[time-nuts] From GPS World - Lightsquared has been given the goahead

[bownes]

Of the 2 lc orgs I administer or am a member of, and the roughly 8 other lc orgs I  interact with on a regular basis, only one uses lc certified gps equip. The others are all consumer grade or don't use gps. 

However, a slew of filings and letters from the lc community might not be a bad idea, if only to lay the groundwork for the inevitable lawsuits. 


On Feb 2, 2011, at 3:06 PM, Rex <rexa at sonic.net> wrote:

> On 2/2/2011 7:25 AM, jimlux wrote:
>> 
>> 
>> I got the impression that it wasn't modeled, but was an actual field test of some sort.  I'll have to go back and reread.
>> 
>> But, it's possible that the consumer receiver has better multipath and interference rejection, if only because it's newer. Aviation stuff takes longer to go through the approval cycle, so it tends to lag consumer electronics in terms of technology adoption.
>> 
>> 
> 
> From the paper submitted by the GPS manufactureres to the FCC
> http://www.gpsworld.com/gnss-system/signal-processing/lightsquared-jamming-report-11030
> 
> it seems they simulated the Lightsquared signal with test equipment and made measurements in an anechoic chamber of effects on GPS signal reception to a couple of popular GPS receivers. Using this data they extrapolated real-world effects with path loss calculations. Ironically, it probably wouldn't be legal or safe to make the jamming measurements in a real, open space, environment.
> 
> The paper says the Lightspeed transmitters can be up to around 15 kW EIRP in a band right adjacent to GPS. I would think filtering out that signal to avoid overload would be a daunting task.
> 
> 
> 
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