A method to test HF ray tracing algorithm in the ionosphere by means of the virtual time delay

As well known a 3D ray tracing algorithm furnishes the ray´s coordinates, the three components of the wave vector and the group time delay of the wave along the path. This last quantity can be compared with the measured group delay to check the performance of the algorithm. Simulating a perfect reflector at an altitude equal to the virtual height of reflection the virtual delay is assumed as a real group delay. For a monotonic electronic density profile we find a very small relative difference between the calculated and the simulated delay both for analytic and discrete 3D electronic density models.