Not sure where I have read that for the first time but, at very least, I perhaps know about it since the Soyuz Guidance MFD has been released for Orbiter simulator (ho no, here he goes again!
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Soyuz Guidance MFD allows for automatic orbital operations and, in its very interesting documentation (the manual has a really nice schematic diagram of the burns made to achieve a rendezvous) the rotating pads were mentioned as well it was provided a list about launch headings vs orbital inclinations (and some nice excel files) so that we can properly prepare our virtual missions. Unfortunately, unless I'm missing something, it seems that this particular part of the documentation (considerations about the algorithm and math behind it) has been removed from later add-on versions and I'm not able to find the digital version (only have the printed pages). If someone is really interested on that part of the pdf documentation maybe the best is to contact the author.
The chapters were:
1. How to use the guidance system
1.1) Introduction
1.2) Setting the orbital inclination
Quote:
"(…)Because Soyuz rockets are mounted on rotating launch pads that put the ship on the correct heading (azimuth) for launch if you want change the inclination of the orbit you will need to alter the initial heading of the Soyuz in the scenario file. What heading to set the Soyuz for a given inclination is given in by table in Section 4 on page 9. Alternatively you can calculate the correct azimuth using equations 12 and 13 (Section 3.3.1)(…)"
2. Where to find the source code (it is included with the add-on)
3. How the guidance system works
3.1) Pitch control
3.2) Control at MET > 490 sec
3.3) Heading control
3.3.1) The true course setpoint
3.3.2) True course deviation
3.3.3) Orbit inclination deviation
3.3.4) Combining the deviations
4. Launch Azimuths for Baikonur
5. The pitch Lookup table
6. Questions or comments
Anyway, just for reference - maybe of interest for some – the download Links for Soyuz Guidance can be found in its home page:
http://www.massey.ac.nz/~rjcroy/António
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