Re: [time-nuts] CGSIC: FW: New NANU 2014090
On Dec 17, 2014, at 1:38 PM, Jim Lux jim...@earthlink.net wrote: but there probably are some software receivers (open source?) out there.. I'll add to the list: Fellow time-nut Peter Monta's GNSS Firehose http://pmonta.com/blog/2014/06/17/new-gnss-firehose-board/ https://github.com/pmonta/GNSS_Firehose The designer of the NSL Primo, Michele Bavaro http://michelebavaro.blogspot.com, sells a better alternative to the US$500, L1-only GN3S, namely the SdrNav00 for EUR 220 http://www.onetalent-gnss.com/ideas/software-defined-radio/sdrnav00 One of these days, yours truly will be selling a cape for the BeagleBone Black SBC containing an L1-only Si 4150L (maybe I should rethink that) plus Xilinx LX45 FPGA www.jks.com/wrx/wrx.html which runs Andrew Holme's homemade software-defined GPS receiver http://www.aholme.co.uk/GPS/Main.htm Plus you get a shortwave SDR for free.. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CGSIC: FW: New NANU 2014090
Hi On Dec 16, 2014, at 7:01 PM, Jim Lux jim...@earthlink.net wrote: On 12/16/14, 3:36 PM, Magnus Danielson wrote: Paul, That is indeed the question. Considering that the signal is better supported, I hope the light goes on somewhere. The signals is all 1,023 Mchips/s, just a thad different. Should be possible to pull off if people want to do dual frequency without going full bandwidth. Then again, if you are willing to pay good money, you can get it today. what about one of the software receivers? I would think that making L2 and L5 filters isn't that tough, so all you need is the back end. ….. and the back end is where all the work is. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CGSIC: FW: New NANU 2014090
Jim, Bob, On 12/17/2014 01:06 AM, Bob Camp wrote: Hi On Dec 16, 2014, at 7:01 PM, Jim Lux jim...@earthlink.net wrote: On 12/16/14, 3:36 PM, Magnus Danielson wrote: Paul, That is indeed the question. Considering that the signal is better supported, I hope the light goes on somewhere. The signals is all 1,023 Mchips/s, just a thad different. Should be possible to pull off if people want to do dual frequency without going full bandwidth. Then again, if you are willing to pay good money, you can get it today. what about one of the software receivers? I would think that making L2 and L5 filters isn't that tough, so all you need is the back end. ….. and the back end is where all the work is. There is a fair amount of work along the full path. LNA with some L2 and L5 filters is pretty easy. I think you still want to have a correlator baseband processing in say an FPGA. There is naturally stuff to be done on the L2C and L5 modulated signals, but it goes in a relatively slow paze so that even modest processors can keep up with it. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CGSIC: FW: New NANU 2014090
On 12/16/14, 4:06 PM, Bob Camp wrote: Hi On Dec 16, 2014, at 7:01 PM, Jim Lux jim...@earthlink.net wrote: On 12/16/14, 3:36 PM, Magnus Danielson wrote: Paul, That is indeed the question. Considering that the signal is better supported, I hope the light goes on somewhere. The signals is all 1,023 Mchips/s, just a thad different. Should be possible to pull off if people want to do dual frequency without going full bandwidth. Then again, if you are willing to pay good money, you can get it today. what about one of the software receivers? I would think that making L2 and L5 filters isn't that tough, so all you need is the back end. ….. and the back end is where all the work is. but there probably are some software receivers (open source?) out there.. http://gps.psas.pdx.edu/ appears to have stalled for lack of hardware http://gnss-sdr.org/ This article provides details about the support that GNSS-SDR offers for real-time operation using the GNSS USB front-end SiGe GN3S Sampler v2. Unfortunately, this product has been retired and replaced by a newer version v3, but we hope this still can be useful to v2 users. The RTL dongle might a choice, but the Elonics E4000 flavor has a whole from 1100-1250, and since L2 is at 1227, that's a problem. http://www.taroz.net/gnsssdrlib_e.html appears to support all the frequencies and modulations the GN3S sampler is available from SparkFun for $500.. if they have them in stock. I'm not sure it can tune the band, though: they don't seem to have a block diagram and I'm not going to read the source code to figure it out. Seems from the SiGe datasheet that it's L1 only, but the well equipped timenut might be able to fake the reference crystal to one that would tune L2 and L5. http://www.nsl.eu.com/primo.html seems to be hardware that can do all the stuff.. Maybe GBP800? in a nice box. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CGSIC: FW: New NANU 2014090
On 12/16/14, 4:29 PM, Magnus Danielson wrote: Jim, Bob, On 12/17/2014 01:06 AM, Bob Camp wrote: Hi On Dec 16, 2014, at 7:01 PM, Jim Lux jim...@earthlink.net wrote: On 12/16/14, 3:36 PM, Magnus Danielson wrote: Paul, That is indeed the question. Considering that the signal is better supported, I hope the light goes on somewhere. The signals is all 1,023 Mchips/s, just a thad different. Should be possible to pull off if people want to do dual frequency without going full bandwidth. Then again, if you are willing to pay good money, you can get it today. what about one of the software receivers? I would think that making L2 and L5 filters isn't that tough, so all you need is the back end. ….. and the back end is where all the work is. There is a fair amount of work along the full path. LNA with some L2 and L5 filters is pretty easy. I think you still want to have a correlator baseband processing in say an FPGA. well, yes.. but I don't know if there's any handy open source free cores out there for that. I do know grin of an implementation that does the acq and track in a pair of Xilinx 2-3000 parts and does the nav solution in a SPARC V8, but it's not open source and it's definitely export controlled. Seems that what's out there is mostly record bits and postprocess in C++ or Matlab Several textbooks even include it. There is naturally stuff to be done on the L2C and L5 modulated signals, but it goes in a relatively slow paze so that even modest processors can keep up with it. Indeed.. we do 24 channels (where channel is one PRN at one frequency) with a 3 frequency solution without making a 66 MHz LEON2 based SPARC sweat too much. That's why it would be intriguing if someone had the FPGA stuff out there. It would still be an expensive project, I suspect. Either you'd have a few $50-100 boards that would need interfacing and a lot of time, or a $1000 board with less time. One hopes that in a few years, multifrequency stuff will become available. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CGSIC: FW: New NANU 2014090
Hi On Dec 16, 2014, at 7:29 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Jim, Bob, On 12/17/2014 01:06 AM, Bob Camp wrote: Hi On Dec 16, 2014, at 7:01 PM, Jim Lux jim...@earthlink.net wrote: On 12/16/14, 3:36 PM, Magnus Danielson wrote: Paul, That is indeed the question. Considering that the signal is better supported, I hope the light goes on somewhere. The signals is all 1,023 Mchips/s, just a thad different. Should be possible to pull off if people want to do dual frequency without going full bandwidth. Then again, if you are willing to pay good money, you can get it today. what about one of the software receivers? I would think that making L2 and L5 filters isn't that tough, so all you need is the back end. ….. and the back end is where all the work is. There is a fair amount of work along the full path. LNA with some L2 and L5 filters is pretty easy. I think you still want to have a correlator baseband processing in say an FPGA. There is naturally stuff to be done on the L2C and L5 modulated signals, but it goes in a relatively slow paze so that even modest processors can keep up with it. Since these are “odd” signals, the hardware is only a small part of the problem. I would bet that the standard bits and pieces are only going to get you part of the way with these signals. The 10% hardware hours / 90% software hours likely applies here. Bob Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CGSIC: FW: New NANU 2014090
Jim, On 12/17/2014 01:46 AM, Jim Lux wrote: On 12/16/14, 4:29 PM, Magnus Danielson wrote: Jim, Bob, There is a fair amount of work along the full path. LNA with some L2 and L5 filters is pretty easy. I think you still want to have a correlator baseband processing in say an FPGA. well, yes.. but I don't know if there's any handy open source free cores out there for that. I do know grin of an implementation that does the acq and track in a pair of Xilinx 2-3000 parts and does the nav solution in a SPARC V8, but it's not open source and it's definitely export controlled. For that application it needs to break both the limits at the same time, for sure. Seems that what's out there is mostly record bits and postprocess in C++ or Matlab Several textbooks even include it. It's good for many purposes as you get yourself up to speed. There is naturally stuff to be done on the L2C and L5 modulated signals, but it goes in a relatively slow paze so that even modest processors can keep up with it. Indeed.. we do 24 channels (where channel is one PRN at one frequency) with a 3 frequency solution without making a 66 MHz LEON2 based SPARC sweat too much. That's why it would be intriguing if someone had the FPGA stuff out there. Indeed. I did a GPS correlator core once, but it had issues to fit the FPGA I had at hand at the time. The software receiver I did was not at all doing real-time, but it did do many of the crucial points and was a nice exercise. It would still be an expensive project, I suspect. Either you'd have a few $50-100 boards that would need interfacing and a lot of time, or a $1000 board with less time. One hopes that in a few years, multifrequency stuff will become available. Indeed. Maybe a complete implementation just needs to hit the web.. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] CGSIC: FW: New NANU 2014090
The Swift Navigation Piksi project may be of interest: http://swiftnav.com/piksi.html It has an FPGA for correlation with an ARM Cortex-M3 for tracking loops and navigation. The hardware and ARM firmware is open source, but the FPGA design is closed-source at the moment. However, I don't see why the FPGA would need adapting for use with L2C L5. I know the Swift Nav folks are looking into a multi-frequency product. One of the main obstacles is a commodity front-end solution, and antennas at reasonable prices. Henry On Tue, Dec 16, 2014 at 5:01 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Jim, On 12/17/2014 01:46 AM, Jim Lux wrote: On 12/16/14, 4:29 PM, Magnus Danielson wrote: Jim, Bob, There is a fair amount of work along the full path. LNA with some L2 and L5 filters is pretty easy. I think you still want to have a correlator baseband processing in say an FPGA. well, yes.. but I don't know if there's any handy open source free cores out there for that. I do know grin of an implementation that does the acq and track in a pair of Xilinx 2-3000 parts and does the nav solution in a SPARC V8, but it's not open source and it's definitely export controlled. For that application it needs to break both the limits at the same time, for sure. Seems that what's out there is mostly record bits and postprocess in C++ or Matlab Several textbooks even include it. It's good for many purposes as you get yourself up to speed. There is naturally stuff to be done on the L2C and L5 modulated signals, but it goes in a relatively slow paze so that even modest processors can keep up with it. Indeed.. we do 24 channels (where channel is one PRN at one frequency) with a 3 frequency solution without making a 66 MHz LEON2 based SPARC sweat too much. That's why it would be intriguing if someone had the FPGA stuff out there. Indeed. I did a GPS correlator core once, but it had issues to fit the FPGA I had at hand at the time. The software receiver I did was not at all doing real-time, but it did do many of the crucial points and was a nice exercise. It would still be an expensive project, I suspect. Either you'd have a few $50-100 boards that would need interfacing and a lot of time, or a $1000 board with less time. One hopes that in a few years, multifrequency stuff will become available. Indeed. Maybe a complete implementation just needs to hit the web.. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
