[Federal Register Volume 75, Number 58 (Friday, March 26, 2010)]
[Notices]
[Pages 14658-14659]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-6814]
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DEPARTMENT OF TRANSPORTATION
Research and Innovative Technology Administration
Invitation for Public Comment on Mitigation Options for Global
Positioning System Satellite Vehicle Number 49
AGENCY: Research and Innovative Technology Administration, DOT.
ACTION: Notice, request for public comments.
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SUMMARY: The U.S. Government is providing notice that it is actively
considering several mitigation options prior to changing the health
status of Global Positioning System (GPS) satellite IIR-20M (satellite
vehicle number 49--SVN 49) from unhealthy to healthy. The potential
mitigations are each designed to reduce the impact of the unique nature
of the SVN 49 signal to a portion of the user segment. The mitigations
are described in an Appendix posted in the public docket. The
mitigations are intended only for use with the SVN 49 satellite and
will not be implemented for any other GPS satellite. Responses from
this public comment period will be considered during the final decision
to choose which mitigation(s) to implement.
After successful implementation of the selected mitigation(s), U.S.
Government leaders will determine the conditions necessary to set SVN
49 healthy. It is anticipated this timeline will occur over the next
one to three years. Please review the posted Appendix and submit
concerns or adverse impacts that may affect your user equipment to the
Docket.
Two teleconferences will be hosted by the U.S. Air Force GPS Wing
to discuss the mitigation options. These will be held on March 26, 2010
and April 30, 2010 at 4 PM EDT. The teleconference number is 1-800-366-
7242 passcode: 6530000. Please note that if you want a
specific comment made during either telephone conference included in
the docket, you must submit a public comment to the docket as outlined
below.
DATES: Comment Period: Written comments should be submitted by May 28,
2010.
ADDRESSES: You may submit comments identified by RITA Docket ID Number
RITA 2010-0002 by any of the following methods: Federal eRulemaking
Portal: Go to http://www.regulations.gov. Follow the online
instructions for submitting comments.
Mail: Docket Management Facility: U.S. Department of
Transportation, 1200 New Jersey Avenue, SE., West Building Ground
Floor, Room W12-140, Washington, DC 20590-0001.
Hand Delivery or Courier: West Building Ground Floor, Room W12-140,
1200 New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m.
ET, Monday through Friday, except Federal holidays.
Fax: 202-493-2251.
Instructions: Identify docket number, RITA 2010-0002, at the
beginning of your comments. To receive confirmation that DOT received
your comments, include a self-addressed stamped postcard containing the
Docket number.
All comments received by DOT will be posted at http://www.regulations.gov.
All comments/questions will be posted electronically without change
or edits, including any personal information provided.
Privacy Act: Anyone is able to search the electronic form of all
comments/questions filed in our dockets by the name of the individual
submitting the comment or question (or signing the comment, if
submitted on behalf of an
[[Page 14659]]
association, corporation, business entity, labor union, etc.). You may
review DOT's complete Privacy Act Statement in the Federal Register
published on April 11, 2000 (65 FR 19477-78) or you may visit http://DocketInfo.dot.gov.
Confidential Business Information: If you wish to submit any
information under a claim of confidentiality, you should submit three
copies of your complete submission, including the information you claim
to be confidential business information, to the address given below
under FOR FURTHER INFORMATION CONTACT. In addition, you should submit a
copy from which you have deleted the claimed confidential business
information to the docket. When you send a comment containing
information identified as confidential business information, you should
include a cover letter setting forth the reasons you believe the
information qualifies as ``confidential business information''. (49 CFR
7.17)
FOR FURTHER INFORMATION CONTACT: Ms. Karen Van Dyke, DOT/RITA, 1200 New
Jersey Ave., SE., Washington, DC 20590, 202-366-3180,
[email protected] or Lt. Col. James Lake, 310-653-3613,
[email protected].
SUPPLEMENTARY INFORMATION:
Background
The GPS satellite SVN 49 has a unique signal that may result in
degraded performance for some GPS user equipment. This satellite
currently operates with the navigational message set in an unhealthy
state to prevent any adverse impact to users. To minimize the adverse
impacts, several mitigations are under consideration. Each mitigation
is intended for a specific user group and can be used with or without
the other mitigations. All mitigations are intended for use with SVN 49
only and no changes will be made regarding other GPS satellites. The
mitigations are briefly described as:
Set SVN 49 healthy with current 152m Antenna Phase Center
(APC) and associated clock offsets.
Set SVN 49 healthy with factory default APC and clock
offset.
Users switch to multipath-resistant receivers to minimize
adverse impact from SVN 49 signal.
Modify receiver software to use look-up table corrections
to account for unique SVN 49 signal.
Increase SVN 49 User Range Accuracy (URA) minimum value to
3 by changing bits in the GPS data message that allow user equipment to
de-weight or exclude SVN-49 signals.
Remove data modulation from L2 P(Y)-code to mitigate
impact to high precision users.
Change L2C PRN code to a ``unique sequence'' to prevent
L2C users from including SVN 49 in their solutions.
Change SVN-49 from PRN-01 to PRN-32 to prevent updates to
WAGE users.
Use spare health code so future users could use SVN 49
despite unhealthy setting.
More information is presented in the Appendix posted in the public
docket. Implementation of each mitigation is contingent upon several
factors including cost, number of users impacted, schedule, and the
needs of the U.S. Government. If you would like to submit a public
comment concerning these proposed actions, please follow the
instructions listed above.
Issued in Washington, DC, on March 22, 2010.
Robert L. Bertini,
Deputy Administrator.
[FR Doc. 2010-6814 Filed 3-25-10; 8:45 am]
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