[time-nuts] The Demise of LORAN (was Re: Reference oscillatoraccuracy)

[Didier Juges]

I was shooting from the hip, I thought the DGPS signals were sent at UHF,
but maybe not, but that's not the point. The point is that you can
significantly affect DGPS operation without having to jam the GPS signal
itself. 

I found a reference saying the Monterey Bay jammer was jamming the DGPS
station, rather than the DGPS signal. I have not found the original article
I was looking for about it, but I think I remember that the boaters and
Coast Guards were the most affected, as you should expect because they rely
on and need the additional accuracy of the DGPS system.

Didier

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of David I. Emery
> Sent: Sunday, November 15, 2009 8:30 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] The Demise of LORAN (was Re: 
> Reference oscillatoraccuracy)
> 
> 
> 	That is the first I've heard of a UHF DGPS correction 
> transmission
> can you provide a frequency and modulation mode ?    Most I 
> know of are
> re purposed LF NDBs or similar transmitters in the 200 to 400 
> KHz or so range that transmit a PSK'd carrier with the DGPS 
> data at fairly low speed on it.
> 
> 	I have heard of cases of wide area GPS outages noted by 
> many folks with NON DGPS receivers (DGPS receivers  mostly 
> will just indicate no DGPS available and still show a pretty 
> good position) that were caused by UHF signals on the L2 
> frequency... though I am sure there are incidents of 
> accidental interference to LF or other distribution of DGPS.
>