RTCM 10403.2
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PREFACE
This standard has been developed by RTCM Special Committee 104 as a more efficient
alternative to Version 2 in various documents entitled "RTCM Recommended Standards for
Differential Navstar GPS Service, Version 2.x”. Service providers and vendors represented on
the SC-104 Committee requested the development of a new standard that would be more
efficient, easy to use, and more easily adaptable to new situations. The main complaint was that
the Version 2 parity scheme, which uses words with 24 bits of data followed by 6 bits of parity,
was wasteful of bandwidth. Another complaint was that the parity was not independent from
word to word. Still another was that even with so many bits devoted to parity, the actual
integrity of the message was not as high as it should be. Plus, 30-bit words are awkward to
handle. This standard, Version 3, is intended to correct these weaknesses.
Unlike Version 2, the Version 3 standards do not include tentative messages. The messages in
Version 3 have undergone testing for validity and interoperability, and are considered to be
permanent. Future modifications of the standard may change the meaning of reserved bits or
provide additional clarifying text, but no changes will be made in the data fields. Changes will
require new messages to be developed. As new messages and capabilities have been
demonstrated through validity and interoperability testing, they will be incorporated into future
revisions of the Version 3 standard, either as amendments or as a new revision of standard
10403.x. Amendments will be made available electronically to those who have purchased the
standard. Periodically, accumulated Amendments will be incorporated into a complete revision
of standard 10403.x.
RTCM SC-104 believes that Standard 10403.2 for DGNSS services will continue to prove useful
in supporting highly accurate differential and kinematic positioning as well as a wide range of
navigation applications worldwide throughout the next decade.
© RTCM – Not for reproduction or redistribution
