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Do LightSquared and the FCC Threaten GPS?

Do LightSquared and the FCC Threaten GPS?. Tom Stansell Stansell Consulting Tom@Stansell.com. The Lighthouse Story. Presumed transcript of a radio conversation between a US naval ship and Canadian authorities (CND) off the coast of Newfoundland.

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Do LightSquared and the FCC Threaten GPS?

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  1. Do LightSquared and the FCC Threaten GPS? Tom Stansell Stansell Consulting Tom@Stansell.com

  2. The Lighthouse Story Presumed transcript of a radio conversation between a US naval ship and Canadian authorities (CND) off the coast of Newfoundland. US Ship: Please divert your course 0.5 degrees to the south to avoid a collision. CND reply: Recommend you divert your course 15 degrees to the South to avoid a collision. US Ship: This is the Captain of a US Navy Ship. I say again, divert your course. CND reply: No. I say again, you divert YOUR course! US Ship: THIS IS THE AIRCRAFT CARRIER USS CORAL SEA, WE ARE A LARGE WARSHIP OF THE US NAVY. DIVERT YOUR COURSE NOW!! CND reply: This is a lighthouse. Your call.

  3. GPS versus an Important National Priority? Link to: “President Obama Details Plan to Win the Future through Expanded Wireless Access”

  4. Could Political Influence be Part of the Process? Letter from the National Legal and Policy Center Editorial from The Washington Times Article in The Washington Examiner Article in USA Today

  5. What is the GPS Community Doing About the Threat? www.saveourgps.org Testimony of Jim Kirkland, Vice President and General Counsel of Trimble Navigation Limited Save Our GPS Website CBS Radio Reports Link to Documents Filed with the FCC http://licensing.fcc.gov/cgi-bin/ws.exe/prod/ib/forms/reports/related_filing.hts?f_key=-216679&f_number=SATMOD2010111800239

  6. GPS Concerns and Numbers

  7. How Can ATC Signals Affect GPS? • LightSquared plans 40,000 high power transmitters • Desensitization by overdriving RF amplifiers • Gain compression of RF/IF amplifiers with strong signals • Depends somewhat on number of signal sampling levels • AGC performance also can be adversely affected • Creating third order intermodulation products • In nonlinear GPS RF/IF due to strong input signals • Major threat to StarFire and OmniSTAR • Correction messages from Inmarsat in the MSS Band

  8. LTE Signal Characteristics • Base station requires a linear amplifier • Uses 4.5 MHz out of any 5 MHz band • Carrier spacing is 15 kHz, which is the data rate • Orthogonal Frequency Division Multiplexing (OFDM) • In a 10 MHz band, 600 subcarriers • Filling 600 x 0.015 = 9 MHz

  9. NTIA Frequency Allocation Chart

  10. MSS and GNSS Allocations 24 MHz S-E is Space to Earth 51MHz

  11. FCC Table of Allocations

  12. Page 31 of FCC Table of Allocations MSS GNSS

  13. LightSquared Signal Characteristics -160 dBW/Hz -150 dBW/Hz

  14. Transmitter Bandpass Filters 32 dBW/10 MHz 22 dBW/MHz -38 dBW/Hz -8 dBm/Hz • Filter only, does not account for spectral characteristics of the LTE waveform • Out of Band EIRP power density in GPS band stated to be -160 dBW/Hz

  15. Free Space Propagation Loss

  16. Potential 3rd Order Intermod Products

  17. Closing Thoughts

  18. The LightSquared Dilemma Presumed transcript of a radio conversation between LightSquared and the GPS Community. LightSquared: Please divert your course 0.5 degrees to the south to avoid a collision. GPS reply: Recommend you divert your course 15 degrees to the South to avoid a collision. LightSquared: This is the CEO of a Multi-billion Dollar Hedge Fund. I say again, divert your course. GPS reply: No. I say again, you divert YOUR course! LightSquared: THIS IS HARBINGER CAPITAL PARTNERS! WE ARE VERY INFLUENTIAL. DIVERT YOUR COURSE NOW!! GPS reply: This is GPS, a Vital National Infrastructure. Your call.

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