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gpspassion
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HIPAR
USA
29 Posts |
 Posted - 12 mai 2011 : 22:44:10
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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
93393 Posts |
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danham
USA
7339 Posts |
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HIPAR
USA
29 Posts |
Posted - 20 mai 2011 : 00:10:14
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“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
93393 Posts |
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gpspassion
93393 Posts |
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HIPAR
USA
29 Posts |
Posted - 27 mai 2011 : 23:52:31
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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 |
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gpspassion
93393 Posts |
Posted - 28 mai 2011 : 20:34:54
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| 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. |
Discounts and Assistance/Réductions et Assistance (Club GpsPasSion) / Où commencer? |
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HIPAR
USA
29 Posts |
Posted - 31 mai 2011 : 21:06:47
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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 |
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HIPAR
USA
29 Posts |
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gpspassion
93393 Posts |
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HIPAR
USA
29 Posts |
Posted - 21 juin 2011 : 23:48:40
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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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Lightsquared - GPS Jamming - FCC Pulls the Plug
