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Do LightSquared and the FCC Threaten GPS?. Tom Stansell Stansell Consulting [email protected]. The Lighthouse Story. Presumed transcript of a radio conversation between a US naval ship and Canadian authorities (CND) off the coast of Newfoundland. - PowerPoint PPT Presentation
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Stans el lCons u lting
RL
© 2011 Stansell Consulting
Do LightSquared and the FCC Threaten GPS?
Tom StansellStansell Consulting
Stans el lCons u lting
RL
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
Stans el lCons u lting
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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 156515200 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