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 Lightsquared - GPS Jamming - FCC Pulls the Plug
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gpspassion

94032 Posts

Posted - 12 mai 2011 :  21:27:15  Show Profile  Visit gpspassion's Homepage  Reply with Quote
Thanks for the update. I thought a report by the "Technical Working Group" was due on April 15th, but I don't see anything here: http://saveourgps.org/related-articles.aspx

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HIPAR

USA
29 Posts

Posted - 12 mai 2011 :  22:44:10  Show Profile  Reply with Quote
For those who are interested in the testing and results, links to the important documents are here:

http://www.pnt.gov/interference/lightsquared/

The next Lightsquared report is due on 16 May 2011 and the final report is due mid June.

There is also an independent report to be prepared by Space-Based PNT National Executive Committee. Apparently there is some shared use of assets between the two testers. Notice the first responders were requested to participate by the US Government FAA; not the Lightsquared working group.

Evidently, the US government testers will also prepare a classified report. Weapons vulnerability is typically classified information.

--- CHAS
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gpspassion

94032 Posts

Posted - 13 mai 2011 :  00:41:14  Show Profile  Visit gpspassion's Homepage  Reply with Quote
Thanks, I'll add that link to the first message. I had a quick look at the April 15th report, it's a very thorough document. No test results yet as far as I can tell.

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danham

USA
7442 Posts

Posted - 18 mai 2011 :  15:52:26  Show Profile  Visit danham's Homepage  Reply with Quote
Testing is underway in Las Vegas:

http://www.lasvegassun.com/news/2011/may/14/testing-new-wireless-network-could-cause-gps-outag/

-dan

- Nüvi forum moderator -
Nüvi 760 in a '14 VW GTI & zumo 660 on a BMW F800 ST
Guide to working with pre-programmed routes: >> details <<
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HIPAR

USA
29 Posts

Posted - 20 mai 2011 :  00:10:14  Show Profile  Reply with Quote
“GPS is really nice, but we’ve got a backup,” said Las Vegas Fire & Rescue spokesman Tim Szymanski. “We might be a little bit inconvenienced, but we’re not going to lose anything on the call.”

Fire trucks and police cars are hooked with GPS units to help officers respond to distress calls, but it’s really just an added level of insurance that’s mostly for convenience, officials said.

“All of our officers know how to read a map,” said Metro Police spokesman Bill Cassell. “They know how to look up an address, find that address on a map, and then drive to it ... and we even still know how to triangulate off of mountaintops and give aircraft cardinal bearings to help land search-and-rescue mission flights.”

In other words, these guys couldn't care less if GPS goes down.

Well, I can read a map and follow a compass course too. Does that mean I want to go back to that? Really, I'm 'Up to Here' with those kinds of map and compass comments.

--- CHAS

Edited by - HIPAR on 20 mai 2011 00:13:34
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gpspassion

94032 Posts

Posted - 20 mai 2011 :  06:06:46  Show Profile  Visit gpspassion's Homepage  Reply with Quote
Yes, it's completely beyond the point...maybe taken out of context and he meant that they were trained to work without having to rely on GPS systems.

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gpspassion

94032 Posts

Posted - 27 mai 2011 :  06:54:55  Show Profile  Visit gpspassion's Homepage  Reply with Quote
On a related topic, Homeland Security looks into interference to the GPS system in general : http://www.insidegnss.com/node/2603

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HIPAR

USA
29 Posts

Posted - 27 mai 2011 :  23:52:31  Show Profile  Reply with Quote
No surprises, just conformation of the obvious .. Lightsquared vs GPS aviation:

http://www.insidegnss.com/node/2628

quote:
RTCA Report Show Serious LightSquared Interference to GPS Aviation --- An executive summary of a special report by RTCA Inc. Special Committee 159 released today (May 27, 2011) indicates that GPS aviation receivers would experience serious interference from transmission planned by LightSquared in the upper portion of the 1525–1559 MHz spectrum adjacent to the GPS L1 band.

Conducted in response to a request from the Federal Aviation Administration (FAA) to address the issue of compatibility between the operation of a terrestrial wireless broadband network, the study concludes that “the current LightSquared terrestrial authorization [from the Federal Communications Commission, FCC] would be incompatible with the current aviation use of GPS. . . .”

Among the RTCA SC159 recommendations was the following: “From an aviation perspective, LightSquared upper channel operation should not be allowed.” The full report will be delivered to the FAA next Friday. (...)
[ed]

--- CHAS
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HIPAR

USA
29 Posts

Posted - 28 mai 2011 :  16:57:46  Show Profile  Reply with Quote
Here are some preliminary results of a 'Live Sky' tower test conducted at Boulder City NV. Several precision survey GPS receivers were subjected to Lightsquared signals.

Reference Eric Gakstatter's presentation (Slide 27):

http://event.on24.com/event/31/14/42/rt/1/documents/slidepdf/gnss_marketinsightswebinar_ppt_052611.pdf


•Wide-band (20+Mhz -typical of L1/L2 receivers) began feeling the effects of LS within 1,800m of the tower and jammed within 1,600m.
•Medium-band (12MHz) L1 receivers began feeling the effects of LS within 1,200m of the tower and jammed within 1,000m.
•Test results are conservative.
•LS tower spacing upon build-out is similar to cell phone towers. Given the test results and project tower spacing, huge urban areas will be jammed for GPS, and even more so for high-precision GPS receivers.


During testing, the tower was operating at reduced power:

http://www.gpsworld.com/gnss-system/lightsquared-las-vegas-test-towers-flawed-fcc-filing-shows-11679

--- CHAS



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gpspassion

94032 Posts

Posted - 28 mai 2011 :  20:34:54  Show Profile  Visit gpspassion's Homepage  Reply with Quote
Thanks for the link, it looks like some companies in that presentation are coming up with solutions to make GPS work after Lightsquared gets deployed...the audience must have been perplexed. The "guardband" concept in that presentation is interesting, might be the way to go, but it would have to be tested of course.

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HIPAR

USA
29 Posts

Posted - 31 mai 2011 :  21:06:47  Show Profile  Reply with Quote
A preliminary interference report from Deere & Company:

On the FCC comment page for the Lightsquared action SATMOD2010111800239:

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

Find Deere Ex Parte (OET 5-26-2011) posted on 05/27/2011

That document discloses a Deere & Company presentation to the FCC Office of Engineering and Technology.

Quote:

'Deere explained that, in the course of its careful technical analysis undertaken in the time available, Deere’s engineers have determined that there is currently no practicable technical solution, or solutions in combination, available to avoid or substantially mitigate interference from the LightSquared’s base stations to Deere’s existing precision GPS system and to similar systems operated by others particularly in the agriculture and construction industries'.

Check out the titles of those in attendance. Someone in that group of 'technologists' should have raised the red flag signaling trouble ahead.

The presentation is included. It contains interesting photographs showing the test setup in the White Sands NM anechoic chamber. Testing supports the validity of an earlier Deere interference analysis.

The Deere system consists of a precision widebanded L1 GPS receiver augmented by corrections downlinked by Inmarsat via their network of geostationary satellites. Deere notes Lightsquared jammed the downlink at the Holloman NM live sky test tower. Ironically, Lightsquared plans to operate within Inmarsat licensed spectrum and has paid them to rearrange their satellite channels.

--- CHAS
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HIPAR

USA
29 Posts

Posted - 01 juin 2011 :  23:43:53  Show Profile  Reply with Quote
Here's a direct link to the Deere comment:

http://licensing.fcc.gov/myibfs/download.do?attachment_key=891387
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HIPAR

USA
29 Posts

Posted - 16 juin 2011 :  19:55:15  Show Profile  Reply with Quote
Lightsquared has been granted two more weeks for submission of their interference test report. Its now due 01 July 2011:

http://licensing.fcc.gov/myibfs/download.do?attachment_key=894067

The GPS industry contends Lightsquared should submit what's finished and supplement the report when the work is finished:

http://licensing.fcc.gov/myibfs/download.do?attachment_key=894155

OnStar (General Motors) wants more study before the LightSquared network is allowed to operate. Their test report filed with FCC:

http://licensing.fcc.gov/myibfs/download.do?attachment_key=893548

--- CHAS

Edited by - HIPAR on 18 juin 2011 22:26:48
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gpspassion

94032 Posts

Posted - 21 juin 2011 :  05:40:02  Show Profile  Visit gpspassion's Homepage  Reply with Quote
This just in, Lightsquared think they have a "fix"...that Trimble qualify as "bordering on the bizarre"! They're planning on limiting their emissions to the lower range of their allotted spectrum, i.e. 1526 to 1536 Mhz instead of the full 1525 through 1559 they own. The GPS L1 band uses the 1575.42 MHz frequency. Unfortunately they acknowledge that this is still causing problems to some high-precision GPS systems (surveying as opposed to Airplane GPS one would hope). Can't see how that can pass muster...

Details here : http://www.fiercewireless.com/story/lightsquared-will-use-lower-spectrum-bands-avoid-gps-interference/2011-06-20

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HIPAR

USA
29 Posts

Posted - 21 juin 2011 :  23:48:40  Show Profile  Reply with Quote
FCC has granted Lightsquared more time to submit its final working group interference report. Meanwhile, an independent report prepared for the Space-Based PNT National Executive Committee has become available:

http://www.govexec.com/pdfs/061711bb1.pdf

Data proves Lightsquared operations on the upper 10 MHz channel are not compatible with current certified avionics but it does suggest they might transmit in the lower 10 MHz channel without causing interference.

Equipments remaining most susceptible to interference are high precision units for survey and science. Lightsquared contends this is only 0.5% of the installed base. Are they implying these minority users can be sacrificed?

Complicating matters, satellite provider Inmarsat currently operates in that lower channel. Lightsquared has a deal with them to use that spectrum and, evidently, has persuaded them to accelerate spectrum clearing.

FCC is obviously sympathetic to Lightsquared but they finally gave way to Congressional pressures. They will accept public comments before finalizing Lightsquared's license.

--- CHAS
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