Bachelor Thesis - HFIA · Bachelor Thesis German Title: „Untersuchung eines 'ray tracing'...

transcript

Bachelor Thesis

German Title: „Untersuchung eines 'ray tracing' Programms auf seine Eignung für die Kurzwellenfunk-Ausbreitungsprognose“

Structure of Presentation

• Task of the Thesis

• Proceeding

• Summary of relevant results

• Discussion

Task of the Thesis

In German:

„Detaillierte Untersuchungen des 'ray tracing' Programms 'Proplab-Pro 3.0' auf seine Eignung für die professionelle Kurzwellenfunk- Ausbreitungsprognose“

In English:

“Detailed Examination of the ray tracing Software 'Proplab-Pro 3.0' on its suitability for the professional forecast of HF-radio propagation”

Proceeding

• Study of ionospheric HF-propagation basics

• Manual calculation of a representative HF-link

• Study of "Ray Tracing" basics

• Comparison of three propagation simulation SW "PropWiz", "RPPUE" and "Proplab-Pro 3.0" w.r.t.

• Features

• "Truth" of results

Basics

Ionospheric HF-Propagation

Basics of Ionospheric HF-Propagation

HF propagation modes:

• Groundwave

• Skywave

Skywave propagation paths:

HF skywave propagation via ionosphere depends on the following factors:

• Time of day

• Season

• Geographic location

• Solar activity

• Frequency

• Antenna elevation radiation angle, corresponding with angle of incidence of the wave into the ionospheric layer

Ionospheric layers:

•F-layer (subdivided in F2- and F1-layer)

•E-layer

•D-layer

Manual Calculation of a representative HF-Link

Calculation of the usable frequency range for two exemplary paths:

1st path: Munich – Hamburg

2nd path: Munich – Hong Kong

Both paths were calculated for the points in time

July 2012 and

January 2013

Path Munich – Hamburg:

"Ray Tracing" Basics

Basically the term "ray tracing" in English language is self explanatory.

Somewhat more in detail it means:

• Emitted electromagnetic waves are described by "ray tracing" using idividual rays

• The course of the rays is simulated obeying physical laws, angle of emission, diffraction and absorption

• In this way the various incident points of the wave at the ionosphere and at ground are found

"Ray Tracing" Basics

In the "Proplab-Pro 3.0" software the "ray tracing" model

• calculates how the signals penetrate the ionosphere and propagate in it. Penetration and diffraction are the keywords

• traces each ray individually using a dynamic, very complex model of the ionosphere

• allows for the actually existing ionospheric conditions

"Ray Tracing" Basics Characteristics of the "ray tracing" models in "Proplab-Pro 3.0":

2D-Model 3D-Model

Computing time Fast Suitable for real time analysis

Boring slowly Calc. time: Days to weeks

Accuracy High Very high

Including … Oblique ground reflections - -

Absorptions by the ionosphere

- Oblique ionosphere layers

Magnetic field effects Absorptions by the ionosphere

Graphic result diagram shows ...

Elevation Frequency

Elevation Frequency Azimuth

Comparison of three Propagation Simulation SW

"PropWiz", "RPPUE" and "Proplab-Pro 3.0"

as well as

Manual Calculation

Overview of "Proplab-Pro 3.0", "PropWiz 1.7" and "RPPUE

4.28" Proplab-Pro PropWiz RPPUE

Proplab-Pro Propagation

Wizard

RPPUE, Program for

calculation of HF

Radio Propagation

Predictions

Supplier Solar Terrestrial

Dispatch

Rohde & Schwarz Dr. Thomas Damboldt

Telecommunications

Version Version 3.0 Version 1.7 Version 4.28

Features of "Proplab-Pro 3.0"

Analysis of Results

Comparisons between:

1. Basic Data

2. MUF resp. FOT

3. SNR

4. Fieldstrength resp. signal strength at Rx site

5. Availability resp. reliability of commline

Analysis of Results

1. Basic Data e.g.

– Site Coordinates

– Distance

– Azimuth of Tx- resp. Rx- antennas

– Minimum number of required hops

Result:

No relevant differences between examined programs

Analysis of Results

2. MUF resp. FOT comparisons shown for the 2nd exemplary path Munich - Hong Kong in July 2012

Result: RPPUE results show very good coincidence with manual

calculation PropWiz calculates more pessimistic (i.e. lower) MUF-

values (deviations up to 3.7 MHz) Proplab-Pro 3.0 shows clear differences (deviations 2,5

MHz to 6.9 MHz) → MUF determination by "ray tracing" → more actual and precise resultats

MUF as calculated by PropWiz

MUF as calculated by RPPUE

MUF as calculated by Proplab

Analysis of Results

3. SNR-comparison shown for the 2nd exemplary path Munich - Hong Kong in July 2012

Result:

SNR available only for PropWiz und RPPUE

Course of SNR over time is identical for both programs

S/N absolute values and associated frequencies, however, exhibit major differences

→ algorithms used resp. databases are different

→ Antenna radiation patterns are evaluated with different precision

Analysis of Results

4. Comparison of Fieldstrength resp. Signalstrength at Rx site shown for the 2nd exemplary path Munich - Hong Kong in July 2012 Result

Available only with programs RPPUE and Proplab-Pro 3.0 Quick and easy fieldstrength determination with RPPUE Proplab-Pro 3.0: rough determination of areas having high

or low signalstrengths; bad recognition of colors and hence signalstrengths; obvious occurence of quantization errors

Fieldstrength as calculated by RPPUE

Proplab-Pro 3.0 – Settings

Proplab-Pro 3.0 – Broadcast Coverage Map

Proplab-Pro 3.0 – Zoomed Broadcast Coverage Map

Analysis of Results

5. Comparison of Availability resp. Reliability shown for the 2nd exemplary path Munich - Hong Kong in July

Results: Available only with PropWiz und RPPUE PropWiz is determining the availabilty on the basis of the SNR RPPUE does this on a more lavish way considering technical

boundary conditions and statistical fluctuations within a month

Further Differences are to be traced back by the utilization of different databases

Further Analysis Tools contained in "Proplab-Pro 3.0"

„Proplab-Pro 3.0“ comes with three analysis tools :

• Ray Location Map

• Broadcast Coverage Map (already introduced in context with signal strength analysis)

• Oblique Sounder Ionogram

Ray Location Map

Oblique Sounder Ionogram – Settings

Oblique Sounder Ionogram – Elevation Angle Plot-

Oblique Sounder Ionogram -Propagation Delay Plot-

Summary of relevant Results

I. Anforderungen des Benutzers müssen ersichtlich sein

II. Programm auswählen, welches am besten zu den gestellten Ansprüchen passt

III. Vorgehen bei der Auswahl: Analysepunkte sowie Features der Programme auf ihre Wichtigkeit für den Anwender überprüfen

IV. Programm auswählen, welches die meisten Punkte und Features für den Anwender bereitstellt

Manual Calculation: The old fashioned, maybe quite accurate, method is nice for getting started and to acquire a basic understanding. Due to the immense time needed, this method nowadays has to be regarded as "pure academic". PS: In the course of our studies we found out that some old but valuable ITU (CCIR/CCITT) documentation is available only in antiquarian form

PropWiz and RPPUE: Both programs deliver quick results an are rather simple to be operated. The training period for RPPUE will be longer as compared to PropWiz but due to a more complex algorithm the results will be more precise - and ... more colorful. PS: The antenna database for both programs is of paramount importance with respect to to the meaningfulness of the results.

Proplab-Pro 3.0:

– Substantial training period required

– Many features

– Highest accuracy of all due to complex ionosphere-model and application of ray tracing method

– Quantization errors observed

– 3D-model with PCs available at that time due to extreme calculation time not applicable

Many Thanks for your Attention!

Discussion

Manually

Proplab-Pro

Propwiz

Bachelor Thesis - HFIA · Bachelor Thesis German Title: „Untersuchung eines 'ray tracing'...

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