In accordance with the stated task, the NPEF focused on receivers supporting applications categorized as “General Location/Navigation” and on the first.

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Approved for Public Release; Distribution is Unlimited Approved for Public Release; Distribution is Unlimited Follow -on Assessment of LightS quared Ancillary Terres trial Component Effects o n GPS Receivers Prepared By: National Space -Based Positioning, Navigation, and Timing Systems Engineering Forum (NPEF) Approved by: Robert Erickson, Lt Col, USAF Chief Engineer GPS Directorate NPEF Co -Chair Deane Bunce GNSS SBAS Ground Segment Lead FAA NPEF Co -Chair Signature: //Signed// Signature: //Signed// Date: 19 January 2012 Date: 19 January 2012 6 January 2012

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Approved for Public Release; Distribution is Unlimited ii Approved for Public Release; Distribution is Unlimited EXECUTIVE SUMMARY The National Executive Committee (EXCOM) for Space -Based Positioning, Navigation, and Timing (PNT) tasked the National Space -Based PNT Systems Engineering Forum (NPEF) to conduct an assessment of the effects of LightSquared™s planned deployment of terrestrial broadband systems on GPS receivers .1 In accordance with the stated task, the NPEF focused on receivers supporting applications categorized as fiGeneral Location/Navigationfl and on the first phase of LightSquared™s deployment , which uses a single 10 MHz portion of spectrum (1526 Œ 1536 MHz designated as ‚10L™) for Ancillary Terrestrial Component (ATC) transmission s. fiCellularfl devices were tested by the National Telecommunications and Information Administration (NTIA) and fiCertified A viation Receivers fl were analyzed by the Federal Aviation Administration (FAA). These results will be published in a separate report. Other categories of receivers were test ed, and LightSquared handset transmissions in the band above GPS L1 from 1627.5 Œ 1656.7 MHz were si mulated as permitted by the tasking . No further testing of the 10 MHz signal in the upper band (1545.2 Œ 1555.2 MHz designated as ‚10 H™) was conducted . Results documented in NPEF Report 2, Technical Working Group (TWG) Report 3 and the Radio Technical Comm ission for Aeronautics ( RTCA ) repo rt4 demonstrate that operations in the ‚10 H™ band will significantly degrade or deny GPS for all categories of devices. No proposed mitigation filters or devices were available for this test activity . Laboratory testing was conducted at the Space and Naval Warfare Systems Command Pacific in San Diego, CA from 4 Oct ober 2011 through 14 October 2011 as a test risk reduction activity . Laboratory testing verif ied the hardware configurati on, software compatibility and testing procedures prior to anechoic chamber testing. Anechoic chamber testing was conducted at U.S. Army Research Laboratory (ARL) Electromagnetic Vulnerability Assessment Facility (EMVAF) at White Sands Missile Range, NM from 31 Oct 2011 thru 3 November 2011 , under tightly calibrated and defined RF conditions. LightSquared provided their planned antenna , filters , and signal definitions to ensure an accurate simulation o f the proposed LightSquared Long Term Evolution (LTE) ATC and handset signals. Data analysi s used NTIA provided criteria for harmful interference, a maximum -power irregular terrain propagation model, and 62 dBm effective isotropic ally -radiated power (EIRP) as directed in the EXCOM task. Testing showed that most General Navigation devices were affected by the LightSquared ‚10L™ signal. A significant percentage of general navigation devices (75%) experienced degradation in receiver carrier to noise density ratio (C/N o) of 1 dB (i.e. 25% reduction of C/N o 1 EXCOM Tasking letter to the NPEF, 12 October 2011 ) or greater at an equivalent distance of g reater than 100 meters from the LightSquared simulated tower. Although not part of the NPEF task , lab and chamber test result s 2 Assessment of LightSquared Terrestrial Broadband System Effects on GPS Receivers and GPS -dependent Applications , NPEF, 1 Jun 2011 3 The Technical Working Group Final Report into LightSquared Interference with GPS , 29 Jun 2011 4 DO-327 Assessment of the LightSquared Ancillary Terrestrial Component Radio Frequency Interference Impact on GNSS L1 Band Airborne Receiver Operations , RTCA, 3 Jun 2011

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Approved for Public Release; Distribution is Unlimited iii Approved for Public Release; Distribution is Unlimited continued to show significant degradation to high precision and timing user equipment. A significant percentage of these devices (83%) experienced degradation in receiver C/N o of 1 dB or greater at an equivalent distance of greater than 100 meters from the LightSquared simulated tower. Worst -case effects at maximum interference signal power of -15 dBm varied for each device, ranging from no significant effect to complete loss of GPS tracking. The Office of the Secretary of Defense, Chief Information Officer tasked the Massachusetts Institute of Technology (MIT) Lincoln Laboratory to perform an independent peer -review and engineering assessment of the NPEF testing methods and findings. Their independent assessment concluded, fiFindings support conclusion that Lower 10 MHz LightSquared signal results in harmful interference to majority of GPS devices tested. 5 fl Conclusion 1: Based on test results, LightSquared™s lower 10 MHz signal configuration causes harmful interference to the majority of general navigation GPS receivers tested. Test results demonstrated 69 of 92 General Navigation devices experienced harmful interference, defined as a 1 dB increase in the GPS receiver noise, with the lower 10 MHz (1526 -1536 MHz ) signal. No additional testing is required to determine that terrestrial high -power transmission in the MSS band impacts general navigation receivers. Conclusion 2: Immediate use of the Mobile Satellite Spectrum (MSS) for terrestrial service is not viable due to significant systems engineering and integration challenges . Current and previous tests have shown all categories of GPS receivers were impacted by high -power transmissions in the MSS band (1525 -1559 MHz ). The NPEF recommends denying the proposed LightSquared LTE signal plan deployment due to its corresponding GPS user impacts. At this time, no proposed mitigations addre ss interference from the ‚10H™ signal . Although ‚10L™ mitigations have been proposed, they have not been tested and verified to have no impact on GPS receiver performance and the Position, Velocity, and Timing (PVT) applications for which they are used. If and when mitigations are available , a long term transition and implementation plan would be necessary to protect existing GPS services and users. In addition, both the NPEF Report and TWG Report noted that retrofits or upgrades to military and Federal Aviation Administration (FAA) applications would take a minimum of 10 -15 years to implement. This minimum timeframe takes into account the necessary steps to design, test, manufacture, install, calibrate, and certify all affected GPS applications requirin g upgrade, retrofit, or replacement. The unbudgeted costs associated with this process will be commensurate with its duration and the total number of end -user applications affected. Conclusion 3: 5 MIT Lincoln Labs Independent Review of LightSquared Ancillary Terrestrial Components Effects on GPS Signals, 6 January 2012 ( Note: This document is For Official Use Only (FOUO)) Handset transmissions have the potential to impact Gener al Navigation GPS receivers.

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Approved for Public Release; Distribution is Unlimited iv Approved for Public Release; Distribution is Unlimited Test data show some GPS receivers were suscep tible to receiving interference from LightSquared handset transmissions in the 1627.5 Π1656.7 MHz band. Handset test data collected are sufficient, but additional analysis is requ ired. This analysis would include the characterization of actual LightSquared handsets and aggregate radio frequency interference (RFI) modeling of multiple handset users in a given region.

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Approved for Public Release; Distribution is Unlimited v Approved for Public Release; Distribution is Unlimited TABLE OF CONTENTS 1. OVERVIEW .. 11.1 INTRODUCTION 11.2 FOLLOW -ON TEST SCOPE 21.3 INDE PENDENT TEST ASSESSM ENT 32. SPAWAR LABORATORY TE ST . 32.1 SPAWAR FACILITY . 42.2 LABORATORY TEST LIMITATIONS . 42.3 LABORATORY TEST SET -UP . 42.4 LABORATORY TEST EXEC UTION . 53. EMVAF ANECHOIC CHAMB ER TEST .. 53.1 EMVAF FACILITY 53.2 ANECHO IC CHAMBER TEST SETU P AND CALIBRATION 63.2.1 GPS Simulation . 63.2.2 LTE Simulation . 73.2.3 Physic al Set -Up 93.2.4 Calibration and Chamber Mapping 103.3 ANECHOIC CHAMBER TES T LIMITATIONS .. 133.4 ANECHOIC CHAMBER TES T EXECUTION .. 133.4.1 Timing and Control .. 133.4.2 Test Events and Schedule . 143.4.3 Test Event Description .. 154. DATA ANALYSIS . 224.1 DATA ANONYMITY PROCE SS 224.2 ANALYSIS ASSUMPTIONS AND CONDITIONS 224.2.1 Propagation Models . 224.2.2 Receiver Antenna Position .. 254.2.3 LightSquared Authorized Power .. 254.2.4 Noise Environment .. 254.2.5 Antenna -Receiver Configuration . 264.2.6 General . 264.3 DATA ANALYSIS METHODOLOGY .. 264.3.1 Data Collection Process . 264.3.2 Analysis Tools and Techniques 274.3.3 Analysis Process 275. SUMMARY OF RESULTS A ND CONCLUSIONS . 295.1 ANECHOIC CHAMBER TES T RESULTS .. 295.1.1 General Navigation Results . 29

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Approved for Public Release; Distribution is Unlimited vi Approved for Public Release; Distribution is Unlimited 5.1.2 Other Devices .. 325.2 CONCLUSI ONS . 35APPENDIX A. LIST OF ACRONYMS AND CONSTANTS . A-1APPENDIX B. TEST EVENTS .. B-1B.1 LABORATORY TEST EV ENTS . B-1B.2 ANECHOIC CHAMBER TEST EVENTS . B-4APPENDIX C. RECEIVERS UNDER TEST . C-1APPENDIX D. DETAILED RESULTS .. D-1D.0 PLOTS FOR TEST E VENT 0 AND TEST EVEN T 9 D-1D.1 PLOTS FOR TEST E VENT 1 AND TEST EVEN T 10 . D-1D.2 PLOTS FOR TEST E VENTS 3, 4 AND TEST EVENTS 12,13 .. D-1D.3 PLOTS FOR TEST E VENTS 5, 6 AND TEST EVENTS 14, 15 . D-1D.4 PLOTS FOR TEST E VENTS 7, 8 AND TEST EVENTS 16, 17 . D-1APPENDIX E. SET -UP AND CALIBRATION . E-1E.1 EMVAF CHAMBER MA PPING .. E-1E.2 GPS SIMULATION CALIB RATION . E-26APPENDIX F. PROPAGATION MODELS . F-1F.1 INTRODUCTION .. F-1F.2 FREE SPACE PROPAGATION (62 DBM EIRP) .. F-1F.3 IRREGULAR TERRAI N MODEL .. F-1APPENDIX G. LIGHTSQUARED SIGNAL SIMULATION G-1APPENDIX H. AGILENT SETTINGS FOR LTE SIMULATION H-1APPENDIX I. ALMANAC DATA . I-1APPENDIX J. IONOSPHERE AND TROPO SPHERE MODELS . J-1APPENDIX K. REFERENCES . K-1

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Approved for Public Release; Distribution is Unlimited 1 Approved for Public Release; Distri bution is Unlimited 1. OVERVIEW 1.1 INTRODUCTION The LightSquared Ancillary Terrestrial Component (ATC ) Follow -on Test was designed to assess the impacts to military and commercial G lobal Positioning System (GPS) User Equipment (UE), in the presence of LightSquared ATC deployment of a 10 MHz Long Term Evolution (LTE) Signal at 1526 -1536 MHz and 62 dBm effec tive isotropic ally -radiated power (EIRP). This test also assessed the impact due to LightSquared handset transmissions at 1627.5 -1656.7 MHz . These test conditions were selected pursuant to the Space -Based Positioning, Navigation and Timing (PNT) Executiv e Steering Group Tasking Statement to the National PNT Engineering Forum (NPEF ),6 dated 12 October 2011 . As the U.S. government lead for the Global Positioning System, the National Executive Committee for Space -Based Positioning, Navigation, and Timing (EXCOM) tasked the NPEF to conduct a follow -on assessment of the effects on GPS UE based upon LightSquared ™s planned deploymen t of ATC transmitters . The NPEF, co -chaired by DoD and DOT, assumed overall test planning, conduct, and reporting responsibilities. The Anechoic Chamber test plan 7 was coordinated with National Telecommunications and Information Administration ( NTIA ) and LightSquared prior to test execution in compliance with the tasker . Originally LightSquar ed proposed to deploy capability in three phase s (Phase 0, Phase 1, and Phase 2). Phase 0 was one 5 MHz bandwidth signal from 1550.2 Œ 1555.2 MHz (designated ‚5H™), Phase 1 was two 5 MHz bandwidth signals from 1526. 3 Œ 1531.3 MHz and 1550.2 -1555.2 MHz (designated ‚Dual 5™), and Phase 2 was two 10 MHz bandwidth signals from 1526 -1536 MHz and 1545.2 Œ 1555.2 MHz (designated ‚Dual 10™). After results were released from both the NPEF and Technical Working Group ( TWG ) reports, LightSquared pr oposed a new initial deployment approach with only one 10 MHz signal from 1526 -1536 MHz (designated ‚10L™). LightSqua red has proposed deploying the upper band at a later date . The LightSquared proposal to confine operations to the ‚10L™ signal (1526 -1536 MHz ) of the Mobile -Satellite Services (MSS) frequency band was the focus of this testing. The LightSquared ATC Follow -on Test characterized the effects of the ‚10L™ LightSquared signal on a variety of representative GPS receivers used by federal and commercial GPS -dependent users, systems, and networks. Additionally, prior testing did not fully address the potential impact on GPS receivers due to LightSquared handset transmissions at 1627.5 -1656.7 MHz . LightSquared provided infor mation that handset transmission will occur in two 10 MHz blocks with center frequencies of 1651.7 MHz and 1632.5 MHz . These signals were also simulated to test the impact on GPS receivers . 6 EXCOM Tasking letter to the NPEF, 12 October 2011 7 Test Plan for the LightSqua red Ancillary Terrestrial Component Effects on GPS Receivers: Follow -on Test (Anechoic Chamber) , NPEF, 23 Oct 2011

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Approved for Public Release; Distribution is Unlimited 2 Approved for Public Release; Distri bution is Unlimited As a test risk reduction effort, l aboratory testing was conducted at the Central Engineering Agency (CEA) laboratory at Space and Naval Warfare Systems Command , Pacific ( SPAWAR -Pacific) in Sa n Diego, CA from 4 Oct 2011 through 14 October 2011. The subsequent Anechoic Chamber testing was c onducted at Army Research Lab oratory Electromagnetic Vulnerability . Assessment Facility (EMVAF) at White Sands Missile Range (WSMR) , NM from 31 Oct 2011 through 3 Nov 2011. 1.2 FOLLOW -ON TEST SCOPE The test scope, as defined in the NPEF Tasking Statement ,8 was focused on receivers supporting applications that fit into the fiGeneral Location/Navigationfl category as defined by the TWG report. 9 Further, the scope was also focused on only the first phase of LightSquared deployment (10L) with a maximum base stati on EIRP of 32 dBW (62 dBm) per sector. The follow -on test effort include d participants from across the U.S. Federal government and commercial entities inc luding LightSquared. Test participants are listed below: Department of Commerce o National Weather Ser vice o National Oceanic Atmospheric Agency (NOAA) Coast Survey o NOAA National Center for Atmospheric Research (NCAR) Department of Interior РBureau of Land Management (BLM) Department of Transportation o Federal Aviation Administration (FAA) o Federal Highway Administration (FHWA) o Federal Railroad Administration (FRA) Department of Defense o United States Navy ΠSPAWAR -Pacific o United States Navy ΠNaval Research Lab o United States Naval Observatory o United States Air Force Π746th Test Squadron o United States Army ΠArmy Research Lab o National Geospatial -Intelligence Agency Department of Homeland Security РUnited States Coast Guard United States Department of Agriculture Department of State Commercial Participants o Broadcom o Garmin o Hemisphere GPS o John Deere o LightSquared o OnStar o Trimble 8 EXCOM Tasking letter to the NPEF, 12 October 2011 9 The Technical Working Group Final Report into LightSquared Interference with GPS , 29 Jun 2011

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Approved for Public Release; Distribution is Unlimited 3 Approved for Public Release; Distri bution is Unlimited Due to the time constraints for test completion , the NPEF did not limit federal or commercial participants requested receivers from participating in the testing. In addition, as allowed by the tasking statement, other receivers were teste d (at each participating organization™s discretion ) as well as the effect of simulated LightSquared handsets . The follow -on cell phone testing was conducted by NTIA and LightSquared in a separate event. 1.3 INDEPENDENT TEST ASS ESSMENT Idaho National Labs (INL) was identified and tasked to provide an independent assessment of the test plan, setup and execution. Specific taskings included: Review the testing requirements established in the NPEF Tasking Statement and compare them to the test plan. Review the test set -up and observe the test execution and data collection. Additionally INL should ensure that the test plan and test execution accomplish the objectives and meet the requirements established by the tasking letters. Overall the INL team had no majo r discrepancies to report. 10 Testing was conducted as planned. The Office of the Secretary of Defense, Chief Information Officer tasked the Massachusetts Institute of Technology (MIT) Lincoln Laboratory to perform an independent peer -review and engineerin g assessment of the NPEF testing methods and findings. Their independent assessment concluded, fiFindings support conclusion that Lower 10 MHz LightSquared signal results in harmful interference to majority of GPS devices tested. 11 fl 2. SPAWAR LABORATORY TE ST Laboratory testing was an essential step in designing and executing the Anechoic Chamber test plan. Laboratory testing provided the opportunity to plan and execute: Test events Timing of test events Optimization of test sequences Synchronization of test equipment The test team made adjustments to the lab test configuration to ensure optimum test sequences during the chamber testing. Lessons learned ensured all GPS scenario times moved forward in time (instead of resetting the GPS time each day). These l aboratory activities greatly improved the efficiency, value and execution of Anechoic Chamber testing. 10 Idaho National Laboratory Independent Assessment of the Follow -on Test of LightSquared Ancillary Terrestrial Component Effects on GPS Recievers , 5 December 2011 (Note: This document is For Official Use Only (FOUO)) 11 MIT Lincoln Labs Independent Review of LightSquared Ancillary Terrestrial Components Effects on GPS Signals, 6 January 2012 ( Note: This document is For Official Use Only (FOUO))

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Approved for Public Release; Distribution is Unlimited 4 Approved for Public Release; Distri bution is Unlimited 2.1 SPAWAR FACILITY SPAWAR Central Engineering Activity (CEA) Laboratory provided capable and experienced testing of GPS Military and Civilian User Equipment. The CEA facility included: Port able anechoic chambers Inertial rate t able s Complete inertial measurements unit (IMU) modeling Complete inertial navigation systems (INS) modeling Port able environmental chambers Multiple GPS simulators (Interstat e Electronics Corporation (IEC), Advanced Global Navigation Simulator (AGNS), NAVLabs, CAST) Multiple Cesium and Rubidium clocks Multiple test stations Multiple jammer configurations Mobile engineering all -inclusive test (MEAT) rack The CEA laboratory is l ocated at the Space and Naval Warfare System Center, Pacific in San Diego, CA. In addition to special testing (such as LightSquared), the CEA routinely supports GPS receiver testing for the GPS Directorate and US Navy. 2.2 LABORATORY TEST LIMI TATIONS Laborat ory testing provided a complete characterization of a GPS receiver excluding the antenna system. Port able anechoic chambers provided only for a qualitative analysis of the GPS receiver with its antenna system. The laboratory shares the same test limitation s as the Chamber (see Section 3.3 ). Additional laboratory testing limitations include: Lack of complete characterization of the GPS receivers antenna system using the LightSquared transmit antennas or equivalent LightSquared handset generation did not use LightSquared handset filters due to non -availability 2.3 LABORATORY TEST SET -UP A block diagram of the SPAWAR laboratory test set -up is shown in Figure 1. During the laboratory test, the LightSquared signal was generated using commercially available equipment with LightSquared -provided filters. Agilent signal generators (Model N5182A with LTE software version 10) were used to generate the LTE signals. The signals were amplified using a 40 dB gain mini -circuits amplifier, then filtered through the LightSquared -provided filter. Figure 3 is a block diagram of the ATC base station signal simulation setup.

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