Federal Register Notice Seeks Comments on GPS L1 Band Interference Test Plan

UPDATE (9/10/15): A public workshop will be held in Washington, D.C., on Oct. 2 to provide an opportunity to discuss the draft test plan and address questions before the close of the public comment period.  The workshop will be held in the RTCA NBAA/Colson Room, 1150 18th St. NW, Suite 910, Washington, D.C., 20036. Click here to register for the workshop.

The U.S. Department of Transportation today published a Federal Register Notice seeking public comment on a draft test plan for the GPS Adjacent Band Compatibility Assessment effort. The plan aims to obtain interference tolerance masks for GNSS receivers in the L1 radiofrequency band (1559-1610 MHz).

The objective of the test is to collect data to determine Interference Tolerance Masks (ITM) for categories of GPS and GNSS receivers processing signals in the 1559-1610 MHz Radionavigation Satellite Service (RNSS) frequency band, as well as receivers that process Mobile Satellite Service (MSS) signals to receive differential corrections.

Demand for commercial spectrum to support broadband wireless communications — in particular, LightSquared — has led the government to consider repurposing various radio frequencies, including the satellite communications bands next to GPS. The ITMs will be used to assess the adjacent band interference power levels that can be tolerated by GNSS receivers processing desired signals in the RNSS band.

The document outlines the requirements, the overall test plan, and the associated output data needed to successfully perform this component of the GPS Adjacent Band Compatibility assessment.

The plan can be downloaded here. Deadline for comments is Oct. 9.

In December 2012, the DOT developed its GPS Adjacent Band Compatibility Assessment Plan that identifies the processes to:

• Derive adjacent-band transmitter power limit criteria for assumed new applications necessary to ensure continued operation of GPS services, and
• determine similar levels for future GPS receivers utilizing modernized GPS and interoperable GNSS signals.

The DOT has previously held three public workshops to discuss the Adjacent Band Compatibility Assessment.