Progress towards a propagation prediction service for HF communications with aircraft on trans-polar routes

• Main Authors: Warrington, Michael, Rogers, Neil Christopher, Stocker, A. J., Hallam, Jonathan, Siddle, D., Al-Behadili, H.A.H., Zaalov, Nikolay, Honary, Farideh, Boteler, D., Danskin, Donald W.
• Format: Text
• Language: English
• Published: 2016
• Subjects: Leicester; Pacific; North Atlantic
• Online Access: https://eprints.lancs.ac.uk/id/eprint/81152/; https://eprints.lancs.ac.uk/id/eprint/81152/1/Warrington_et_al._2016_Nordic_HF_Paper_2016.pdf

Commercial airlines began operations over polar routes in 1999 with a small number of proving flights. By 2014 the number had increased to in excess of 12,000 flights per year, and further increases are expected. For safe operations, the aircraft have to be able to communicate with air traffic control centres at all times. This is achieved by VHF links whilst within range of the widespread network of ground stations, and is by HF radio in remote areas such as the Polar regions, the North Atlantic and Pacific where VHF ground infrastructure does not exist. Furthermore, the Russian side of the pole only has HF capability. Researchers at the University of Leicester and at Lancaster University have developed various models (outlined below) that can be employed in HF radio propagation predictions. It is anticipated that these models will form the basis of an HF forecasting and nowcasting service for the airline industry. Propagation coverage predictions make use of numerical ray tracing to estimate the ray paths through a model ionosphere. Initially, a background ionospheric model is produced, which is then perturbed to include the various ionospheric features prevalent at high latitudes (in particular patches, arcs, auroral zone irregularities and the mid-latitude trough) that significantly affect the propagation of the radio signals. The approach that we are currently adopting is to start with the IRI and to perturb this based on measurements made near to the time and area of interest to form the basis of the background ionospheric model. This is then further perturbed to include features such as the convecting patches, the parameters of which may also be informed by measurements. A significant problem is the high variability of the high latitude ionosphere, and the relative scarcity of real-time measurements over the region. Real time measurements that we will use as the basis for perturbing the IRI include ionosonde soundings from, e.g. the GIRO database, and TEC measurements from the IGS network. Real-time ...