User`s guide

8-5
Compatibility Considerations
In previous releases, the inverse flattening value used to calculate eccentricity was
truncated and therefore less precise.
Note: When 'airy' is used, almanac returns an ellipsoid vector for the Airy 1830
reference ellipsoid. This has always been the case and has not changed in R2011b,
but through R2011a the documentation incorrectly indicated that 'airy' was the
designation for the Airy 1849 reference ellipsoid. In R2011b this documentation error
has been corrected. There is no Airy 1849 option in almanac, but if you need to you can
construct an ellipsoid vector for the 1849 ellipsoid as follows:
[6377.340189 flat2ecc(1/299.3249646)]
In this case, the semi-major axis length is given in kilometers, which is consistent with
the length unit default of almanac.