Improvements in target ranging by HF radar using the European ionospheric model PRIME

Target ranging by HF radar can be done by correcting the group path of targ et echoes for the delay due to the propagation through the ionosphere. One possibility is to simulate the propagation by ray-tracing but in this case the final accuracy obtained in target registration depends mainly on the qu ality of the ionospheric model used to ray-trace. In this study, the PRIME ionospheric model has been used to perform ray-tracing on a 950 km path, be tween Toulon and Lannion, for which oblique soundings data from the SCIPION sounder are available for December 1991. The ray-tracings were performed b y using the vertical electron density profiles at five points along the pat h calculated by PRIME for monthly median and/or instantaneous conditions. V ertical electron density profiles from the IRI model have also been conside red for comparison. The results of this investigation are presented and the accuracy in target ranging is discussed as obtained for the conditions of the simulations. (C) 1999 Elsevier Science Ltd. All rights reserved.