[Federal Register Volume 73, Number 96 (Friday, May 16, 2008)]
[Notices]
[Pages 28433-28435]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-11148]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[Docket No.: 080506632-8633-01]
Codeless and Semi-Codeless Access to the Global Positioning
System
AGENCY: Office of Space Commercialization, National Oceanic and
Atmospheric Administration, Department of Commerce.
ACTION: Notice and request for comments.
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SUMMARY: The Office of Space Commercialization seeks comments on a plan
to transition the installed base of codeless and semi-codeless Global
Positioning System (GPS) user equipment to next-generation equipment
utilizing the modernized civil GPS signals known as L2C and L5. The
plan was developed under the auspices of the National Executive
Committee for Space-Based Positioning, Navigation, and Timing (PNT).
Under the plan, the Department of Defense, as the operator of GPS, will
continue
[[Page 28434]]
enabling codeless/semi-codeless GPS access until December 31, 2020, by
which time the L2C and L5 signals will be available on 24 or more
modernized GPS satellites. Users should re-equip to use the modernized
signals, since codeless/semi-codeless GPS access cannot be assured
beyond 2020.
DATES: Submit comments on or before June 16, 2008.
ADDRESSES: You may submit comments by any of the following methods: E-
mail: [email protected]. Fax: (202) 482-4429 (Attn.: Jason Kim). Mail/
Courier: Jason Kim, Office of Space Commercialization, U.S. Department
of Commerce, 6818 Herbert C. Hoover Building, 14th St. & Pennsylvania
Ave., NW., Washington, DC 20230. Due to ongoing delays in mail
delivery, respondents are encouraged to submit comments by mail early,
or to transmit them electronically. Office hours for courier delivery
are 9 a.m. to 5 p.m., Monday through Friday, except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Jason Kim, Senior Policy Analyst,
Office of Space Commercialization, U.S. Department of Commerce, (202)
482-5827.
SUPPLEMENTARY INFORMATION: The Global Positioning System (GPS) is a
U.S. Government constellation of 24 or more satellites providing
precise positioning, navigation, and timing (PNT) capabilities, free of
direct user fees, on a continuous, worldwide basis. GPS currently
transmits PNT information on two radio frequencies known as L1 (1575
MHz) and L2 (1227 MHz). In the future, GPS will also transmit
information on a third frequency known as L5 (1176 MHz).
GPS transmits encrypted signals known as Y-code or P(Y)-code at the
L1 and L2 frequencies. Y-code is intended primarily for U.S. and allied
military use, but the civilian community has developed techniques that
exploit Y-code at L1 and L2 to achieve significant accuracy gains. Such
techniques, collectively known as codeless or semi-codeless GPS access,
have been integrated into a range of GPS receivers sold commercially
around the world.
The Y-code signal was never designed or intended for codeless/semi-
codeless access. However, the Department of Defense, as the GPS
operator, has historically supported codeless and semi-codeless users
by documenting a time-limited commitment to the Y-code signal in the
GPS Standard Positioning Service (SPS) Performance Standard and the
Federal Radionavigation Plan. For example, the current GPS SPS
Performance Standard (dated October 2001) includes the statement that,
``Until such time as a second coded civil GPS signal is operational,
the U.S. Government has agreed to not intentionally reduce the current
received minimum Radio Frequency signal strength of the P(Y)-coded
signal on the L2 link, as specified in ICD-GPS-200C or to intentionally
alter the P(Y)-coded signal on the L2 link.'' As a result,
manufacturers have continued to develop codeless/semi-codeless GPS
equipment.
The U.S. Government acknowledges the global use of GPS codeless and
semi-codeless techniques and plans to maintain the existing GPS L1 Y-
code and L2 Y-code signal characteristics until such time that an
alternative capability exists to replace it. Since 1999, the Department
of Defense has worked closely with the civilian agencies on the
National Executive Committee for Space-Based PNT (and its predecessor,
the Interagency GPS Executive Board) to add new capabilities to GPS
that supplant the need for codeless/semi-codeless access. In 2005, the
U.S. Air Force began launching modernized GPS satellites featuring a
new civil signal at L2 called L2C. L2C is designed to work in
combination with the legacy civil signal (called C/A) at L1 to enable
high accuracy without codeless/semi-codeless techniques. In 2009, the
Air Force will begin adding a third civil signal called L5 to all new
GPS satellites. L5 will also work in combination with L1 C/A and/or L2C
to enable high accuracy without codeless/semi-codeless techniques.
The National Executive Committee for Space-Based PNT seeks to
encourage the development and adoption of next-generation GPS receivers
that achieve high accuracy via use of L2C and/or L5 instead of
codeless/semi-codeless techniques. To facilitate business decisions and
stable planning for equipment developers and end users, the National
Executive Committee intends to set a fixed target date for the
equipment transition.
The National Executive Committee proposes December 31, 2020, as the
target date for transitioning the installed base of codeless/semi-
codeless GPS equipment to next-generation capabilities utilizing the
modernized civil GPS signals. This date is based upon the current
launch schedule for the GPS program, which will have 24 GPS satellites
transmitting the L2C signal to users by 2016, and 24 GPS satellites
transmitting L5 by 2018. The date is also based on preliminary
discussions the Office of Space Commercialization has held with GPS
equipment manufacturers. The manufacturers indicated that a transition
period of approximately ten years should be sufficient to allow the
installed base of codeless/semi-codeless GPS users to re-equip with
next-generation receivers as part of their normal equipment
amortization, obsolescence, and upgrade cycle.
Should there be unforeseen delays in the GPS modernization program,
the National Executive Committee will reassess the target date for the
transition.
After the transition date, the characteristics of the Y-code
signals transmitted by modernized GPS satellites may change without
further notice and may preclude codeless/semi-codeless use of the Y-
code signals. However, for those legacy satellites that have no
modernized capabilities, codeless/semi-codeless access to Y-code at L1
and L2 will continue until those satellites are decommissioned.
The Office of Space Commercialization encourages the GPS user
community and manufacturing industry to provide feedback on this
proposed plan within the next 30 days. Both domestic and international
comments are welcome due to the global nature of GPS use. The National
Executive Committee will take the public comments into account as it
prepares a final announcement on the date for the codeless/semi-
codeless GPS transition. The Department of Defense will publish the
final announcement in the Federal Register.
Concurrent with the final transition plan announcement, the
Department of Defense intends to release an update to the SPS
Performance Standard that no longer includes a reference to Y-code
stability in support of codeless/semi-codeless access. The final
announcement would serve to document the government's continued
commitment to protect codeless/semi-codeless GPS access through the end
of the transition period. Specifically, the final announcement would
commit the Department of Defense to maintaining the existing GPS L1 Y-
code and L2 Y-code signal characteristics until December 31, 2020. The
announcement would also state that should there be unforeseen delays in
the GPS modernization program, the date will be reassessed.
Instructions for the submission of comments.
Page Limit--Submissions should be limited to a maximum length of
four pages.
Identification and Cover Sheet--Mark each page of the submission
with the docket number, submitter's name (and
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organization, if applicable), date of submission, and contact
information (if the submitter chooses to provide it).
Additional information--The Office of Space Commercialization
encourages interested persons who wish to comment to do so at the
earliest possible time. The Office will consider all comments received
before the close of the comment period on June 16, 2008. Consideration
of comments received after the end of the comment period cannot be
assured. The Office will not accept comments accompanied by a request
that part or all of the material be treated confidentially because of
its business proprietary nature or for any other reason. All comments
submitted in response to this notice will be a matter of public record
and will be available for public inspection and copying at http://www.space.commerce.gov.
Authority: NSPD-39; 10 USC Sec 2281(b)(5).
Dated: May 14, 2008.
Ed Morris,
Director, Office of Space Commercialization.
[FR Doc. E8-11148 Filed 5-15-08; 8:45 am]
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