Aviation Spectrum Re

Ex PARTE PRESENTATION NOTIFICATION LETTER submitted by Aviation Spectrum Resources Inc

Aviation Spectrum Resources, Inc. Written Ex Parte

2018-09-24

This document pretains to SES-AMD-20180531-00856 for Amended Filing on a Satellite Earth Station filing.

IBFS_SESAMD2018053100856_1538000

KELLEY DRYE & WARREN LLP A LIMITED LIABILITY PARTNERSHIP WASHINGTON HARBOUR, SUITE 400 FACSIMILE 3050 K STREET, NW (202) 342-6451 NEW YORK,NY www.kelleydrye.com LOS ANGELES,CA WASHINGTON, DC 20007 HOUSTON,TX C H I CAG O , I L (202) 342-8400 EDWARD A. YORKGITIS, JR PARSIPPANY, NJ STAMFORD. CT DIRECT LINE:(202) 342-6640 AFFILIATE OFFICE EMAIL:oyorkoilis@kelleydrye com MUMBAI, INDIA September 24, 2018 Ms. Marlene H. Dortch vw ECFS Secretary Federal Communications Commission 445 12th Street, S.W. Washington, D.C. 20554 Re; Written Ex Parte Presentation of Aviation Spectrum Resources, Inc.: IB Docket Nos. II-I09,12-340; IBFS File Nos. SES-MOD-20151231-00981, SAT-MOD-2015123I-00090, SAT-MOD-20151231-00091, SES-AMD- 20180531-00856 Dear Ms. Dortch: Aviation Spectrum Resources, Inc. (“ASRI”), by its attorney, hereby submits for inclusion in the record in the above-referenced matters the attached August 10, 2018, Letter of the Positioning, Navigation and Timing (“PNT”) Advisory Board (“PNTAB”)' containing its recommendation to the PNT Executive Committee (“EXCOM”) regarding the Ligado License Modification Application Amendment of May 31,2018 submitted in the above-referenced application IBFS Files (the “Ligado proposal”).^ ' The PNTAB provides independent advice to the U.S. government on GPS-related policy, planning, program management, and funding profiles in relation to the current state of national and international satellite navigation services. The PNTAB consists of GPS experts from outside the U.S. government, with 25 members representing U.S. industry, academia, and international organizations. See https://www.gD$.uov/uovernance/advisory/ 2 Letter of Bradford W. Parkinson, U‘ Vice Chair, PNTAB, to Patrick M. Shanahan, Deputy Sec’y of Defense and Jeffrey A. Rosen, Deputy Sec’y of Transportation, dated Aug. 10, 2018 (the “PNTAB Letter”), appended hereto. The PNTAB Letter can be found online at httns://rntfnd.orti/20]8/08/10/ijnt-board-letter-on-liEado-nublished/ NG-2TSFKRLD 4835-6304-5236vl

KELLEY DRYE & WARREN LLP Ms. Marlene H. Dorteh September 24, 2018 Page 2 The PNTAB Letter stated that to assess potential interferenee from Ligado to GPS devices “the only tests that met the PNTAB criteria were the DOT’S Adjacent Band Compatihility [tests].The PNTAB Letter goes on to state that “We strongly support ‘no more than 25% (1 dB) noise degradation’, which is the long accepted international standard for evaluating interference to GPS and similar systems.” PNTAB Letter at 1."^ In reviewing other testing available, the PNTAB Letter states that the “[pjroof of ‘assured protection’ ascribed to Ligado- sponsored tests ... were found inadequate & incomplete by independent review board.”^ The PNTAB declares further that Ligado’s “suggest[ions] that the major GPS manufacturers have agreed with their position” are “clearly untrue.” PNTAB Letter at 1. The PNTAB Letter quantifies the impact from lOW Ligado transmitters on general aviation and helicopter (“GAV”) GPS receivers (of the non-certified category). PNTAB explains that the bounding degradation radius for GAV receivers from a single Ligado tower at low would be 1040 meters. Id., at 2. The PNTAB Letter also states that the minimum separation between Ligado 10 W transmitters to protect GAV receivers at maximum 10% degradation - meaning “avoiding degradation over at least 90% of the region near Ligado transmitters” - would be almost 6.3 km. Id. The PNTAB Letter notes that even more restrictive separation criteria may be needed “if Ligado is to operate without unduly interfering in real world conditions.” Id. The PNTAB also addressed the economic arguments that have been submitted into the record, concluding that the “risk is far too great, and far too many questions remain, for Ligado’s proposal to be approved.” Id. at 3. The PNTAB Letter observes that, “[wjhile there are many broadband alternatives (Ligado would be a very small percentage of this national asset), [a]ny impairment to current and future uses [of GPS] is clearly contrary to the national interest.” Id. The PNTAB adds that Ligado “[c]ontinues to totally ignore effects on new GPS signals (LIC) and complementary GNSS systems (e.g. Galileo)'^ Id. (emphasis added). Notably, a recent PNT study referenced in the PNTAB Letter ascribed that for High Performance GPS receivers alone, there are over $31 Billion in annua! benefits.^ ^ PNTAB Letter, Attachment, at 5, slide 10 (rating “Ligado Sponsored” and other tests for “compliance with PNTAB criteria”). See also U.S. Department of Transportation, Global Positioning System (GPS) Adjacent Band Compatibility Assessment (April 2018). The PNTAB “explicitly reject[s] Ligado’s critique of this {i.e., the 1 dB] standard.” Id. 5 Id., Attachment, at 2, slide 3 (Summary of the latest Ligado Proposal). ^ Id. at 2, citing The Economic Value of GPS: Preliminary Assessment, June 11, 2015, found at https://www.tms.ttov/aovernance/advisorv/meetinas/2015-Q6/levesoivpdf NG-2TSFKRLD 4835-6304-5236vl

KELLEY DRYE & WARREN LLP Ms. Marlene H. Dorteh September 24, 2018 Page 3 The PNTAB Letter concludes with the clear statement that “the technical consensus of the PNTAB” leads the PNTAB to “strongly recommend [EXCOM’s] opposition to the Ligado proposal. ” ^ leaving little doubt as to the collective views of the independent OPS experts formally recognized and appointed by the US government. This letter is being filed with the Secretary’s office as required by Section 1.1206 of the Commission’s Rules, 47 C.F.R. § 1.1206. Respectfully submitted. Edward A Yorkgitis, Jr. Attorney for Aviation Sp< ^um Resources, Inc. Attachment cc: Rachael Bender, Advisor to Chairman Pai Erin McGrath, Advisor to Commissioner O’Rielly Umair Javed, Advisor to Commissioner Jessica Rosenworcel Will Adams, Advisor to Commissioner Carr Julius Knapp, Office of Engineering and Technology Ronald Repasi, Office of Engineering and Technology Paul Murray, Office of Engineering and Technology Michael Ha, Office of Engineering and Technology Charles Mathias, Wireless Telecommunications Bureau Jose Albuquerque, International Bureau Karl Kensinger, International Bureau Robert Nelson, International Bureau ’ PNTAB Letter at 3 (bold emphasis in original). The Chair and certain members of the PNTAB recused themselves from the PNTAB Letter “to avoid any appearance of a conflict of interest.” Id. NG-2TSFKRLD 4835-6304-5236vl

ATTACHMENT August 10, 2018, Letter of the Positioning, Navigation and Timing Advisory Board containing its recommendation to the PNT Executive Committee regarding the Ligado License Modification Application Amendment of May 31, 2018 NG-2TSFKRLD 4835-6304-5236vl

August 10, 2018 Honorable Patrick M. Shanahan, Deputy Secretary of Defense Honorable Jeffrey A. Rosen, Deputy Secretary of Transportation Co-Chairs, National Executive Committee for Space-based Positioning, Navigation and Timing Herbert C. Hoover Building, Room 2518 1401 Constitution Ave., NW Washington, D.C. 20230 Subject: PNT Advisory Board (PNTAB) Recommendation to PNT Executive Committee (EXCOM) Regarding Latest Ligado Proposal Dear EXCOM Chairs and Members, On the 31st of May 2018, Ligado Networks amended its Federal Communications Commission (FCC) license modification application. They have proposed reducing initial transmitter power to ~ 10 watts and abandoning use of the band closest to Global Positioning System (GPS) frequencies. Unfortunately, they have not specified transmitter spacing nor do they propose a feasible scheme for monitoring their interference levels, expecting the GPS user to contact them instead. We recognize the need for efficient spectrum management. At the same time, we believe it is imperative that we follow the PNT EXCOM stricture to not adversely affect current and future GPS uses. To pursue this purpose, we strongly support “no more than 25% (1 dB) noise degradation”, which is the long accepted international standard for evaluating interference to GPS and similar systems. Ligado has never agreed that this international standard applies to their proposed use of the adjacent band. They have suggested that the major GPS manufacturers have agreed with their position. This is clearly untrue. Trimble, Deere, and Garmin have all recently responded with filings that specifically support use of the 25% degradation standard 1. They explicitly reject Ligado’s critique of this standard and Ligado’s attempts to use other, unconventional criteria that would not protect all GPS uses. We believe GPS users should be protected everywhere. But even if the nation decided to apply the 1 dB criterion to only 90% of the area surrounding Ligado transmitters, their new proposal must be rejected. Their revised ~ 10 watt 1 Comments filed on Ligado’s May 31, 2018 Amended License Modification Application in Docket 11-109: Comments of Garmin International, Inc. July 9, 2018: “In its Amendment, Ligado again criticizes the use of a standard metric-a 1 dB decrease in a GPS device’s carrier-to-noise-density ratio (“C/No”) (the “1 dB Standard”) – as a threshold determinant of harmful interference to a GPS receiver’s operation.” “As Garmin has documented extensively in the record, the 1 dB Standard is the long-established and appropriate determinant of harmful interference to GPS and other Radio Navigation Satellite Service (RNSS) receivers” Comments of Trimble Inc. July 9, 2018:“To the extent that, in evaluating the Modification Applications, the Commission addresses the standard for determining the potential for harmful interference to Global Positioning System (“GPS”) and Global Navigation Satellite System (“GNSS”) devices and applications, it should dismiss Ligado’s calls for the rejection of the long- established interference protection criterion for GPS/GNSS receivers of a 1 dB decrease in the Carrier-to-Noise Power Density Ratio (“C/No”) and the proposed alternative use of key performance indicators (“KPIs”).” Comments of Deere and Company, July 9, 2018: “Deere nonetheless advises that its position with respect to Ligado’s Amended Modification Applications must not be interpreted as acquiescence in or, in any way agreement with, Ligado’s continued efforts to depart from long-accepted practice and establish a new metric for determining potential harm to GPS and other GNSS systems based on Key Performance Indicators (“KPIs”). Deere does not agree with this approach and reaffirms its staunch support for application of a one (1) dB decrease in Carrier-to-Noise Power Density (“C/N0”) (the “1 dB Standard”) as the appropriate metric for determining whether a GPS receiver has experienced harmful interference.”

maximum Effective Isotropic Radiated Power (EIRP) proposal far exceeds the power level that can be tolerated by the GPS-user community at the previous spacing of ~400 meters by a factor of over 2,500. We believe avoiding degradation over at least 90% of the region near Ligado transmitters is the absolute minimum protection for GPS receivers in each class. This would be a hypothetical 90% Protection Evaluation. This is not an endorsement of this level since of course, all users would prefer 100% protection. The Department of Transportation (DOT) Adjacent Band Compatibility (ABC) study is the only validated test 2 to verify degradation at various received power levels. Those results inform that to insure degradation not exceed 10% of the Region (90% Protection) for High Performance receivers, either: • Ligado maximum power can be no more than .0036 watts at the 400-meter spacing they had earlier planned. Tolerable power would be 3/10ths of 1% of their proposed ~ 10 watts. (see enclosure) Or • The closest spacing of Ligado transmitters is 20,000 meters 3 (over 12 miles) for their proposed ~ 10 watt power level (see table below for other receiver classes) While the GPS high performance receivers are the most sensitive to interference, they are also the most valuable. The most recent PNT EXCOM study ascribed over $31 Billion in annual benefits to this class alone 4. As restrictive as these criteria are, they may need to be even more so if Ligado is to operate without unduly interfering in real-world conditions. When performing the calculations to arrive at these criteria, we did not consider the following points that would impose greater restrictions: • The aggregate noise created by transmissions from multiple towers • Reflections from the ground and buildings which can increase interference by a factor of 10 or more • The impact on PNT uses of newer GNSS signals, such as those from Europe’s Galileo GNSS • Impacts on Military Users 2 National PNT Systems Engineering Forum (NPEF) GAP Analysis, March 5, 2018 3 Separation to insure degradation not exceed 10% for other classes of receivers is in the following Chart (see enclosure for explanation of ABC data that gives the Bounding Degradation Radius) 4 The Economic Value of GPS: Preliminary Assessment, June 11, 2015. https://www.gps.gov/governance/advisory/meetings/2015-06/leveson.pdf 2

In addition, it is not reasonable that one interference source, Ligado, be allowed to use up the whole interference budget for GPS. We believe there are further serious concerns about the impact of Ligado’s proposed operations on special, and scientific users of GPS that should be fully explored, such as: • Unmanned Aerial Vehicles (UAVs) • Weather data and forecast • Space-based receivers This risk is far too great, and far too many questions remain, for Ligado’s proposal to be approved. While there are many broadband alternatives (Ligado would be a very small percentage of this national asset), there is only one GPS. Any impairment to current and future uses is clearly contrary to the national interest. Therefore, implementation of their recently proposed ~ 10 watt operating scheme will create totally unacceptable interference for a great number of GPS users in the United States. In fact, despite power limits in their current amended application, it is probable they could still be allowed to increase this power over time. This would be even more destructive to GPS users. This is the technical consensus of the PNTAB. We strongly recommend your opposition to the Ligado proposal. Data from the DOT’s ABC Study was used to reach these conclusions. This study, the third formal examination of this issue by the PNT EXCOM, met all scientific criteria for a credible national evaluation. Calculations and graphs used to support these results are provided in the attachment. Sincerely, ___________________________________________________ Bradford W. Parkinson, 1st Vice-Chair, on behalf of the PNTAB (PNTAB Chair and some members recused to avoid any appearance of a conflict of interest) Enclosure: Supporting calculations and graphs cc: − PNT EXCOM Departments and Agencies − Hon. Jim Bridenstine, NASA Administrator − Dr. Scott Pace, Executive Secretary, National Space Council (NSpC) − Hon. David Redl, Assistant Secretary for Communications and Information and Administrator, National Telecommunications and Information Administration (NTIA) − Mr. Julius Knapp, Chief, Office of Engineering and Technology, FCC − Mr. Harold “Stormy” Martin, Director, PNT National Coordination Office (NCO) 3

8/9/2018 Analysis of Ligado May 2018 Proposal and Assessment August 2018 PNTAB Bottom Line Up Front • The PNTAB strongly recommends disapproval of Ligado’s amended proposal for ~10 watt transmitters of May 31, 2018 2 1

8/9/2018 Summary of the latest Ligado Proposal: 1. Completely abandons terrestrial use of the 1545-55 MHz band 2. Reduces Power from 1.5kW to ~10 Watts in 1526-36 MHz band 3. Unspecified distance between Transmitters 4. Monitoring up to users, who must use a call-in number 5. Proposal asserts that it resolves all aviation issues (Aviation community filings disputes this) 6. Does not directly address most sensitive receivers – High Performance - but say “Ligado’s co-existence agreements with major GPS manufacturers and thousands of hours of empirical testing assure protection for all other classes of GPS devices”. Note: High-Performance receivers create over $30B per year in identified benefits to the US. • Ligado statement is not true. Top three manufacturers support international standard of 1 dB degradation, equivalent to a 25% drop in GPS signal power. • “New” Ligado 10W proposal violates noise standard by factors of 2500 or more at 400m spacing. 7. Proof of “assured protection” ascribed to Ligado-sponsored tests that were found inadequate & incomplete by independent review board. So “proof” is an erroneous statement. 8. Completely ignores ABC testing for most categories of receivers, which clearly shows proposal is unacceptable. 9. Continues to totally ignore effects on new GPS signals (L1C) and complementary GNSS systems (e.g. Galileo) 10. Military receiver impacts – i.e. M-code must be discussed by USAF who apparently 3 oppose the proposal Adjacent band interference concern “Upper” band is apparently off the table. Is this forever? “Lower” band Power reduced to ~10 Watts. Spacing not specified but original was ~400 meters. To meet broadband requirements it is possible that this will be less. Perhaps about 100 to 200 meters. Plausibly, perhaps Micro or Femtocells. Microcells typically are a watt at 500 Meters coverage (~1 km spacing). Femto cells are 100 milliwatts at 30 Meters. Assured PNT for All 4 2

8/9/2018 Summary Rationale for Disapproval • PNTAB believes use of GPS should be protected everywhere and for all current and future uses as directed by EXCOM letter in 2011. The “G” in “GPS” should really be Global. • At “new” ~10 watt power, tower spacing would have to be at least 20.4 kilometers to protect High Performance Receivers, even if only protected over 90% of coverage area • Viewed another way, with 400 meter spacing, Ligado power would have to be further reduced from ~10 watts to 0.0036 watts (2500 times lower) to protect tested High Performance Receivers, even if only protected over 90% of coverage area. • Asking the High Performance GPS Users to monitor the interference is totally unrealistic – they would not know how to do it, and would have no means to trace the problem to Ligado. • Ligado continues to ignore emerging use of modernized GPS and GNSS signals. Impacts to receivers tracking these wider bandwidth signals could be worse than for current GPS signals • If Ligado’s current license is approved, their spokesperson implied that over time they would expect to be allowed power increases. Temporary power reductions offered only to gain regulatory approval must be recognized as such and rejected. • Proposal is deliberately vague on geometry and spacing of towers. Ligado has repeatedly declined to provide these critical technical details to PNTAB to enable full and accurate assessment of interference. They have addressed Aviation (433m) and ignored High Performance Uses that have been shown to be much more sensitive to degradation. 5 The Evidence • Definition -Degradation Radius is the distance from the transmitter, beyond which the international interference standard is not violated. • That standard (1 dB degradation) is equivalent to a 25% drop in GPS signal power Conceptually, the radius defines a circle of degradation. -------------------------- • All major GPS manufacturers, the US Air Force, DOT, the Aircraft Industry and many others strongly support this International standard. • The DOT ABC report performed a detailed analysis in Appendix I. These scientific results form the basis for our analysis 6 3

8/9/2018 Overview: Transmitter Power, Transmitter Tower Spacing and Percentage Degradation Area for GPS receivers • Virtually all receivers will be degraded if they are too close to a Ligado Transmitter (overwhelm the “front-end”) • Consider a hypothetical case, where receivers can be degraded up to 10% of their operating area • Then degradation radius around each tower must be less than 0.17 times the spacing This is called the Degradation Limit Radius • This can be achieved by either reducing power or increasing spacing (decreasing tower density) • Earlier Ligado proposal is that tower spacing should be ~400 meters. Assured PNT for All 7 A visual Example: To insure additional 90% Area interference noise does not Protected – exceed 25% International spacing = 6.0 * Standard either: Degradation • Limit closest Transmitter Limit Radius Spacing for a given power Or 50% Area Why is Transmitter Spacing Critical? Protected – • Constrain Power for a given spacing = 2.4 * spacing (Reduce Degradation Radius) Degradation Limit Radius Green – Un-degraded Why is Transmitter Spacing Critical? 20% Area Protected – spacing = 2.1* Degradation Limit Radius 8 4

8/9/2018 Tradeoff – Degradation Radius versus % of Region Degraded – Relationship defined by simple, directly‐scalable geometry… Percentage Degraded Area for Various Degradation Radii Percentage of Area Degraded 100 90 80 No degradation exceeds 1 dB beyond 0.17 of Transmitter spacing 70 – or transmitter spacing is 1/0.17 60 times the Degradation Limit 50 Radius. 40 30 20 10 10% Degradation Limited to 10% of Area 0 0.00 0.10 0.20 0.30 0.40 0.50 0.60 Degradation Radius ‐ Fraction of Transmitter Spacing Assured PNT for All 9 Reminder: the only tests that met the PNTAB criteria were the DOT’s Adjacent Band Compatibility Ligado Key: Sponsored “ABC” Fully Compliant Non‐Compliant Assured PNT for All 10 5

8/9/2018 Example of ABC Test Results: Interference “Masks” (Tolerable Received Power from Adjacent Band –all receivers in each class) Band Received Power should be Lower below Ligado GPS Band lines 1530 1575 MHz MHz Assured PNT for All 11 On the same Scale – Received GPS power is less than 1/10000th of the Adjacent band degradation power. That is the reason GPS is located next to the MSS band GPS 1575 MHz Interference Power should be below lines Lower Ligado Band GPSBand signal is 1530 1/10,000th MHz Max ‐110 Interference Lower Ligado ‐120 Band GPS received power at 1530 ‐128.5 dBm = ‐130 MHz 1.41 e‐16 Watts 0.000000000000000141 Watts ‐140 Assured PNT for All 12 6

8/9/2018 Determining Allowable Transmitter power from ABC measured acceptable GPS Receiver degradation • The DOT also performed a detailed analysis of transmitter antenna patterns and transmitter power levels around the proposed transmitters. • They used the measured receiver Interference Masks to calculate allowable transmit power at various ranges from the Ligado Transmitters • Considered Classes of receivers (80 were tested): • High Precision and Networks (HPR) • General Aviation and Helicopters (non-certified) (GAV) • General Location/Navigation including emergency response vehicles (GLN) • Timing (TIM) • Celluar (CEL) 13 From Appendix I -DOT Test and Analysis: High Performance Receivers – Impacts of single 10W Ligado micro-Urban transmitter. * Degradation Radius is 3.4 Km. * Start loosing Low Elevation Satellites at 560m. Start Loosing All Satellites at 170m 560 m Loss of lower elevation Sats 3400 m = 170 m Degradation Loss of Radius all sats 14 7

8/9/2018 Hypothetical Tower Spacing Example for High Performance Receivers • Assumptions: • Ligado Power of 10 Watts • Hypothetical protection of only 90% of transmitter region • What is the closest spacing that would insure GPS protection from 25% noise increase? • Answer: 6.0 times the degradation radius. Previous example showed a 3400 Meter Degradation Radius from ABC Report Appendix I • Therefore: Protection of High Performance Receivers would require tower spacing of 20.5 km (12.7 miles), even if protected over only 90% of the cell area 10 watt transmitters clearly incompatible with use of High Precision Receivers (in fact All of Region is degraded at spacing of 5 km) 15 Using the ABC Degradation Radii ‐Calculation of minimum Ligado 10W separation for various Classes of GPS receivers Bounding Minimum Separation Between Degradation Radius Ligado 10 Watt Transmitters for Receiver Class (Meters) Class of GPS Receiver with 10W Transmitter % Region Protected (from ABC report – Appendix I) 90% 50% 10% High Performance/ High Productivity (HPR) 3400 meters 20,481 8190 6104 Emergency Vehicles and General Navigation (GLN) 1045 meters 6295 2815 2098 General Aviation and Helicopters (GAV) 1040 meters 6265 2802 2088 Timing (TIM) 293 meters 1765 789 588 Cell (CEL) 9.5 meters 57 26 19 We strongly believe 90% is the minimum Area Protection Criterion (maximum 10% degradation) 16 8

8/9/2018 For closer spacing - Maximum allowable Ligado Power to insure: GPS Protection for 90% of Transmitter Region . High Tower Spacing Performance Receivers 1000 400 200 100 Protected Meters meters meters meters All .023 W .0036 W .00089 W .00022 W Based on envelope of quantitative data taken from 40 Different HPRs, tested by DOT for Adjacent Band Compatibility Assured PNT for All 17 It may be worse – not included in analysis… • Multiple towers contribute additive noise • Reflections from ground and buildings can increase normal 1/R2 models by factors of over 10 (Factors of 15 measured in Las Vegas tests) • The newer GNSS signals have wider RF bandwidths for greater accuracy and A/J, but the receivers also may have greater sensitivity to the adjacent band power. In ABC tests, the Galileo E1 signal was more sensitive for HPRs. • The new military signal deliberately pushes energy away from the center frequency, closer to Ligado power. Assured PNT for All 18 9

8/9/2018 Clash – Fundamental Incompatibility Ligado Proposals ~ Date Power Spacing Comments Original "Thanksgiving" Proposal to 2010 15.6 kW 400 Meters FCC Quickly dropped power when PNT 2012 1.56 kW 400 Meters community protested 2015 1.56 kW 400 Meters Same as 2012 2017 19.8 W Would not say Verbal only: less than 400 Meters? 2018 9.8 W Did not specify New filing – claimed compatibility DOT Adjacent Band Compatibility Tests – 90% Protection Evaluation Assured PNT for All 19 PNTAB Recommendations • Strongly recommend rejecting latest Ligado 10 watt proposal • Does not meet PNT EXCOM January 2012 goal to protect “existing and evolving uses of space- based PNT services” • Not even close • Apply DOT Adjacent Band Compatibility (ABC) results and methodology to any future proposals 20 10

8/9/2018 Backups 21 Instead of constraining Minimum transmitter separation, consider Constraining the Ligado Transmitter Power and Still meeting the 90% Area Degradation Criterion 22 11

8/9/2018 Example of Transmitter constraints (Ligado originally requested 1.56 kW) Max Tolerable Ligado Power ‐ Watts 1 Not Tolerable .1 > 25% noise increase .01 3.8 milliwatts for 400m transmitter spacing – protection beyond 68m. .001 Tolerable Power at distance .0001 68 m. For 90% of Area to be protected, degradation .00001 radius must not exceed 0.17 times transmitter spacing. With 400 meter tower spacing, that distance would be 68 meters. 0 100 200 300 400 HighDegradation Precision Receiver Radius ‐ –Meters Maximum HighTolerable Lxxx Precision Receiver PowerTolerable – Maximum vs Distance Ligado Power vs Distance (all HPR receivers – Ligado at 1530 MHz) Assured PNT for All 23 To achieve Protection over 90% of Region by Applying a power constraint for various closest Distances Between Ligado Transmitters – At 1 kilometer, Ligado power must be less than 0.023 Watts Maximum Transmitted Power Degradation limited to 10% of Transmitter Region Maximum Transmitted Power 1 0.1 Watts 0.01 Protect All HPR… 1 Km Microcell Spacing? Ligado power must be less than 0.023 Watts 0.001 0 1000 2000 3000 4000 5000 Distance Between Ligado Transmitters (Meters) 24 12

8/9/2018 Three Levels of Adjacent Band Interference - ABI Already Presented 1. Increase of noise floor by >25% (the “1dB” criterion). We have used this level to define the “Degradation Radius” But there are two more serious levels: 2. Onset of total loss of Low Elevation Satellites – the “Loss of Low Elevation” radius. 3. Onset of total loss of all satellite signals – the “Total Loss” radius The calculation of % of regional area with a particular ABI effect proceeds in the same way as the 25% degradation (#1) 25 High Performance Receiver Loss of GPS signal 10 Watt transmitter Power (First Low elevation, then all Satellites) 560 m Loss of lower Sats 100% High Perfomance Receivers Percent of Area 90% Loosing Satellites Completely 3040 m > 25% 170 m Noise Increase Loss of all sats 80% for Spacing 0f 10 Watt Transmitter * Loss of Low Elevation Satellites 70% * Loss of all Satellites 60% Loss of low elevation Loss of low elevation satellites exceeds 50% 50% of Area when satellites exceeds 10% spacing is less than of Area when spacing 40% 1.4 kilometers. is less than 3.4 kilometers. 30% If 10 Watt spacing is 20% less than 500 meters HP Receivers begin 10% to lose all satellites over 50% of Area 0% 0 1000 2000 3000 Transmitter separation – Meters 26 13

8/9/2018 Analysis for all three levels of Interference was performed by DOT ‐ Examples for various classes of GPS Receivers follow Emergency Services and General Helicopter and General Aviation Receiver Degradation Navigation Receiver Degradation Radii Radii 102 m 10 Watt transmitter Power 10 Watt transmitter Power Loss of lower Sats 41 m Loss of 1040 m 1045 m all sats > 25% > 25% Noise Noise Increase Increase Timing Receiver Degradation Radii 10 Watt transmitter Power 87 m Begin Loss of lower elev. Sats 27 m Begin Loss of 293 m all > 25% sats Noise Increase 27 Q. What should the degradation radius be, such that no more than 10% of a given region is degraded? A. It scales directly with the separation distance and, for 10% regional degradation, is 0.17 times that separation. (At 0.57 times separation, 100% is degraded) 28 14

8/9/2018 Max Ligado Transmitter Power and tower density should be constrained by the % area that is degraded Geometric problem directly scales with spacing of transmitters (d) Furthest point from all is at 1/30.5 times d = 0.57 * d For Example: At 0.57 *d, 100% of the area would be covered What degradation radius would result, if degradation were limited to 10% of the area? Assured PNT for All 29 To Protect GPS for 90% of an area, with transmitters at spacing d, degradation radius must be less than 0.17 d. (i.e. Less than 17 % of the spacing) Whatever the Ligado spacing, to protect 90% of the Region, the degradation radius must not exceed 17% of the Spacing between Transmitters Assured PNT for All 30 15

8/9/2018 Results for other classes of receivers – Maximum Tolerable Power at certain sizes of Degradation Circle From DOT Adjacent Band Compatibility Tests Degradation Circle Radius In fact, using the ABC results and the proposed 10 Watt Ligado transmissions, 50 % of the 40 tested HPR receivers would be degraded beyond the 10% degradation circle at a transmitter spacing of 280 Meters 31 16


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