[Federal Register Volume 82, Number 76 (Friday, April 21, 2017)]
[Pages 18736-18737]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-08080]



National Institute of Standards and Technology

Impact of Long Term Evolution Signals on Global Positioning 
System Receivers

AGENCY: National Institute of Standards and Technology, Department of 

ACTION: Notice of public meeting.


SUMMARY: The National Institute of Standards and Technology (NIST) 
announces that National Advanced Spectrum and Communications Test 
Network (NASCTN) will hold a public meeting on May 4, 2017 to inform 
the public about the NASCTN project ``Impact of Long Term Evolution 
(LTE) signals on Global Positioning System (GPS) Devices''. At this 
meeting, the public will learn about this project, as described in the 
report released to the public on February 15, 2017, available at: 
http://nvlpubs.nist.gov/nistpubs/TechnicalNotes/NIST.TN.1952.pdf. A 
summary of NASCTN's test methodology and an overview of the test 
results will be provided as well.

DATES: The meeting will be held on Thursday, May 4, 2017, from 9:00 
a.m. to 12:00 p.m. Eastern Time. To attend the meeting in person you 
must register in advance by 5:00 p.m. Eastern Time on Tuesday, May 2, 
2017. In order to access the WebEx you must register in advance by 5:00 
p.m. Eastern Time on Wednesday, May 3, 2017. For instructions on how to 
register to participate in the meeting, please see the SUPPLEMENTARY 
INFORMATION section of this notice.

ADDRESSES: The meeting will be held at MITRE Campus, Building 1, 7525 
Colshire Drive, McLean VA, 22102. Directions to the MITRE McLean Campus 
are available at: https://www.mitre.org/sites/default/files/pdf/mclean-campus-map.pdf. The meeting will also be accessible via WebEx.

FOR FURTHER INFORMATION CONTACT: For questions about this public 
meeting contact: Dr. Sheryl Genco, Communications Technology 
Laboratory, NIST by email at [email protected]; telephone (303-497-
3591) or fax (303-497-6665). Please direct media inquiries to the NIST 
Public Affairs Officer, Laura Ost by email at [email protected] or 
telephone (303-497-4880).

SUPPLEMENTARY INFORMATION: NASCTN provides a neutral forum for 
addressing spectrum-sharing challenges to accelerate the deployment of 
wireless technologies among commercial and federal users. NASCTN was 
created in 2015 and is a joint effort among NIST, the National 
Telecommunications and Information Administration, and the United 
States Department of Defense. NASCTN's mission is to provide robust 
test processes and validated measurement data necessary to develop, 
evaluate and deploy spectrum sharing technologies that can increase 
access to the spectrum by both Federal agencies and non-federal 
spectrum users. NASCTN conducts projects with private sector entities 
via Cooperative Research and Development Agreements (CRADA).\1\ NASCTN 
has completed the ``Impacts of LTE Signals on GPS Receivers'' project 
and released the NASCTN report ``LTE Impacts on GPS'' on February 15, 
2017. The report describes the project, the test methodology and the 
test results and is available at: http://nvlpubs.nist.gov/nistpubs/TechnicalNotes/NIST.TN.1952.pdf.

    \1\ A CRADA is the principal mechanism used by Federal 
laboratories to engage in collaborative efforts with non-Federal 
entities and allow the exchange of resources with private industry 
to advance technologies that can then be commercialized for the 
benefit of the public and the U.S. economy.

    The focus of this NASCTN project, proposed by Ligado Networks in 
2016 and conducted under a CRADA between NIST and Ligado Networks, was 
the development of a test methodology to: (1) Investigate the impact of 
LTE signals on GPS devices that operate in the GPS L1 frequency band; 
and (2) perform radiated radio-frequency measurements on a 
representative set of GPS devices to validate the test methodology.
    At the start of the project, NASCTN convened a panel of technical 
experts to develop a test plan with the following objectives: Develop a 
test plan that is transparent, reproducible, and well-calibrated; 
develop sound, statistically-valid data retrieval and processing 
techniques; provide a clear path from measurement setup, to data 
collection, to processed results; and provide data to inform 
discussions between different interested parties on proper measurement 
requirements. The goal

[[Page 18737]]

was to make reproducible measurements under clearly-defined test 
conditions to isolate impacts of radiated LTE signals on GPS receivers, 
and to allow others to make comparable measurements if desired. To 
accomplish this, the approach aimed to measure the response of selected 
GPS devices given well-controlled GPS and LTE power levels under fixed, 
stable thermal noise conditions, while limiting the number of other 
extraneous variables.
    In May of 2016, the NASCTN team completed the draft test plan and 
distributed it to a cross-section of GPS manufacturers, Federal 
agencies, and spectrum regulators and released it publicly for comments 
to obtain technical feedback on the proposed method. Over a two-month 
period, NASCTN received 159 comments from 10 different organizations. 
The NASCTN test team reviewed the comments and developed a revised test 
plan in July of 2016 that addressed the technical issues raised in the 
comments. The draft test plan, the revised test plan, and the 
adjudicated comments from the review process are all publicly available 
on the NASCTN Web site at: https://www.nist.gov/programs-projects/impact-lte-signals-gps-receivers.
    Over a three-month period, from August through October 2016, NASCTN 
performed the radiated measurements associated with this project at two 
facilities--a semi-anechoic chamber at National Technical Systems in 
Longmont, Colorado and at a fully-anechoic chamber at the NIST 
Broadband Interoperability Testbed facility in Boulder, Colorado, using 
the revised test plan.
    NASCTN relied on technical staff from NIST and the U.S. Army's 
Electronic Proving Grounds to perform and validate the measurements and 
collect the data. The team was multi-disciplinary, including expertise 
in GPS devices and simulation, radiated radio-frequency measurements, 
timing measurements, microwave metrology, statistical analysis and data 
    In total, NASCTN performed 1,476 hours of testing and collected 
over 19,000 data files for a variety of measurands, including carrier-
to-noise-density ratio (C/N0), 3D position error, timing 
error, number of satellites in view, time to first fix, and time to 
first reacquisition, that were collected from a number of GPS devices 
at a baseline condition (no LTE signals present) and over a large range 
of LTE signal power levels. Subsequent data processing yielded a set of 
3,859 anonymized data files (780 MB) that may be requested here: 
https://www.nist.gov/sites/default/files/documents/2017/02/15/impact_of_lte_on_gps_-_measurement_data_request_form.pdf. More 
information on this NASTCN project, including the document library and 
the archived draft test plan, the revised test plan, adjudicated 
comments, and supplemental information, is available at: https://www.nist.gov/programs-projects/impact-lte-signals-gps-receivers.
    Due to significant interest in these measurements by regulators for 
assessing LTE signals on performance of GPS devices, Federal agencies, 
and the GPS community, NASCTN is hosting a public meeting to provide an 
overview of the project, the test methodology and the test results. 
NASCTN will also answer questions on the project, the testing 
methodology and the test results. The final agenda for the public 
meeting will be posted on the NASCTN Web page, available at: https://www.nist.gov/communications-technology-laboratory-ctl/nasctn.
    Admittance Instructions: Anyone wishing to attend the NASCTN ``LTE 
Impact on GPS Devices'' public meeting must register by email to 
[email protected] no later than 5:00 p.m. Eastern Time on Tuesday, May, 2 
2017. Please provide your first and last name, email address, phone 
number, and company affiliation in the registration email.
    Seating at the public meeting may be limited, and attendance will 
be ``first-come, first-served,'' on a space-available basis.
    The public meeting will also be accessible via WebEx for those who 
are unable to participate in person. If you wish to have access to the 
WebEx, you must register in advance of the meeting by sending an email 
with your first and last name, email address, phone number, and company 
affiliation provided in the message to Dr. Sheryl Genco at 
[email protected] no later than 5:00 p.m. Eastern Time on 
Wednesday, May 3, 2017. Instructions for accessing the WebEx will be 
provided by email to individuals who register.

Kevin Kimball,
NIST Chief of Staff.
[FR Doc. 2017-08080 Filed 4-20-17; 8:45 am]