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.
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