RE: [Discuss-gnuradio] gnu Radio and Mode S (1090 MHz)

[Nick Foster]

Andrew,

Eric Cottrell has written a complete Mode S receiver for gnuradio, using a USRP 
with a DBS-RX daughterboard. I also use a 1090MHz SAW filter and an LNA in my 
setup to get better results. Eric's software has not been ported to the current 
gnuradio architecture and uses the older "blks" interface. 

I rewrote Eric's software from scratch last spring to achieve better processing 
at lower sample rates, and to use a more optimal bit slicer for coping with 
FRUIT. I haven't released the software yet -- it is working with the latest 
gnuradio trunk, but I haven't gotten around to cleaning up the code to the 
point where I'm not embarrassed to look at it.

It sounds like you're more interested in sampling data that you already have in 
demodulated PPM form, from a receiver you already own. If that's the case, the 
USRP is probably overkill, but it will certainly work if you use an LFRX as the 
front end board. If you add the DBS-RX to the USRP, you've all but obviated the 
need to use the SBS-1 you have in your current setup.

Nick

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> From: address@hidden
> To: address@hidden
> Date: Wed, 17 Mar 2010 05:58:40 +1000
> Subject: [Discuss-gnuradio] gnu Radio and Mode S (1090 MHz)
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> Hello
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> Sorry if this is a duplicate.
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> I am using my digital scope to capture data and pipe it to a
> flat file where I can look at it in LINUX (gdsh USB and perl)
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> I am attempting to decode 1090 MHz transponder
> signals.
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> I know what I am looking for. ( I do this for a
> job)
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> I am on the hunt for better hardware and software to do the
> job under LINUX.
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> I simply need a faster better capture soluition that will
> allow me to up the through put of my signal analysis.
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> Can someone suggest ? I see some work has already been done on
> gnu-radio in this area.
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> At the moment I am processing csv capture files from the
> scope.But it takes seconds to grab the data from the scope.
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> Does gnu-radio have a module or code that would let me sample
> and save ? I can do the rest. Maybe a scope function ? samples vs
> time.
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> The data rate is 1 MHz for Mode S.
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> I have the 1090 MHz receiver, actually got 2. SBS-1 with video
> out (0-2Volts)
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> Here are some captures I have done so far.
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> http://vk4tec.no-ip.org/adsb_gds1022/
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> Would the USRP and some LINUX code help me out ?
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> I can program, in perl, python should not be too hard to
> grasp. C, so so .
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> Here is my website
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> www.tech-software.net
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> Andrew Rich VK4TEC
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> 17/03/2010
                                          
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