A general symmetry-preserving observer for aided attitude heading reference systems.

Philippe Martin Erwan Salaün A general symmetry-preserving observer for aided attitude heading reference systems. 2294-2301 2008 CDC http://dx.doi.org/10.1109/CDC.2008.4739372 conf/cdc/2008 db/conf/cdc/cdc2008.html#MartinS08