Re: [time-nuts] SDR GPS
Magnus, You may want to take a look at: http://sourceforge.net/projects/osgps/files/SoftOSGPS/SoftOSGPS2.0/ Regards, Doug, K4CLE Connected by DROID on Verizon Wireless -Original message- From: Magnus Danielson mag...@rubidium.dyndns.org To: time-nuts@febo.com Sent: Wed, Nov 30, 2011 00:18:40 GMT+00:00 Subject: Re: [time-nuts] SDR GPS On 24/11/11 12:19, Poul-Henning Kamp wrote: Has any of you played with this: http://www.sparkfun.com/products/8238 I have. I managed to log data, write code to use FFT correlation search and then lock-up to a good strong bird and decode the sub-code. One has to look in a few books to get it but it's fun. Much harder to real-time decode, but I didn't spend quality time on achieving an efficient digital RF section. The dataformat is inefficient with only 2 out of 8 bits used, so one might consider stuffing the bits, but it would be a trivial fix. 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] SDR GPS
On 24/11/11 12:19, Poul-Henning Kamp wrote: Has any of you played with this: http://www.sparkfun.com/products/8238 I have. I managed to log data, write code to use FFT correlation search and then lock-up to a good strong bird and decode the sub-code. One has to look in a few books to get it but it's fun. Much harder to real-time decode, but I didn't spend quality time on achieving an efficient digital RF section. The dataformat is inefficient with only 2 out of 8 bits used, so one might consider stuffing the bits, but it would be a trivial fix. Cheers, Magnus There is also a limitation in the orginal module limiting continous data collection to 30(?) seconds. You need to remove a timer in the (USB) microcontroller on the device and recompile. This was no problem with open source tools. -- Björn ___ 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] SDR GPS
On 24/11/11 12:19, Poul-Henning Kamp wrote: Has any of you played with this: http://www.sparkfun.com/products/8238 I have. I managed to log data, write code to use FFT correlation search and then lock-up to a good strong bird and decode the sub-code. One has to look in a few books to get it but it's fun. Much harder to real-time decode, but I didn't spend quality time on achieving an efficient digital RF section. The dataformat is inefficient with only 2 out of 8 bits used, so one might consider stuffing the bits, but it would be a trivial fix. 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] SDR GPS
Quoting Poul-Henning Kamp p...@phk.freebsd.dk: Has any of you played with this: http://www.sparkfun.com/products/8238 www.gpscreations.com/Products_GPS1A.html looks like a version you can still purchase. But for the $500 they want I'd spend a little more and get a real SDR useful for other projects (QS1R etc.) and then homebrew a single-chip gps front end (MAX2769B etc.) and feed the 4 MHz IF to the SDR. More importantly, that device says it uses this open source gps signal processing package: sourceforge.net/projects/osgps/develop ___ 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] SDR GPS
On Thu, 24 Nov 2011 10:36:52 -0500 Bob Paddock bob.padd...@gmail.com wrote: Anyone look at the the one from Parallax that Radio Shack is selling for less than $50? http://www.parallax.com/Store/Sensors/CompassGPS/tabid/173/CategoryID/48/List/0/SortField/0/Level/a/ProductID/644/Default.aspx http://www.radioshack.com/product/index.jsp?productId=12302298 It says it is an antenna, do look at the specs closer. These are just standard Sirf based GPS receivers with packaged together with the antenna. Ie these are hardware receivers not SDR. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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] SDR GPS
On 11/24/11 9:33 AM, Collins, Graham wrote: Perhaps not in the same league or with the same gee-whiz appeal as a SDR GPS receiver but how about your own DIY GPS receiver: http://dangerousprototypes.com/2011/11/24/homemade-gps-receiver/ and the authors web page: http://www.holmea.demon.co.uk/GPS/Main.htm Yes, indeed.. that's sort of the other approach to building receivers, with a first mixer and filtering at IF. These days, most people just amplify and filter at the L1,L2,L5 frequencies and sample the 1 bit output at an appropriate rate (38-39 MHz). With Holme's approach, you need to synthesize the 1.5 GHz LO, which takes more gates, parts, etc. ___ 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] SDR GPS
Has any of you played with this: http://www.sparkfun.com/products/8238 -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] SDR GPS
On Thu, 24 Nov 2011 11:19:37 + Poul-Henning Kamp p...@phk.freebsd.dk wrote: Has any of you played with this: http://www.sparkfun.com/products/8238 I had a look at this (and a few other GPS SDR solutions) back a year or two ago and decided that they are either way too expensive or do not lend themselves well for time-nutty experimentation and are still too expensive. I guesstimate that a L1 GPS SDR receiver (SAW filter + LNA + down mixer + filter + second downmixer + filter + 8bit 40MHz ADC + FPGA) could be build with a budget of 500CHF at single pieces, rivaling the price of the sparkfun device you mentioned, while being 1) fully documented and 2) could lend itself to tinkering. Hence i dont think it's worth buying such a device (unless you are a software only guy who sees hardware as a necessary evil). An L1 + L2 receiver should be not that much more expenive, but the availability of filters for the L2 range is bad (you'd have to build one in microstrips) and depending on the exact design of the IF stage you'd have to doublicate the L1 path earlier or later for the L2 path. Hence i gues, a L1 + L2 reciever should have an additional cost of 100-200CHF (to the L1 only receiver) Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ 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] SDR GPS
Pricey, but allows to fly on high-attitude/speed. The region where money ist not so important ;-) - Henry Poul-Henning Kamp schrieb: Has any of you played with this: http://www.sparkfun.com/products/8238 -- ehydra.dyndns.info ___ 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] SDR GPS
On 11/24/11 3:38 AM, Attila Kinali wrote: On Thu, 24 Nov 2011 11:19:37 + Poul-Henning Kampp...@phk.freebsd.dk wrote: Has any of you played with this: http://www.sparkfun.com/products/8238 I had a look at this (and a few other GPS SDR solutions) back a year or two ago and decided that they are either way too expensive or do not lend themselves well for time-nutty experimentation and are still too expensive. I guesstimate that a L1 GPS SDR receiver (SAW filter + LNA + down mixer + filter + second downmixer + filter + 8bit 40MHz ADC + FPGA) could be build with a budget of 500CHF at single pieces, rivaling the price of the sparkfun device you mentioned, while being 1) fully documented and 2) could lend itself to tinkering. Hence i dont think it's worth buying such a device (unless you are a software only guy who sees hardware as a necessary evil). An L1 + L2 receiver should be not that much more expenive, but the availability of filters for the L2 range is bad (you'd have to build one in microstrips) and depending on the exact design of the IF stage you'd have to doublicate the L1 path earlier or later for the L2 path. Hence i gues, a L1 + L2 reciever should have an additional cost of 100-200CHF (to the L1 only receiver) Attila Kinali A typical spaceflight multiband design has a LNA and wideband filter up front (500MHz) followed by 3 parallel chains of filters and amps followed by a single bit quantizer. You might be able to find those ceramic filter based filters, which are reasonably small (Lark Engineering and others make these). If it was a full custom, the filters might cost a bit in NRE, but since others are also doing GPS, it might be a stock item. There's an ION paper from earlier this year by Courtney Duncan that describes our receiver. : Duncan, C.B., Robison, D.E., Koelewyn, C. Lee, Software Defined GPS Receiver for International Space Station, Proceedings of the 2011 International Technical Meeting of The Institute of Navigation, San Diego, CA, January 2011, pp. 982-988. http://trs-new.jpl.nasa.gov/dspace/handle/2014/41781 http://hdl.handle.net/2014/41781 ___ 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] SDR GPS
On Thu, Nov 24, 2011 at 6:19 AM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: Has any of you played with this: http://www.sparkfun.com/products/8238 Anyone look at the the one from Parallax that Radio Shack is selling for less than $50? http://www.parallax.com/Store/Sensors/CompassGPS/tabid/173/CategoryID/48/List/0/SortField/0/Level/a/ProductID/644/Default.aspx http://www.radioshack.com/product/index.jsp?productId=12302298 It says it is an antenna, do look at the specs closer. -- http://blog.softwaresafety.net/ http://www.designer-iii.com/ http://www.wearablesmartsensors.com/ ___ 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] SDR GPS
If you want altitude and speed, I recommend the Lassen IQ. ~$25 USD receiver. Good to 18000 meters (59k feet) and 500m/s (1118 MPH). You can exceed any ONE of these specs, but not both. Not really useful for timenuttery though but used often in high altitude balloons. -Bob On Thu, Nov 24, 2011 at 5:04 AM, ehydra ehy...@arcor.de wrote: Pricey, but allows to fly on high-attitude/speed. The region where money ist not so important ;-) - Henry Poul-Henning Kamp schrieb: Has any of you played with this: http://www.sparkfun.com/**products/8238http://www.sparkfun.com/products/8238 -- ehydra.dyndns.info __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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] SDR GPS
Perhaps not in the same league or with the same gee-whiz appeal as a SDR GPS receiver but how about your own DIY GPS receiver: http://dangerousprototypes.com/2011/11/24/homemade-gps-receiver/ and the authors web page: http://www.holmea.demon.co.uk/GPS/Main.htm cheers, Graham ve3gtc -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Robert Darlington Sent: November 24, 2011 11:51 To: ehy...@arcor.de; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] SDR GPS If you want altitude and speed, I recommend the Lassen IQ. ~$25 USD receiver. Good to 18000 meters (59k feet) and 500m/s (1118 MPH). You can exceed any ONE of these specs, but not both. Not really useful for timenuttery though but used often in high altitude balloons. -Bob On Thu, Nov 24, 2011 at 5:04 AM, ehydra ehy...@arcor.de wrote: Pricey, but allows to fly on high-attitude/speed. The region where money ist not so important ;-) - Henry Poul-Henning Kamp schrieb: Has any of you played with this: http://www.sparkfun.com/**products/8238http://www.sparkfun.com/products/8238 -- ehydra.dyndns.info __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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. ___ 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.
