[time-nuts] GPS interference and history...

Lester Veenstra lester at veenstras.com
Thu Jun 9 19:55:16 UTC 2011


Yes, for instance the aviation industry, WAAS, which is in the L-Bans mobile
satellite assignment, (INMARSAT etc), that L^2 reuses and thus kills.


Lester B Veenstra  MØYCM K1YCM
lester at veenstras.com
m0ycm at veenstras.com
k1ycm at veenstras.com
 

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-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Mark Spencer
Sent: Thursday, June 09, 2011 8:42 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS interference and history...

I seem to recall that some of the high precision users also need to receive
a 
satellite delivered differential GPS signal outside of the GPS band.



----- Original Message ----
From: Jim Lux <jimlux at earthlink.net>
To: time-nuts at febo.com
Sent: Thu, June 9, 2011 12:32:42 PM
Subject: Re: [time-nuts] GPS interference and history...

On 6/9/11 12:22 PM, Chuck Forsberg WA7KGX N2469R wrote:
> According to the John Deere article, the higher performance GPS
> receivers, such as those used
> for agricultural application and IFR navigation have wider front ends to
> obtain more precise information
> from GPS signals. The LightSquared transmitters wouldn't pose such a
> problem if they were in orbit.
>> 

Exactly.. Deere (and others) designed based on the general understanding of
what 
the spectrum would look like.  Mostly satellite radiated (where, as others
have 
noted, you're limited to a few kW) and a few "fill-in" transmitters to
handle 
"urban canyons" and the like.. low power in general, and not in the middle
of a 
farm field in any case.

The L^2 scheme turned that on its head.. lots of high powered terrestrial 
transmitters, etc.



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