Issue of Data, Clock (IODC) Value Selection Process and IS-GPS-200H Compliance

U.S. Coast Guard sent this bulletin at 12/20/2017 02:37 PM EST
united states coast guard

All CGSIC:

    The Air Force has released a memorandum  which informs the GPS community of an IS-GPS-200H compliant change to the Issue of Data, Clock (IODC) value selection process in the GPS control segment software.  The IODC values will now be any numbers in the range 0 to 1023 to support requirements in IS-GPS-200H paragraph 20.3.4.4.  Historically, the IODC values were typically chosen from the range 0 to 255.  This IS-GPS-200H compliant change to the IODC selection process will be reinstalled in a later update to the GPS software no earlier than 01 Mar 2018.  The full memo has been posted to the U.S. Coast Guard Navigation Center website at https://www.navcen.uscg.gov/pdf/gps/IODC_Change_Letter_SIGNED_v2_20171220.pdf

V/R

Rick Hamilton

CGSIC Executive Secretariat

GPS Information Analysis Team Lead

U.S. Coast Guard Navigation Center

703-313-5930