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© 2011 Stansell Consulting

Do LightSquared and the FCC Threaten GPS?

Tom StansellStansell Consulting

Tom@Stansell.com

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Slide 2© 2011 Stansell Consulting

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.

The Lighthouse Story

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Slide 3© 2011 Stansell Consulting

GPS versus an Important National Priority?

Adobe Acrobat Document

Link to: “President Obama Details Plan to Win the Future through Expanded

Wireless Access”

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Slide 4© 2011 Stansell Consulting

Could Political Influence be Part of the Process?

Adobe Acrobat Document

Adobe Acrobat Document

Adobe Acrobat Document

Adobe Acrobat Document

Letter from the National Legal and

Policy Center

Editorial from The

Washington Times

Article in The

Washington Examiner

Article in USA Today

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Slide 5© 2011 Stansell Consulting

What is the GPS Community Doing About the Threat?

www.saveourgps.org

Save Our GPS Website

Adobe Acrobat Document

Testimony of Jim Kirkland, Vice

President and General Counsel of Trimble Navigation Limited

seg-gps-1.mp3 seg-gps-2.mp3

CBS Radio Reports

http://licensing.fcc.gov/cgi-bin/ws.exe/prod/ib/forms/reports/related_filing.hts?f_key=-216679&f_number=SATMOD2010111800239

Link to Documents Filed with the FCC

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Slide 6© 2011 Stansell Consulting

GPS Concerns and Numbers

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Slide 7© 2011 Stansell Consulting© 2011 Stansell Consulting

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

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Slide 8© 2011 Stansell Consulting© 2011 Stansell Consulting

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

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Slide 9© 2011 Stansell Consulting

NTIA Frequency Allocation Chart

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Slide 10© 2011 Stansell Consulting

MSS and GNSS Allocations

24 MHz

51MHz

S-E is Space to Earth

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Slide 11© 2011 Stansell Consulting

FCC Table of Allocations

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Slide 12© 2011 Stansell Consulting

Page 31 of FCC Table of Allocations

GNSS

MSS

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Slide 13© 2011 Stansell Consulting

LightSquared Signal Characteristics

-160 dBW/Hz-150 dBW/Hz

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Slide 14© 2011 Stansell Consulting

1525 1530 1535 1540 1545 1550 1555 1560 15651520

0 dB

-10 dB

-20 dB

-30 dB

-40 dB

-50 dB

GNSSMSSOther~1585 W

EIRP~1585 W

EIRP

Transmitter Bandpass Filters

32 dBW/10 MHz22 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

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Slide 15© 2011 Stansell Consulting

Free Space Propagation Loss

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Slide 16© 2011 Stansell Consulting

Potential 3rd Order Intermod Products

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Slide 17© 2011 Stansell Consulting

Closing Thoughts

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Slide 18© 2011 Stansell Consulting

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.

The LightSquared Dilemma