An Efficient Propagation Simulator for High Frequency Signals And Results from HF radar experiment Kin Shing Bobby Yau Supervisors: Dr. Chris Coleman & Dr. Bruce Davis School of Electrical and Electronic Engineering The University of Adelaide, Australia

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 2 Overview HF Ionospheric Propagation Simulator Simulation results Comparisons with Experimental Results Discussions Conclusions

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 3 Introduction HF radio system is still prevalent Military Over-the-Horizon RADAR HF communications Commercial broadcasting

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 4 Ionospheric Propagation Simulator A need for wideband HF propagation simulator Focussing on the fading effects of HF signals Employ theoretical model of fading  Efficient algorithm based on analytical expressions Two components of fading model:  Polarization Fading Model  Amplitude Fading Model

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 5 Polarization Fading Model Faraday rotation due to O and X wave interference

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 6 Polarization Fading Model Perturbation techniques to ascertain the change in phase path due to irregularities Use of frequency offset method to take into account of the magnetic field

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 7 Amplitude Fading Model Focussing and defocussing of radio waves due to movement of large scale ionospheric structure

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 8 Amplitude Fading Model Parabolic approximation to Maxwell ’ s equation (Wagen and Yeh): U is the complex amplitude,  is the refractive index with irregularities g and t are the local longitudinal and transverse coordinates

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 9 Amplitude Fading Model

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 10 Simulator Implementation Numerical ray tracing is used for the path quantities Accurate ray homing for finding all possible paths (Strangeways, 2000) Fading is calculated by the fading models

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 11 Simulation Results Alice Springs to Darwin

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 12 Simulation Results 10.6MHz -  = 0.05, L = 350km, v = 200m/s

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 13 Simulation Results 10.6MHz -  = 0.05, L = 350km, v = 200m/s

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 14 Simulation Results 10.6MHz -  = 0.05, L = 350km, v = 200m/s

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 15 Simulation Results 10.6MHz -  = 0.20, L = 350km, v = 200m/s

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 16 Simulation Results 10.6MHz -  = 0.20, L = 350km, v = 200m/s

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 17 Simulation Results 10.6MHz -  = 0.20, L = 350km, v = 200m/s

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 18 Comparison – Experimental Results Signals from Jindalee Radar transmitter in Alice Springs Dual- polarization receiver in Darwin

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 19 Experimental Results Finding the signal component along each sweep FMCW Radar signal

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 20 Experimental Results 6:30PM local time – Spectrograms

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 21 Experimental Results 6:30PM local time – Time fading

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 22 Experimental Results 6:30PM local time – Frequency fading

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 23 Experimental Results 7:30PM local time – Spectrograms

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 24 Experimental Results 7:30PM local time – Time fading

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 25 Experimental Results 7:30PM local time – Frequency fading

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 26 Fading Separation Separate amplitude and polarisation fading Two orthogonal antennas: A - amplitude component  - phase component Therefore:

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 27 Fading Separation 7:30PM local time – Time fading revisited

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 28 Fading Separation 7:30PM local time – Time fading separation

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 29 Fading Separation 6:30PM local time – Time fading revisited

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 30 Fading Separation 6:30PM local time – Time fading separation

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 31 Fading Separation Fading separation works well for single- mode case For multi-mode propagation:  Exploit FMCW radar signals  Separating the modes using Range-gating techniques  Applying fade separation to each of the modes

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 32 Discussion Further analyzing with experimental data Comparisons with ionosonde data  Discover the structure of the ionosphere during the period of rapid fading  Simulating propagation under realistic irregularity strctures Possible applications:  Real-Time channel evaluation  Test-bed for fading mitigation techniques

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 33 Conclusion Efficient Ionospheric Propagation Simulator has been developed Experiment to observe fading of HF signals was done successfully Comparisons between experiment and simulation are promising, especially for single-path polarization fading More work to be done on the experimental data

An Efficient Ionospheric Propagation Simulator for High Frequency Signals - Page 34 Acknowledgements Defence Science and Technology Organisation (DSTO) Dr. Manuel Cevira Dr. Chris Coleman