4 ms·

It's achingly beautiful to the pocket protector set (me!). This source code, for example, contains the very first Kalman filter ever used - Kalman was invited

by RogerL 12y ago

It's achingly beautiful to the pocket protector set (me!). This source code, for example, contains the very first Kalman filter ever used - Kalman was invited over to Moffett field to give talks about his paper, which led to his theory was used in LM code. But I think everyone is very aware of the state of the art at the time, and things have advanced a lot since then. It is impressive to see them cramming that into such a limited processor. But, 'whatever' as to that aspect of it. This is a historical artifact of an amazing feat based on cutting edge research in mathematics/control theory.

hcrisp 12y ago
Wasn't it the PGNCS that had the Kalman filter? See my comment nearby which confused it with AGC.
- RogerL 12y ago
  It is my understanding that the AGC is the computer within the PGNCS. Terminology varies, as the last link below from NASA notes. So far as I can tell, the AGC maintained the state vectors for the KF. Ground control would run batch mode least squares solutions, and pass it on to the LM, where the updates to the state vector would be applied by hand. I freely admit to not having worked through the code, but I believe the state vector update computations occur here: http://www.ibiblio.org/apollo/listings/Comanche055/MEASUREMENT_INCORPORATION.agc.html http://www.ibiblio.org/apollo/listings/Comanche055/MEASUREME... sources: http://www.ieeecss.org/CSM/library/2010/june10/11-HistoricalPerspectives.pdf http://www.ieeecss.org/CSM/library/2010/june10/11-Historical... http://en.wikipedia.org/wiki/Apollo_Guidance_Computer http://en.wikipedia.org/wiki/Apollo_Guidance_Computer http://en.wikipedia.org/wiki/Apollo_PGNCS http://en.wikipedia.org/wiki/Apollo_PGNCS http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090016290.pdf http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2009001...
  - hcrisp 12y ago
    Thanks, that helps. I've always wondered what the variables of the state vector were -- position, velocity, etc. it appears from the link that it could be a 6x6 of those two (position, velocity in x, y, and z), or a 9x9 when including radar/landmark bias. Now I know!

by RogerL 12y ago

hcrisp 12y ago

Wasn't it the PGNCS that had the Kalman filter? See my comment nearby which confused it with AGC.

RogerL 12y ago
It is my understanding that the AGC is the computer within the PGNCS. Terminology varies, as the last link below from NASA notes. So far as I can tell, the AGC maintained the state vectors for the KF. Ground control would run batch mode least squares solutions, and pass it on to the LM, where the updates to the state vector would be applied by hand. I freely admit to not having worked through the code, but I believe the state vector update computations occur here: http://www.ibiblio.org/apollo/listings/Comanche055/MEASUREMENT_INCORPORATION.agc.html http://www.ibiblio.org/apollo/listings/Comanche055/MEASUREME... sources: http://www.ieeecss.org/CSM/library/2010/june10/11-HistoricalPerspectives.pdf http://www.ieeecss.org/CSM/library/2010/june10/11-Historical... http://en.wikipedia.org/wiki/Apollo_Guidance_Computer http://en.wikipedia.org/wiki/Apollo_Guidance_Computer http://en.wikipedia.org/wiki/Apollo_PGNCS http://en.wikipedia.org/wiki/Apollo_PGNCS http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090016290.pdf http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2009001...
- hcrisp 12y ago
  Thanks, that helps. I've always wondered what the variables of the state vector were -- position, velocity, etc. it appears from the link that it could be a 6x6 of those two (position, velocity in x, y, and z), or a 9x9 when including radar/landmark bias. Now I know!