Pseudorandom Noise Code Assignments

The Global Positioning System is a spread-spectrum system that employs direct-sequence spreading of the L-band carrier signals broadcast by each transmitter. The direct sequences used for the broadcast Standard Positioning Service (SPS) signals—that is, the L1 C/A, L1C, L2C, and L5 signals—are all pre-defined repeating pseudorandom noise (PRN) codes.

Many domestic and international radionavigation aids, including Satellite-Based Augmentation Systems (SBASs), seek high levels of interoperability with GPS. In the extreme, this means broadcasting SPS-like signals that include the use of PRN codes from the same PRN code families developed for GPS signals. Therefore, it has become important to assign GPS PRN codes to various GPS augmentation systems in a systematic way to prevent PRN code duplication and avoid using codes with poor properties that may interfere with receiver performance.

Signals that employ GPS PRN codes achieve an established level of code performance, including good compatibility with all other signals using GPS PRN codes. In addition, receivers can more readily generate and use all the PRN codes, thus fostering receivers that can use all signals. The resulting compatibility and interoperability are mutually beneficial to all systems using GPS PRN codes.

PRN Code Assignment Process

The GPS PRN Coordination Office (PRNCO), an entity within the Space and Missile Systems Center located in Los Angeles, CA, is responsible for managing the issuance of GPS PRN sequences.

The PRN Code Assignment Process document describes the process for requesting, assigning, and recording the GPS PRN numbers pre-selected and defined in GPS interface specifications IS-GPS-200, IS-GPS-705, and IS-GPS-800.

View document (1.2 MB PDF)

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PRN Code Assignment Tables

Updated Apr 2019

PRN codes currently assigned and available for assignment can be found in the L1 C/A, L1C L2C, and L5 PRN code assignment tables.

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Application for PRN Code Assignment

To request one or more PRN codes, an applicant must fill out a PRN Code Assignment Application.

View application (1.6 MB PDF)

Completed applications should be submitted to the GPS PRN Coordination Office (PRNCO) at smc.gp.prn@us.af.mil.

The PRNCO will review the submitted data and may request additional information. If the review results are satisfactory and sufficient PRN codes are available, the PRNCO will issue a PRN code assignment.

If there are concerns about mutual interference or other interactions, the PRNCO will contact the applicant to initiate more in-depth discussions.

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Contact Us

Applicants can contact the GPS PRN Coordination Office with any comments or questions at smc.gp.prn@us.af.mil.

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