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                    Document headings vary by document type but may contain                    the following:                  
                -                       the agency or agencies that issued and signed a document                    
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###### Department of Defense

###### Department of the Air Force 

# AGENCY:

Department of the Air Force, DoD. 

# ACTION:

Notice and request for review/comment of changes to ICD-GPS-200C. 

# SUMMARY:

                        This notice informs the public that the Global Positioning System (GPS) Joint Program Office (JPO) proposes to revise ICD-GPS-200, Navstar GPS Space Segment/Navigation User Interfaces. This proposal changes the document identifier from ICD-GPS-200 to Interface Specification (IS)-GPS-200. In addition, this revision will increment the revision letter from C to D, resulting in IS-GPS-200 Revision D. One of the main subjects of this revision effort is an introduction of new Improved Clock & Ephemeris (ICE) navigation message that will be broadcast with L2 C signal. These proposed changes are described in a Draft IS-GPS-200D, dated 9 July 2004. This draft document is an updated version of the draft document previously released in February 2004. The draft document can be viewed and downloaded at the following Web site:                         *http://gps.losangeles.af.mil*. Click on “System Engineering”, then “Public Interface Control Working Group (ICWG)”. Reviewers should save the document to a local memory location prior to opening and performing the review.                     

# ADDRESSES:

                        Submit comments to SMC/GPERC, 2420 Vela Way, Suite 1467, El Segundo CA 90245-4659. A comment matrix is provided for your convenience at the web site and is the preferred method of comment submittal. Comments may be submitted to the following Internet address:                         *smc.gperc@losangeles.af.mil*. Comments may also be sent by fax to 1-310-363-6387.                     

# DATES:

The suspense date for comment submittal is 30 October 2004. 

# FOR FURTHER INFORMATION CONTACT:

GPERC at 1-310-363-2883, GPS JPO System Engineering Division, or write to the address above. 

# SUPPLEMENTARY INFORMATION:

The civilian and military communities use the Global Positioning System, which employs a constellation of 24 satellites to provide continuously transmitted signals to enable appropriately configured GPS user equipment to produce accurate position, navigation, and time information. 

Pamela D. Fitzgerald,

Air Force Federal Register Officer. 

[FR Doc. 04-21366 Filed 9-22-04; 8:45 am] 

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