an efficient propagation simulator for high frequency signals and results from hf radar experiment
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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. Overview. - PowerPoint PPT PresentationTRANSCRIPT
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
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Introduction
HF radio system is still prevalent Military Over-the-Horizon RADAR HF communications Commercial broadcasting
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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
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Lower path – Extraordinary waveRight-hand circular
polarisation
Upper path – Ordinary wave
Left-hand circular polarisation
Polarization Fading Model
Faraday rotation due to O and X wave interference
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Polarization Fading Model
Perturbation techniques to ascertain the change in phase path due to irregularities
dgdsPdunperturbedunperturbe
Use of frequency offset method to take into account of the magnetic field
Hxo fff cos2
1,
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Amplitude Fading Model Focussing and defocussing of radio
waves due to movement of large scale ionospheric structure
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Amplitude Fading Model
Parabolic approximation to Maxwell’s equation (Wagen and Yeh):
0),(2 22
Utgkt
U
g
Ukj oo
U is the complex amplitude, is the refractive index with irregularities
g and t are the local longitudinal and transverse coordinates
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Amplitude Fading Model
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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
Ionospheric condition information
Simulation parameters
Ray Tracing Engine(RTE)
Polarisation Fading Model(PFM)
Amplitude Fading Model(AFM)
Ionospheric Propagation Simulator(IPS)
Data Display Module
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Simulation Results
Alice Springs to Darwin
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Simulation Results 10.6MHz - = 0.05, L = 350km, v = 200m/s
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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
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Simulation Results 10.6MHz - = 0.20, L = 350km, v = 200m/s
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Simulation Results 10.6MHz - = 0.20, L = 350km, v = 200m/s
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Simulation Results 10.6MHz - = 0.20, L = 350km, v = 200m/s
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Comparison – Experimental Results
Signals from Jindalee Radar transmitter in Alice Springs
Dual-polarization receiver in Darwin
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Experimental Results
Finding the signal component along each sweep
FMCW Radar signal
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Experimental Results
6:30PM local time – Spectrograms
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Experimental Results
6:30PM local time – Time fading
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Experimental Results
6:30PM local time – Frequency fading
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Experimental Results
7:30PM local time – Spectrograms
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Experimental Results
7:30PM local time – Time fading
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Experimental Results
7:30PM local time – Frequency fading
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Fading Separation
Separate amplitude and polarisation fading Two orthogonal antennas:
)),(cos(),( tftfAVH )),(sin(),( tftfAkVV A - amplitude component
- phase component Therefore:
H
V
Vk
Vtan )tan1( 222 HVA
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Fading Separation
7:30PM local time – Time fading revisited
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Fading Separation
7:30PM local time – Time fading separation
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Fading Separation
6:30PM local time – Time fading revisited
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Fading Separation
6:30PM local time – Time fading separation
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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
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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
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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
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Acknowledgements
Defence Science and Technology Organisation (DSTO)
Dr. Manuel Cevira Dr. Chris Coleman