Preservation of Continuity for Semi-Codeless GPS Applications

Summary:

To enable an orderly and systematic transition, the U.S. Government has established December 31, 2020 as the date by which users of semi-codeless/codeless receiving equipment are expected to transition to using GPS civil-coded signals. Based on the current launch schedule and projected budget, the December 31, 2020 transition date represents the planned availability of the second and third coded civil GPS signals being broadcast from a minimum of 24 GPS satellites. Department of Defense will reassess the transition date should significant GPS program delays arise.

For further information contact:

Mr. Raymond Swider, 703-607-1122.

Supplementary information:

The Department of Defense (DoD) provides the GPS Standard Positioning Service (SPS) for peaceful civil, commercial, and scientific uses on a continuous worldwide basis free of direct user fees. The SPS is a single-frequency GPS service which is presently limited to the coarse acquisition (C/A) code on the L1 frequency.

Access to two or more civil signals are needed to enable high accuracy civil applications. Civil users are currently employing codeless or semi-codeless techniques to gain access to encrypted GPS signals, L1 P(Y) and L2 P(Y). To facilitate expansion of civil GPS applications, the DoD has planned and begun to broadcast additional civil signals that will obviate the further need for use of codeless and semi-codeless techniques. The second coded civil GPS signal (L2C) and the third coded civil GPS signal (L5) are planned to be broadcast from 24 GPS satellites in 2016 and 2018, respectively. Full operational capability of the L2C and L5 GPS signals in combination with the existing L1 C/A signal will enable the full spectrum of dual frequency applications without using the P(Y) signals.

The U.S. Government acknowledges global use of GPS codeless and semi-codeless techniques and commits to maintaining the existing GPS L1 C/A, L1 P(Y), L2C and L2 P(Y) signal characteristics until December 31, 2020 when the second and third civil signals (L2C and L5) are planned to be broadcast from a minimum of 24 GPS satellites. After the planned transition date, the characteristics of the L1 P(Y) and L2 P(Y) signals transmitted by any or all GPS satellites broadcasting two or more civil-coded signals may change without further notice and may preclude the use of P(Y) coded signals for high accuracy applications.

The U.S. Government is committed to support civil PNT services based on GPS civil signals: L1 C/A, L2C, L5, and L1C. To this end, GPS civil signal characteristics are specified in the relevant Interface Specifications (ISs) and will be included in Performance Standards (PSs) subject to the operating descriptions contained in the Federal Radionavigation Plan (FRP). The U.S. Government has met or exceeded GPS service performance commitments in the Standard Positioning Service Performance Standard since 1993 and is committed to continually improving GPS services as codeless and semi-codeless users complete a timely transition to dual-coded civil GPS equipment.

Dated: September 16, 2008. Patricia L. Toppings,

OSD Federal Register Liaison Officer, Department of Defense.

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