to investigate the properties and maximum extent of this phenomenon under realistic ionospheric conditions. It is concluded that for a 1000 km path the difference in azimuthal bearing between the ordinary and extraordinary modes could reach a maximum of 0.5 deg, corresponding to an 0.25 deg variation of either mode from the true bearing. However, in most practical bearing estimation problems, the difference is an order of magnitude smaller than this maximum, and thus is truly small in comparison with other sources of error.