Ray Tracing Through the IONOSPHERE

FORTRAN Code

 

Ray Tracing Through the IONOSPHERE Open Source Mathematica ® Code Click Here.

For Description Click Here

Case	Description	Code	Result Plots
1	FORTRAN Code for Ray Tracing Radio Waves Through the IONOSPHERE. Cleaned up and debugged from Scan and OCR of [Jones, Stephenson, 1975] Original CDC Mainframe FORTRAN. Compiles with gfortran. Note: Use a Professional Compiler until some issues with gfortran need to be resolved.	FORTRAN (7.7 MBytes)	Ray Trace Multiple Elevations Fixed Bounds
2	Ray Trace Results Plotted		Individual Plots Grouped
	Parameter text file. Place in same directory as FORTRAN Executable.	ray.dat	--
3	Latex File for Hamiltonian, Derivatives and Symbol Table	Latex File

 

Tools

Item	Description	Code	WEB View	Graphic
1	Java Open Source Plotting Package ( IIPPLOT)	CCDSP	--	Ray Tracing

References:

1- R. Michael Jones, Judith J. Stephenson, A Versatile Three-Dimensional Ray Tracing
Compute Program for Radio Waves in the Ionosphere, OT Report 75-75, US Department of Commerce, October 1975 PDF Report.

Description

 

FORTRAN Code from Scanned Report (OT Report 75-76) and OCR in 2002 by Sasan Ardalan

Compiles and Links using gfortran

Rework in December 2018 by Sasan Ardalan

Detailed work to match source code with published code. Major work to change from CDC Main Frame Fortran to gfortran.

Massive effort in debugging.

Also debug option for printing of variables. See nitial.f

This FORTRAN Code available at:

http://www.radiocalc.com

Visit the site for plots of raytracing.

Also translation to Mathematica by Sasan Ardalan. Click here for Mathematica Code.

PERL Script and Plotting

We have also included the handy PERL script:

process_raytracing.pl

This is in the Results folder.

Execute:

./raypath <ray.dat> results.txt

Edit results.txt to get data for a trace ( say at 45 degrees elevation). Call it result_45.txt

perl process_raytracing.pl < result_45.txt> ray_trace_45.txt

Plot the result. Use

java -jar IIPPLOT.jar ray_trace_45.txt

See here for IIPPLOT Open Source Plotting Package.

Note that we added the text "uu" to each relavant line in the FORTRAN results so that the line can be grabbed with PERL and the Height and Range extracted (and Swapped) to plot the ray trace.

Notes on FORTRAN Code

1. Had to change SSTEP error in reach.f to 0.5E-3 so that elevation angles below 30 degrees work ( 15 and 0).
2. Results follow the OT Report 75-76, however do not match which could be for a number of reasons. Need to verify that models are exactly the same.
3. At close to and including elevation of 90 degrees results are off when wave reversus. The range starts to decrease
4. If we continue to debug it would never end and you would not be reading this.
5. GFORTRAN needs to be checked against a commercial or another FORTRAN complier.
6. Cases where gfortran doing something or not doing something for no good reason.
7. Will try and document and submit to GFORTRAN group.
8. Check nitial.f for some hardwired values ( W values ignored).
9. Added COMMON /RK/ DELY ,BET ,XV ,FV ,YU ,RR,LL,MM,ALPHA,EPM to rkam.f and trace.f this was a major change since original CDC FORTRAN must have assumed variable persistance between subroutine calls.
10. In CDC FORTRAN DRDT(1) was set using only DRDT. Fixed this in hamltn.f

Note in FORTRAN Elevation of 90 Degrees is Vertical Launch.

Hamiltonian

 

Spherical Coordinates

 

Hamiltonian and Derivatives

Ray Vector

Ray Vector Options