This standard amendment is motivated by a European, Japanese, and US need to support early pilot deployments using the MAP and SPAT messages which will occur in 2014. The committee wishes to reflect in this standard various improvements determined by developing requirements and field testing over the past 3 years. In this amendment, we therefore incorporate a number of additional desired features into the message structures which these trials have exposed.
We publish this amendment before an anticipated revision of the entire document, work on which will begin immediately after publication of this amendment. The committee is aware of a number of other areas in the document which will also require consideration at that time, including updating references of other standards to the latest versions. (Where such documents existed, the versions of standards referenced in the body of this document were the ones available at the time of publication of the Nov 2009 revision.)
Our expectation is that the replacement portions that address with MAP and SPAT will coexist with the rest of the document, and that entire document can therefore be used in early deployment until it is reissued with further changes and additional content. The committee also stresses that the unamended portions and messages defined in the document remain standardized and normative.