U.S. GPS Program Update
andInternational Activities toProtect GNSS Spectrum
CSIS/UTokyo/ICG GNSS Training
Programme and Workshop
Office of Space Affairs
U.S. Department of State
14 February 2024

Agenda• Program Update• PNT Policy• GNSS Spectrum Protection, IDM andthe ICG

2GPS Constellation Status
38 Satellites • 31 Set Healthy
Baseline Constellation: 24 Satellites
Quantity

AverageAge (yrs)

OldestGPS IIR

7 (3*)

22.1

26.5

GPS IIR-M

7 (1*)

16.3

18.3

GPS IIF

11 (1*)

10.0

13.7

GPS III

6 (1*)

3.3

5.1

Satellite Block*Not set healthy

As of 01 Feb 2024

GPS Signal in Space (SIS) Performance
From 31 Dec 22 to 31 Dec 23

Average URE*

Best Day URE

Worst Day URE

48.7 cm

33.4 cm(22 Jun 23)

165.7 cm
(25 Jan 23)*All User Range Errors (UREs) are Root Mean Square values
3GPS Modernization
SV families provide L-Band broadcast to User Segment

GPS IIA/IIR• Basic GPS• Nuclear Detonation
Detection System (NDS)

GPS IIR-M• 2nd Civil Signal (L2C)• New Military Signal• Increased Anti-Jam PowerGPS IIF• 3rd Civil Signal (L5)
• Longer Life
• Better Clocks

GPS III (SV01-10)• Accuracy & Power• Increased Anti-Jam Power• Inherent Signal Integrity• 4th Civil Signal (L1C)• Longer Life
• Better Clocks

GPS IIIF (SV11-32)• Unified S-Band Telemetry,
Tracking & Commanding• Search & Rescue (SAR)
Payload• Laser Retroreflector Array• Redesigned NDS Payload

TT&C of Space Segment assets & distribution of data to user interfaces
Legacy (OCS)• Mainframe System• Command & Control• Signal Monitoring

Architecture Evolution
Plan (AEP)• Distributed Architecture• Increased Signal
Monitoring Coverage• Security• Accuracy

OCX Block 0• GPS III Launch &Checkout System
GPS III Contingency Ops (COps)• GPS III Mission on AEP

OCX Block 1/2• Fly Constellation & GPS III• Begin New Signal Control• Upgraded InformationAssurance

OCX Block 2+• Control all signals• Capability On-Ramps• GPS IIIF Evolution

Applies Space and Control Segment data for PNT applications
Continued support to an ever-growing number of applications• Annual Public Interface Control Working Group (ICWG)• Standard Positioning Service (SPS) Performance Standard Updates• Precise Positioning Service (PPS) Enhancements• Sustained commitmentto transparency• Visit GPS.gov for more info

Modernized Civil Signals• L2C (Various commercial applications)• L5 (Safety-of-life, frequency band protected)• L1C (Multi-GNSS interoperability)4GPS III••••••

SV01 Set healthy and available for use on 13 Jan 20
SV02 Set healthy and available for use on 1 Apr 20
SV03Set healthy and available for use on 1 Oct 20
SV04 Set healthy and available for use on 2 Dec 20
SV05 Set healthy and available for use on 25 May 22
SV06 Set healthy and available for use on 16 Feb 23

GPS III SVs in storage• SV07 in storage –AFL 20 May 21; TLD NET June 2024
• SV08 in storage –AFL 10 Jun 21; TLD FY25
• SV09 in storage –AFL 23 Aug 22; TLD FY25
• SV10 in Storage –AFL 8 Dec 22; TLD FY26
-AFL –Available For Launch; NET –No Earlier Than; TLD–Target Launch Date5

Next Generation Operational
Control System (OCX)• Next-generation command, control and cyber-defense
for GPSo Enhanced command and control capabilityo Modernized architectureo Robust information assurance and cyber security• Incremental Development•••

OCX Block 0: Launch and Checkout System (LCS) for GPS III
OCX Blocks 1 and 2: Controls and manages all GPS spacecraft and signals
OCX 3F: Adds support for GPS IIIF vehicle and new capabilities• Current Status•••

LCS successfully supported Launch and Checkout for GPS III SV01-SV06
OCX Block 1 completed factory integration and in Golden Dry Run forfactory qualification
Delivery/DD250 Mid-2024; Ready for Transition to Ops (RTO) Early 2025

6

Wide Area Augmentation System(WAAS)• WAAS provides high availability service toaviation users in North America• Developing Dual Frequency WAAS
•Will enable high availability of WAAS verticalservice during ionospheric disturbances• GEO Sustainability•

Currently maintaining 3 GEO constellation• WAAS Modernization Efforts•••

Dual Frequency Multi-Constellation (DFMC)
Advanced Receiver Integrity Monitoring (ARAIM)
Authentication/Resiliency••

Transition to IP based communications network
Security Upgrades
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WAAS Procedures and Avionics
Equipage• Procedures:o 4,127 Localizer Performance with Vertical
Guidance (LPV) approaches in the NAS
o 1,116 provide CAT I (200’) equivalentperformance• Equipage
o General Aviation:••

Over 131,000 equipped aircraft in the NAS
All classes of aircraft are served in all phases offlighto Airlines••

Airline integration through MMRs
Main aircraft with SBAS capability in the US A220

• Enabling technology for NextGen Programso Automatic Dependent Surveillance Broadcast(ADS-B)o Performance Based Navigation (PBN)8

U.S. Space-based PNT Policy(2020 NSP & SPD-7)
Maintain U.S. leadership in the service provision, andresponsible use of GNSS, including GPS and foreign systems•Ensure compatibility ― ability of U.S. and non-U.S. space-based PNT services to be
used separately or together without interfering with each individual service or signal•

Encourage interoperability – ability of civil U.S. and non-U.S. space-based PNT
services to be used together to provide the user better capabilities than would be achievedby relying solely on one service•

Promote transparency in civil service provision and enable market access for U.S.
industry•

Promote and support the responsible use of GPS as the pre-eminent space-based PNTservice•

Foreign space-based PNT services may be used to complement civil GPS service– Receiver manufacturers should continue to improve security, integrity, and resilience in the face ofgrowing cyber threats•Encourage foreign development of PNT services and systems based on GPS•

Support international activities to detect, mitigate, and increase resilience toharmful disruption or manipulation of GPS9

National Space-Based PNT
Organizations
DefenseTransportation

WHITE HOUSE

National Security Council / National Space Council /Office of Science and Technology Policy

State
Treasury
Justice
Interior

Agriculture

NATIONALEXECUTIVE COMMITTEEFOR SPACE-BASED PNTCommerce

Executive Steering GroupADVISORY
BOARD
Sponsor: NASA

Co-Chairs: Defense, Transportation

EnergyHomeland Security

NATIONALCOORDINATION OFFICEODNI

Host: Commerce

Joint Chiefs of Staff
NASACivil GPS Service
Interface Committee
Chair: Transportation
Deputy Chair: Coast Guard

GPS International
Working Group
Chair: StateEngineering Forum
Co-Chairs: Defense,Transportation

Ad HocWorking Groups

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Global Perspective• Global Constellations• Regional Constellations– GPS (24+3)– QZSS (4+3)– GLONASS (24+)– IRNSS/NAVIC (7)– GALILEO (24+3)– BDS/BEIDOU (27+3 IGSO + 5 GEO)

– Korea – KPS (7)• Satellite-BasedAugmentations– WAAS (3)– MSAS (2)– EGNOS (3)– GAGAN (3)– SDCM (3)– BDSBAS (3)– KASS - Korea (2)– SPAN – Australia/NZ (2) 11

International Committee on GNSS(ICG)• Pursuing a Global Navigation Satellite System-ofSystems to provide civil GNSS services that benefitusers worldwide– Promote the use of GNSS and its integration into
infrastructures, particularly in developing countries– Encourage compatibility and interoperability among
global and regional systems• U.S. priorities include spectrum protection, systeminteroperability and information dissemination• 17th Meeting held in Madrid, Spain in October 2023
• New Zealand will host the 18th Meeting in October
2024
12

What is Spectrum Protection?
• "Protection" is about keeping the spectrum 'clean'• Clean spectrum means keeping the frequencies
near to GNSS free from licenced, unlicensed andillegal transmissions that interfere with GNSS
reception, e.g.
– GNSS jammers– Uncontrolled GNSS repeater installations– Spurious emissions from radio equipment, e.g. motors– Other radio services, e.g. TV broadcasts– Malfunctioning electronic equipment
13

Clean Spectrum• Clean spectrum for GNSS minimizes signal errors andmaximizes the performance for GNSS receivers– Better and more reliable positioning and timing– Faster time to first fix– Better tracking performance in challenging environments• Keeping spectrum clean requires technical means todetect when such interference occurs• National regulators usually have the capacity to detect
strong interferers– Direction finding equipment or geolocation techniques– The ITU can also help coordinate such activities when crossborder interference occurs
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GNSS Interference• Strong interferers are relatively easy to detect• However, if weak interferers are far away fromthe detectors, they will not be seen
• The weak interfering signals are still stronger
than GNSS and will have widespread impact on
GNSS reception• To find weak interferers (e.g. 'personal' GNSSjammers) requires more specialised local
equipment or a dense detector network• The ICG has been considering this challenge
15

ICG and GNSS Spectrum
Protection• ITU is responsible for international spectrum
framework, including the protection of radio services• Actual implementation of this framework is
accomplished by national telecommunication
administrations• National telecommunication administrations workwith relevant industries and stake holders• ICG provides a forum that can facilitate andencourage the protection of GNSS spectrum by its
members and participants in a voluntary, nonbinding way
16

ICG Working Groups•

Systems, Signals and Services (Co-Chairs: U.S. & Russia)− Focus on compatibility and interoperability, encouraging development ofcomplimentary systems− Exchange information on systems and service provision plans− Includes spectrum protection and IDM•

Enhancement of GNSS Performance, New Services andCapabilities (Co-Chairs: India, European Space Agency, China)− Focus on system enhancements (multipath, integrity, interference, etc.) to meet
future needs•

Capacity Building, Education and Outreach (Chair: UN Office forOuter Space Affairs)− Focus on training/workshops, promoting scientific applications, spaceweather•

Reference Frames, Timing and Applications (Co-Chairs: IAG, IGS& FIG)
− Focus on timing, monitoring and reference station networks

17Addressing Spectrum Protectionand IDM within ICG• Establishment of Compatibility Subgroup in 2011
– Focused on compatibility issues to include spectrum
protection and IDM• Establishment of Interference Detection andMitigation Task Force in 2013
– Objectives include:1) Develop a common set of information to be reported toGNSS civil service centers
2) Establish routine communications among the (providerservice) centers3) Develop guidelines for common capabilities to beconsidered in the development of future national IDM
networks– Ten (10) IDM Workshops held since 201218

10th ICG Workshop on IDM• Workshop held on 06 December 2022
• Agenda included:– Use of GPS by U.S. Coast Guard Navigation Center – Coast Guard
Navigation Center, United States– Sharing and Crowdsourcing GNSS Data to Monitor and Protect RF
Environment – Virginia Polytechnic Institute and State University– DOT Strategic Plan for GPS/GNSS Interference Detection – Departmentof Transportation, United States– Critical Infrastructure Dependency on PNT – Department of Homeland
Security, United States– Use of ADS-B for Interference Detection - EUROCONTROL– Characterization of ADS-B Performance under GNSS Interference –Stanford University– Detecting GNSS Spoofing of ADS-B Equipped Aircraft Using INS –Illinois Institute of Technology
19

ICG Recommendations Related toIDM and Spectrum Protection
Recent Recommendations Adopted by the ICG
2014/2017

Crowdsourcing capabilities analysis for IDM

2015/2016/2017

UN regional workshops on GNSS spectrum protection and IDM

2015/2016

Campaign of Protection of RNSS operations – GNSS providers
and GNSS user community member states promote spectrumprotection

2015/2016

UN COPUOS multi-year agenda item focused on National Efforts
to protect RNSS Spectrum, and develop IDM capability

2017

Encourage national regulators to use the protection criteria inrelevant ITU-R Recommendations

2019

Produce a draft booklet on GNSS/RNSS spectrum Protection
based on material used for the ongoing spectrum seminars

2022

Incorporating Resilience into GNSS Interference Detection and20
Mitigation
20Other Related Topics Discussed
within the ICG• Adjacent Band Compatibility• Unintentional Interference– Electromagnetic emissions limits from non-licensed
transmitters• Interference Detection and Geo-Location
Capabilities• Critical Infrastructure21

For Additional Information…

www.gps.gov

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