G - I
In 1962 the ILS was renamed the International Polar Motion Service (IPMS) and in 1988 the IPMS was discontinued when the International Earth Rotation Service commenced. During its history the ILS/IPMS provided valuable observations of polar motion which continue to be analyzed today. Information provided by http://igscb.jpl.nasa.gov/mail/igsmail/1998/msg00249.html
IPMS