Please contact Paul Withers (withers@bu.edu) with any questions concerning this package. This software was developed on a Linux machine.

aareadme.txt - Description of contents of package
8361M48A.EDS - Archived electron density profile for this occultation, from the PDS
8361m48a.tps - Archived neutral atmospheric profile for this occultation, from the PDS
mgs83611248refprof.dat - Derived refractivity profile, from Dave Hinson. Column 1 is planetocentric radius in m.  Column 2 is refractive index minus one. 
mn83611248resids25xr01_short.dat - MGS frequency residuals file, from Dave Hinson, format described below
radio_occ_mgs_v18.pro - IDL program used to convert frequency residuals into atmospheric and ionospheric profiles
results.txt - Table of atmospheric and ionospheric profiles and other information generated by radio_occ_mgs_v18.pro
results.sav - IDL save file containing atmospheric and ionospheric profiles and other information generated by radio_occ_mgs_v18.pro

Required generic and other SPICE files that are not included in the package
de414.bsp - SPICE file - http://naif.jpl.nasa.gov/pub/naif/generic_kernels/spk/planets/a_old_versions/
earth_720101_070426.bpc - SPICE file - http://naif.jpl.nasa.gov/pub/naif/generic_kernels/pck/
earthstns_fx_050714.bsp - SPICE file - http://naif.jpl.nasa.gov/pub/naif/generic_kernels/spk/stations/
EARTH_TOPO_050714.TF - SPICE file - http://naif.jpl.nasa.gov/pub/naif/generic_kernels/fk/stations/
mgs_ab2.bsp - SPICE file - http://naif.jpl.nasa.gov/pub/naif/pds/data/mgs-m-spice-6-v1.0/mgsp_1000/data/spk/
naif0009.tls - SPICE file - http://naif.jpl.nasa.gov/pub/naif/generic_kernels/lsk/a_old_versions/
pck00009.tpc - SPICE file - http://naif.jpl.nasa.gov/pub/naif/generic_kernels/pck/a_old_versions/

Step-by-step instructions are as follows.
Start of step-by-step instructions

1. Ensure IDL and SPICE are running on your computer.

2. Place all files in a single directory and make a copy of the entire directory for backup purposes.

3. Compile radio_occ_mgs_v18.pro. Expected output on screen is:
IDL> .run radio_occ_mgs_v18
% Compiled module: RADIO_OCC_MGS_V18.
% Compiled module: NONRELBROYFUNC.
% Compiled module: RELBROYFUNC.

4. Run radio_occ_mgs_v18.pro. For reference, runtime on my desktop is less than 10 seconds. Expected output on screen is:
IDL> radio_occ_mgs_v18     
Start of program

% Loaded DLM: ICY.
Finished defining physical constants and acquiring basic SPICE kernels

Finished ingesting MGS frequency residuals

Finished ingesting archived atmospheric and ionospheric profiles

About to begin loop to find bending angle and impact parameter for each time step
This may take some time, add a "print, iobs" line inside the loop if more information desired

% Compiled module: NORM.
Finished loop to find bending angle and impact parameter for each time step

% Compiled module: REVERSE.
% Compiled module: INTERPOL.
Finished obtaining refractive index profile

% Loaded DLM: JPEG.
% Compiled module: POLY_FIT.
Finished finding neutral atmospheric profile

About to begin making series of EPS plots

% Compiled module: ARROW.
% Compiled module: STDDEV.
% Compiled module: MOMENT.
Finished making series of EPS plots

End of program

% Stop encountered: RADIO_OCC_MGS_V18 1422
   /deimos/deimos_backup/olddeimos00/spice/icy/freqresidsoln/radio_occ_mgs_v18.pro

5. The expected output also includes 8 onscreen plots and 23 EPS plots. If IDL is unable to find the functions nonrelbroyfunc and relbroyfunc, which are at the end of the radio_occ_mgs_v18.pro procedure, despite successfully compiling them, then try saving them as separate programs nonrelbroyfunc.pro and relbroyfunc.pro.

6. Examine the final pieces of output, results.txt and results.sav, and compare against those provided in the original distribution.

End of step-by-step instructions


Email message from Dave Hinson to Paul Withers on 2011.04.25 concerning MGS frequency residuals that describes format of his MGS frequency residuals file

I've attached a file containing frequency residuals from the entry side of one MGS radio occultation experiment on 27 Dec 1998 (day 361 of 1998).  It's an ascii file with four columns:
   1) Earth receive time in seconds past midnight (UTC);
   2) frequency residual (Hz);
   3) signal power (linear, arbitrary units)
   4) approximate distance between raypath and center of Mars (km).  
The ground antenna was DSS 25.