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=== TAEM/Approach guidance algorithm === | === TAEM/Approach guidance algorithm === | ||
{{note|Full explanations about | {{note|Full explanations about TAEM and Approach/Autoland guidance might be found there: [[Shuttle guidance - TAEM/Approach and Autoland guidance]]}} | ||
This section speaks about TAEM and Autoland guidance. | |||
'''Documentations''' | |||
*Space Shuttle TAEM guidance code sum up: [https://ntrs.nasa.gov/citations/19920010688] | |||
*TAEM/Approach Handbooks there: [https://forum.flightgear.org/viewtopic.php?f=87&t=38777] | |||
'''Overview''' | |||
The last link mentionned above is pretty interesting to see the evolution of TAEM guidance and how it was handled. | |||
The main document I used include the Optional TAEM Targeting (OTT) logic that has been used since STS-5 (before the HAC was a circle with less Energy options for test flights). | |||
After STS-5, HAC could be flown with the different options we are used to see . | |||
Overhead or Straight-In HAC; and Nominal Entry Point (7Nm in final) or Minimal Entry Point (4Nm in final) | |||
[[File:OTT option.webp|600px|thumbnail|none]] | |||
Another option called - final radius shrinking - is included in that TAEM guidance version. | |||
It allows the final HAC radius (2.3 Nm) to decrease up to 0.8 Nm if we are low during the HAC. | |||
[[File:Spiral hac.webp|600px|thumbnail|none]] | |||
The whole logic is organized through several functions that are called during all the TAEM phase at a rate between 160 and 980ms. | |||
It ends at 10000 feet (Approach and Landing interface) where the Auto Land logic kicks in (quite the same logic with tighter gains). | |||
[[File:TAEM flow logic.webp|600px|thumbnail|none]] | |||
Let's go briefly through each functions. | |||
The first function that is not mentionned is a frame coordinate converter from a Greenwhich frame into a runway centered frame. | |||
[[File:TAEM runway coordinate system.webp|600px|thumbnail|none]] | |||
== Avionics and DPS == | == Avionics and DPS == | ||