Re: [time-nuts] New timing receivers?
A couple of points I discovered while building these things. This morning I got an Adafruit Ultimate (MTK3999) and a uBlox neo-6M module. The first thing I discovered after looking at the specs , was that both have on board LDO 3.3V regulators, so you can feed them 5V without harm. I had wanted to make up an interface board with usb power and a DB9 serial interface for them , but found that I already had something that looked to fit the bill even though not the same size as these micro modules. I have some Trimble Resolution Ts and SMTs for which I have bought PPS-Piggy interface boards from Partially Stapled, marketed by Tindie.com (disclaimer as usual). I think they have been mentioned here. These two little modules interface perfectly. You just have to re-map the socket when wiring up. It looks like just about any of the modern boards will do so, though you won't get all the chip pin outs . The only issue for me this morning was picking up the TIMEPULSE(1PPS) from the neo-6M. Ideally , to get a robust pin-out I would have drilled a hole next to the 4 supplied, put a via in and then a standard pin. I don't have the tools to do that and even then it might have been iffy as the hole would go through the ground plane, leading to possible isolation issues. So what I did, was to use one of the mounting holes which are isolated and lead the wire from there to the chip pin 3 over the back of the module and up through the central hole. Soldering that end wasn't easy. I first tried tacking it directly to the chip pad after I had scraped it a little to remove any varnish, though I don't think there is any, but for some reason I could not get a good join. So I scraped of a couple of mm of the pin3 trace down to the copper. I went really carefully as I suspect it is just a few microns thick. Soldering the wire to the trace enabled me to get a good joint and both the 1PPS to pin and the LED work fine. I have photos: http://stratum1.d2g.com/images/new-gps-modules/new-gps-modules%20001.jpg http://stratum1.d2g.com/images/new-gps-modules/new-gps-modules%20001.jpg Le 29 avr. 2014 à 16:43, Attila Kinali a écrit : On Tue, 29 Apr 2014 08:02:06 -0400 (EDT) ewkeh...@aol.com wrote: Looks like they are doing exactly what I suggested as one of the alternatives for saw tooth correction. They have a VCTCXO in the module, with the computing power in their chip a no brainer. the question is how much will it cost and how important will it be for a GPSDO. Final cost at maximum accuracy is what counts Judging from their other parts, i would say resonable prices start from 20 pieces onwards. Attila Kinali -- I pity people who can't find laughter or at least some bit of amusement in the little doings of the day. I believe I could find something ridiculous even in the saddest moment, if necessary. It has nothing to do with being superficial. It's a matter of joy in life. -- Sophie Scholl ___ 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.
[time-nuts] New timing receivers?
I have done a PCB that has connectors/mounting holes for the Adafruit, Crius CN06 (uBlox Neo 6M), and Resolution-T and -SMD receivers. It has a DB9, 3.3V regulator, and MAX232A chip. It can drive the 1PPS signal (either polarity) to the CD signal on the DB9. Power to the circuitry can be raw input voltage or regulated from either a 2.1mm barrel connector or pin 9 of the DB9. There is a small prototyping area on one end of the board (includes some pads intended for an Atmel ATTINY85 processor). I can put the board on OSHPARK.COM shared projects if anybody is interested. They wind up costing $30 for three boards. I am waiting for the newest rev of the boards (with the ATTINY85 footprint) to arrive from OSHPARK in a few days. --- I already had something that looked to fit the bill even though not the same size as these micro modules. I have some Trimble Resolution Ts and SMTs ___ 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] New timing receivers?
Tom, Any progress on the Adafruit PPS study? (Hope this isn't a dupe. Yahoo's mail scripts have problems today.) Bob From: Tom Van Baak t...@leapsecond.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, April 28, 2014 1:56 PM Subject: Re: [time-nuts] New timing receivers? I don't see that behavior. Looking at ~24 hours of data I have 1,024 unique (x,y) coordinates (as reported by the GGA sentence). The standard deviation of the error relative to the median (x,y) position is 1.2 meters. Paul, I agree. I have 30 days of Adafruit data; the position is never quite static, bounces around over a couple of meters as one would expect for a receiver in 3D mode. Send me email off-list for details about lat/lon/alt RMS deviation and scatter plots. On the other hand, I have a second identical Adafruit receiver with distinctly different deviation patterns. I'm working through that mystery now. Nothing with this hobby ever ends up being a simple quick test. Thanks, /tvb ___ 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] New timing receivers?
On Sun, 27 Apr 2014 20:43:44 -0700 Hal Murray hmur...@megapathdsl.net wrote: The uBlox-6 has a free running osc. If it wasn't free running, it would be a GPSDO. Their new LEA-M8F seems to be a GPSDO. The 30.72MHz output frequency suggests the intended use in cell phone base stations. 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] New timing receivers?
Hi It’s been a few years since I played with the TBolt delay. At least on the one I messed with, it only did modulo 100 ns moves. Anything finer grained than 100 ns simply was ignored. Bob On Apr 27, 2014, at 11:32 PM, Tom Van Baak t...@leapsecond.com wrote: Jim, Most (all?) timing receivers allow you to virtually shift the 1PPS forwards and backwards to compensate for antenna delay or other factors. But the physical 1PPS output will still have clock quantization and the only way to deal with this is external h/w or s/w sawtooth correction. Imagine some GPS timing receiver with 50 MHz clock and 20 ns quantization. Each 1PPS is one of those 50 MHz clock edges. The sawtooth correction is some number between +/- 10 ns. If you were to add 1 ns to the antenna delay, the 1PPS output would still be one of those clock edges, but the sawtooth correction number would now be 1 ns less. So there is no electrical or mathematical advantage in doing this. Speaking of which, has anyone watched what happens if you change the antenna delay by 2000, 200, 20, or 2 ns in a TBolt GPSDO? /tvb - Original Message - From: Jim Miller j...@jtmiller.com To: time-nuts time-nuts@febo.com Sent: Sunday, April 27, 2014 8:05 PM Subject: Re: [time-nuts] New timing receivers? I spent some time reading the uBlox-6 documentation. I found the TIM-TP ubx message and format. I see that there is also the ability to feed back to the uBlox-6 time shift info for the PPS in 1ns increments. Does it make sense to feed the TIM-TP info back this way to provide correction? Or is an external delay line or TIC plus software the only way? Thanks jim ab3cv On Sat, Apr 26, 2014 at 7:59 PM, Jim Miller j...@jtmiller.com wrote: I'm reading though the manual for my recently acquired M12+T which I'm looking forward to using. I notice that the manual is dated 09FEB05. So the M12+T has been around for about a decade. Are there more recent timing receivers available now or has the ubiquity of the consumer GPS market distracted all investment from timing receivers except at the high end? Thanks Jim AB3CV ___ 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] New timing receivers?
Bob wrote: It's been a few years since I played with the TBolt delay. At least on the one I messed with, it only did modulo 100 ns moves. Anything finer grained than 100 ns simply was ignored. That is true of the jam synch (used when the current PPS timing is off by more than 50ns, generally during warmup), but not true (to my observation) of the cable delay compensation. Best regards, Charles ___ 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] New timing receivers?
On Mon, Apr 28, 2014 at 1:08 AM, Mark Sims hol...@hotmail.com wrote: I was playing with an Adafruit GPS, it appeared that if it thought you were not moving it would go into a pseudo-position-hold mode and the output coords would not change. I don't see that behavior. Looking at ~24 hours of data I have 1,024 unique (x,y) coordinates (as reported by the GGA sentence). The standard deviation of the error relative to the median (x,y) position is 1.2 meters. ___ 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] New timing receivers?
I don't see that behavior. Looking at ~24 hours of data I have 1,024 unique (x,y) coordinates (as reported by the GGA sentence). The standard deviation of the error relative to the median (x,y) position is 1.2 meters. Paul, I agree. I have 30 days of Adafruit data; the position is never quite static, bounces around over a couple of meters as one would expect for a receiver in 3D mode. Send me email off-list for details about lat/lon/alt RMS deviation and scatter plots. On the other hand, I have a second identical Adafruit receiver with distinctly different deviation patterns. I'm working through that mystery now. Nothing with this hobby ever ends up being a simple quick test. Thanks, /tvb ___ 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] New timing receivers?
On Mon, Apr 28, 2014 at 1:08 AM, Mark Sims hol...@hotmail.com wrote: When I was playing with an Adafruit GPS, it appeared that if it thought you were not moving it would go into a pseudo-position-hold mode and the output coords would not change. It took it a while to start outputting new coords when you started moving again. This test was at walking speeds. I had to walk maybe 100 feet before it started sending new coords. The 3339 chip has a command PMTK386 to set its Nav Speed Threshold. This is intended to prevent the position from drifting if the unit is stationary. You can also query the current setting with the PMTK447 command, and it should respond with a PMTK527. For details you can download the document GlobalTop PMTK command packet. There are several versions available on the web, the newest I was able to find is A11, at http://doxical.free.fr/resources/exstatic/PA6B_Flash/PMTK%20command%20packet-Complete-A11.pdf Note that the document version linked form the Adafruit website is not the newest, and that for some reason the 3318 and 3329 use a different command for this function. I believe the default setting for this option is a firmware option, so units may have different settings at power-up. My unit also seems to wander around, but I have not experimented to see if its location changes correspond to timing changes, or if changing the nav speed threshold affects the timing accuracy. BTW I have not seen the dropped PPS signals some have reported. I am using the Adafruit antenna outdoors, with a view of about half the sky, looking east. -- --Jim Harman ___ 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] New timing receivers?
In message CAKyJ6kZqOiByDU_CwkZpPiuvzigGh+mqe4O=dpwzz4wo9gr...@mail.gmail.com , Paul writes: Sawtooth (quantization) correction is probably the defining characteristic. Position Hold is what makes a GPS receiver timing, the sawtooth correction is icing on the cake. -- 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] New timing receivers?
On Sat, 26 Apr 2014 22:36:27 -0700 Chris Albertson albertson.ch...@gmail.com wrote: How does the u-bloc's performance compare to the M12+T?One of these is on my list of things to buy someday. I thought the M12+T had a 1-sigma error in the single digit nanoseconds.The u-bloc is newer it is even better? According to [1], the LEA6-T has a sigma of 3ns after sawtooth correction. Attila Kinali [1] https://www.u-blox.com/images/downloads/Product_Docs/Timing_AppNote_%28GPS.G6-X-11007%29.pdf -- I pity people who can't find laughter or at least some bit of amusement in the little doings of the day. I believe I could find something ridiculous even in the saddest moment, if necessary. It has nothing to do with being superficial. It's a matter of joy in life. -- Sophie Scholl ___ 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] New timing receivers?
Hi You might want to actually measure the GPS modules to look at their performance. Some of them (like the uBlox) can do much better than the published specs. Bob On Apr 27, 2014, at 4:25 AM, Attila Kinali att...@kinali.ch wrote: On Sat, 26 Apr 2014 22:36:27 -0700 Chris Albertson albertson.ch...@gmail.com wrote: How does the u-bloc's performance compare to the M12+T?One of these is on my list of things to buy someday. I thought the M12+T had a 1-sigma error in the single digit nanoseconds.The u-bloc is newer it is even better? According to [1], the LEA6-T has a sigma of 3ns after sawtooth correction. Attila Kinali [1] https://www.u-blox.com/images/downloads/Product_Docs/Timing_AppNote_%28GPS.G6-X-11007%29.pdf -- I pity people who can't find laughter or at least some bit of amusement in the little doings of the day. I believe I could find something ridiculous even in the saddest moment, if necessary. It has nothing to do with being superficial. It's a matter of joy in life. -- Sophie Scholl ___ 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] New timing receivers?
For a nice comparison of the M12+T, M12M, and ublox-6T, start with page 34, and especially note the ADEV plot on page 40: http://www.cnssys.com/files/tow-time2013.pdf The ublox-6T performs at least as well as the M12+T does. They are both in the 1 to 2 ns/day ballpark. The advantage is that the 6T is a production part and the M12+T and M12M are no longer made. So that's why commercial users have been forced away from the Motorola or iLotus parts. But amateurs still grab any M12 they can find because they are so good, and now dirt cheap on the surplus market. Note that Rick Hambly created the (Synergy) SSR-6T, which is a ublox-6T on a M12+T compatible PCB. Using a PIC it transparently translates between motorola and ublox binary so that the board is h/w and s/w compatible with any M12+T; a drop-in replacement. The plots you see in that PDF are the result of comparing M12+T and ublox-6T for this project. See also: http://www.gpstime.com/files/PTTI/Low_cost_GPS-based_time_and_frequency_products.pdf The bottom line is if you're looking for a low-budget but very high-performance GPS timing receiver, the M12+T is still a favorite among amateurs. If you're looking for something more modern, or a GPS timing receiver to use in quantity, or want an architecture that does or will accommodate Galileo and GLONASS, and are willing to pay the higher price, then check out the ublox-6T. /tvb - Original Message - From: Chris Albertson albertson.ch...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, April 26, 2014 10:36 PM Subject: Re: [time-nuts] New timing receivers? How does the u-bloc's performance compare to the M12+T?One of these is on my list of things to buy someday. I thought the M12+T had a 1-sigma error in the single digit nanoseconds.The u-bloc is newer it is even better? ___ 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] New timing receivers?
Hi There are an enormous lot of variables when you do all of this. You also need to figure out what you are really looking for. Often that relates to system specs. A WAAS enabled receiver will probably give you a better fast survey than a simple receiver. Are you doing a 48 hour survey or a 1 hour survey? Do you care about UTC offset? Are you just looking at second to second deltas? Are you comparing an ensemble of like receivers to each other? How good is your reference at various offsets? How good is your sky view? How nasty is the space weather this week / month? What kind of antenna are you using? Is it impacted by weather? What about outlier data / “freak out’s”? How good is your indoor weather ? (temperature etc in your lab) Lots of variables. That’s nowhere near a complete list … The issue is not - don’t even try to test it. The issue is that testing takes more than just a little bit of time. Bob On Apr 27, 2014, at 9:44 AM, Tom Van Baak t...@leapsecond.com wrote: For a nice comparison of the M12+T, M12M, and ublox-6T, start with page 34, and especially note the ADEV plot on page 40: http://www.cnssys.com/files/tow-time2013.pdf The ublox-6T performs at least as well as the M12+T does. They are both in the 1 to 2 ns/day ballpark. The advantage is that the 6T is a production part and the M12+T and M12M are no longer made. So that's why commercial users have been forced away from the Motorola or iLotus parts. But amateurs still grab any M12 they can find because they are so good, and now dirt cheap on the surplus market. Note that Rick Hambly created the (Synergy) SSR-6T, which is a ublox-6T on a M12+T compatible PCB. Using a PIC it transparently translates between motorola and ublox binary so that the board is h/w and s/w compatible with any M12+T; a drop-in replacement. The plots you see in that PDF are the result of comparing M12+T and ublox-6T for this project. See also: http://www.gpstime.com/files/PTTI/Low_cost_GPS-based_time_and_frequency_products.pdf The bottom line is if you're looking for a low-budget but very high-performance GPS timing receiver, the M12+T is still a favorite among amateurs. If you're looking for something more modern, or a GPS timing receiver to use in quantity, or want an architecture that does or will accommodate Galileo and GLONASS, and are willing to pay the higher price, then check out the ublox-6T. /tvb - Original Message - From: Chris Albertson albertson.ch...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, April 26, 2014 10:36 PM Subject: Re: [time-nuts] New timing receivers? How does the u-bloc's performance compare to the M12+T?One of these is on my list of things to buy someday. I thought the M12+T had a 1-sigma error in the single digit nanoseconds.The u-bloc is newer it is even better? ___ 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] New timing receivers?
Tom, There is an important error in your message below. The Motorola designed M12M receiver is still in popular and in full production mode. You can get them from Synergy Systems, LLC in San Diego. They are very friendly to time-nuts members. The M12M has been used continuously by commercial companies in the timing community since iLotus took over production from Motorola in 2006. The timing characteristics of the M12M are basically the same as the Motorola M12+ but the M12M has a wider input gain range (10 to 50 dB) and a faster Time To First Fix (TTFF) and it continues to be available from stock. Synergy also has the SSR-6T series of receivers that have a uBlox module but emulate the M12M commands and messages. These are plug in replacements for the M12M. The emulation is not total but has most of what you need from the M12M command set. These boards support some additional commands including one that puts the receiver in uBlox binary message mode at 9600 baud. These boards are very useful to those wanting the improved performance of the uBlox modules but do not want to rewrite all their application software. They are also useful for those migrating from the Motorola world to the uBlox world but don't want to do it all at once. Finally, Synergy has the SSR-6Tru which is a uBlox receiver on a PC board that is the same size as the M12M and plugs into an M12M slot but communicates only in uBlox's binary language at all baud rates supported by the uBlox module. Rick W2GPS -Original Message- From: Tom Van Baak [mailto:t...@leapsecond.com] Sent: Sunday, April 27, 2014 9:45 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] New timing receivers? For a nice comparison of the M12+T, M12M, and ublox-6T, start with page 34, and especially note the ADEV plot on page 40: http://www.cnssys.com/files/tow-time2013.pdf The ublox-6T performs at least as well as the M12+T does. They are both in the 1 to 2 ns/day ballpark. The advantage is that the 6T is a production part and the M12+T and M12M are no longer made. So that's why commercial users have been forced away from the Motorola or iLotus parts. But amateurs still grab any M12 they can find because they are so good, and now dirt cheap on the surplus market. Note that Rick Hambly created the (Synergy) SSR-6T, which is a ublox-6T on a M12+T compatible PCB. Using a PIC it transparently translates between motorola and ublox binary so that the board is h/w and s/w compatible with any M12+T; a drop-in replacement. The plots you see in that PDF are the result of comparing M12+T and ublox-6T for this project. See also: http://www.gpstime.com/files/PTTI/Low_cost_GPS-based_time_and_frequency_prod ucts.pdf The bottom line is if you're looking for a low-budget but very high-performance GPS timing receiver, the M12+T is still a favorite among amateurs. If you're looking for something more modern, or a GPS timing receiver to use in quantity, or want an architecture that does or will accommodate Galileo and GLONASS, and are willing to pay the higher price, then check out the ublox-6T. /tvb ___ 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] New timing receivers?
Hi Rick, Thanks very much for the correction, and for the additional information. Glad to hear the M12M is still around. That's good news for all of us. But then can you explain what you meant in your PTTI paper when you said: Anticipating the need for a M-12 replacement, Synergy examined the uBlox LEA-6T receiver. Because of the large installed base of Motorola and iLotus receivers, a hybrid M-12 emulator was developed http://www.gpstime.com/files/PTTI/Low_cost_GPS-based_time_and_frequency_products.pdf Thanks, /tvb - Original Message - From: W2GPS w2...@cnssys.com To: 'Tom Van Baak' t...@leapsecond.com; 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Sunday, April 27, 2014 1:10 PM Subject: RE: [time-nuts] New timing receivers? Tom, There is an important error in your message below. The Motorola designed M12M receiver is still in popular and in full production mode. You can get them from Synergy Systems, LLC in San Diego. They are very friendly to time-nuts members. The M12M has been used continuously by commercial companies in the timing community since iLotus took over production from Motorola in 2006. The timing characteristics of the M12M are basically the same as the Motorola M12+ but the M12M has a wider input gain range (10 to 50 dB) and a faster Time To First Fix (TTFF) and it continues to be available from stock. Synergy also has the SSR-6T series of receivers that have a uBlox module but emulate the M12M commands and messages. These are plug in replacements for the M12M. The emulation is not total but has most of what you need from the M12M command set. These boards support some additional commands including one that puts the receiver in uBlox binary message mode at 9600 baud. These boards are very useful to those wanting the improved performance of the uBlox modules but do not want to rewrite all their application software. They are also useful for those migrating from the Motorola world to the uBlox world but don't want to do it all at once. Finally, Synergy has the SSR-6Tru which is a uBlox receiver on a PC board that is the same size as the M12M and plugs into an M12M slot but communicates only in uBlox's binary language at all baud rates supported by the uBlox module. Rick W2GPS -Original Message- From: Tom Van Baak [mailto:t...@leapsecond.com] Sent: Sunday, April 27, 2014 9:45 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] New timing receivers? For a nice comparison of the M12+T, M12M, and ublox-6T, start with page 34, and especially note the ADEV plot on page 40: http://www.cnssys.com/files/tow-time2013.pdf The ublox-6T performs at least as well as the M12+T does. They are both in the 1 to 2 ns/day ballpark. The advantage is that the 6T is a production part and the M12+T and M12M are no longer made. So that's why commercial users have been forced away from the Motorola or iLotus parts. But amateurs still grab any M12 they can find because they are so good, and now dirt cheap on the surplus market. Note that Rick Hambly created the (Synergy) SSR-6T, which is a ublox-6T on a M12+T compatible PCB. Using a PIC it transparently translates between motorola and ublox binary so that the board is h/w and s/w compatible with any M12+T; a drop-in replacement. The plots you see in that PDF are the result of comparing M12+T and ublox-6T for this project. See also: http://www.gpstime.com/files/PTTI/Low_cost_GPS-based_time_and_frequency_prod ucts.pdf The bottom line is if you're looking for a low-budget but very high-performance GPS timing receiver, the M12+T is still a favorite among amateurs. If you're looking for something more modern, or a GPS timing receiver to use in quantity, or want an architecture that does or will accommodate Galileo and GLONASS, and are willing to pay the higher price, then check out the ublox-6T. /tvb ___ 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] New timing receivers?
Tom, When Motorola decided to get out of the GPS business there was uncertainty about the future of the products that relied on the M12+ so a market opportunity presented itself and the SSR-6T series receivers were born. In the meantime the confusion over the future of the M12M was resolved and the product line was rescued by iLotus. Fortunately for Synergy they are the distributor for both products. Rick W2GPS -Original Message- From: Tom Van Baak [mailto:t...@leapsecond.com] Sent: Sunday, April 27, 2014 6:12 PM To: 'Discussion of precise time and frequency measurement' Cc: W2GPS Subject: Re: [time-nuts] New timing receivers? Hi Rick, Thanks very much for the correction, and for the additional information. Glad to hear the M12M is still around. That's good news for all of us. But then can you explain what you meant in your PTTI paper when you said: Anticipating the need for a M-12 replacement, Synergy examined the uBlox LEA-6T receiver. Because of the large installed base of Motorola and iLotus receivers, a hybrid M-12 emulator was developed http://www.gpstime.com/files/PTTI/Low_cost_GPS-based_time_and_frequency_prod ucts.pdf Thanks, /tvb - Original Message - From: W2GPS w2...@cnssys.com To: 'Tom Van Baak' t...@leapsecond.com; 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Sunday, April 27, 2014 1:10 PM Subject: RE: [time-nuts] New timing receivers? Tom, There is an important error in your message below. The Motorola designed M12M receiver is still in popular and in full production mode. You can get them from Synergy Systems, LLC in San Diego. They are very friendly to time-nuts members. The M12M has been used continuously by commercial companies in the timing community since iLotus took over production from Motorola in 2006. The timing characteristics of the M12M are basically the same as the Motorola M12+ but the M12M has a wider input gain range (10 to 50 dB) and a faster Time To First Fix (TTFF) and it continues to be available from stock. Synergy also has the SSR-6T series of receivers that have a uBlox module but emulate the M12M commands and messages. These are plug in replacements for the M12M. The emulation is not total but has most of what you need from the M12M command set. These boards support some additional commands including one that puts the receiver in uBlox binary message mode at 9600 baud. These boards are very useful to those wanting the improved performance of the uBlox modules but do not want to rewrite all their application software. They are also useful for those migrating from the Motorola world to the uBlox world but don't want to do it all at once. Finally, Synergy has the SSR-6Tru which is a uBlox receiver on a PC board that is the same size as the M12M and plugs into an M12M slot but communicates only in uBlox's binary language at all baud rates supported by the uBlox module. Rick W2GPS -Original Message- From: Tom Van Baak [mailto:t...@leapsecond.com] Sent: Sunday, April 27, 2014 9:45 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] New timing receivers? For a nice comparison of the M12+T, M12M, and ublox-6T, start with page 34, and especially note the ADEV plot on page 40: http://www.cnssys.com/files/tow-time2013.pdf The ublox-6T performs at least as well as the M12+T does. They are both in the 1 to 2 ns/day ballpark. The advantage is that the 6T is a production part and the M12+T and M12M are no longer made. So that's why commercial users have been forced away from the Motorola or iLotus parts. But amateurs still grab any M12 they can find because they are so good, and now dirt cheap on the surplus market. Note that Rick Hambly created the (Synergy) SSR-6T, which is a ublox-6T on a M12+T compatible PCB. Using a PIC it transparently translates between motorola and ublox binary so that the board is h/w and s/w compatible with any M12+T; a drop-in replacement. The plots you see in that PDF are the result of comparing M12+T and ublox-6T for this project. See also: http://www.gpstime.com/files/PTTI/Low_cost_GPS-based_time_and_frequency_prod ucts.pdf The bottom line is if you're looking for a low-budget but very high-performance GPS timing receiver, the M12+T is still a favorite among amateurs. If you're looking for something more modern, or a GPS timing receiver to use in quantity, or want an architecture that does or will accommodate Galileo and GLONASS, and are willing to pay the higher price, then check out the ublox-6T. /tvb ___ 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] New timing receivers?
I spent some time reading the uBlox-6 documentation. I found the TIM-TP ubx message and format. I see that there is also the ability to feed back to the uBlox-6 time shift info for the PPS in 1ns increments. Does it make sense to feed the TIM-TP info back this way to provide correction? Or is an external delay line or TIC plus software the only way? Thanks jim ab3cv On Sat, Apr 26, 2014 at 7:59 PM, Jim Miller j...@jtmiller.com wrote: I'm reading though the manual for my recently acquired M12+T which I'm looking forward to using. I notice that the manual is dated 09FEB05. So the M12+T has been around for about a decade. Are there more recent timing receivers available now or has the ubiquity of the consumer GPS market distracted all investment from timing receivers except at the high end? Thanks Jim AB3CV ___ 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] New timing receivers?
Jim, Most (all?) timing receivers allow you to virtually shift the 1PPS forwards and backwards to compensate for antenna delay or other factors. But the physical 1PPS output will still have clock quantization and the only way to deal with this is external h/w or s/w sawtooth correction. Imagine some GPS timing receiver with 50 MHz clock and 20 ns quantization. Each 1PPS is one of those 50 MHz clock edges. The sawtooth correction is some number between +/- 10 ns. If you were to add 1 ns to the antenna delay, the 1PPS output would still be one of those clock edges, but the sawtooth correction number would now be 1 ns less. So there is no electrical or mathematical advantage in doing this. Speaking of which, has anyone watched what happens if you change the antenna delay by 2000, 200, 20, or 2 ns in a TBolt GPSDO? /tvb - Original Message - From: Jim Miller j...@jtmiller.com To: time-nuts time-nuts@febo.com Sent: Sunday, April 27, 2014 8:05 PM Subject: Re: [time-nuts] New timing receivers? I spent some time reading the uBlox-6 documentation. I found the TIM-TP ubx message and format. I see that there is also the ability to feed back to the uBlox-6 time shift info for the PPS in 1ns increments. Does it make sense to feed the TIM-TP info back this way to provide correction? Or is an external delay line or TIC plus software the only way? Thanks jim ab3cv On Sat, Apr 26, 2014 at 7:59 PM, Jim Miller j...@jtmiller.com wrote: I'm reading though the manual for my recently acquired M12+T which I'm looking forward to using. I notice that the manual is dated 09FEB05. So the M12+T has been around for about a decade. Are there more recent timing receivers available now or has the ubiquity of the consumer GPS market distracted all investment from timing receivers except at the high end? Thanks Jim AB3CV ___ 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] New timing receivers?
On Sun, Apr 27, 2014 at 2:14 AM, Poul-Henning Kamp p...@phk.freebsd.dkwrote Position Hold is what makes a GPS receiver timing, the sawtooth correction is icing on the cake. I've been curious about this for a while: SkyNav says the SKG16 (based on the MT3329) has a timing accuracy of 60ns rms. Sure says 20ns. TVB measured 20ns with 60ns p-p sawtooth. GlobalTop says the FGPMMOPA6H (based on the MT3339) used in the previously mentioned AdaFruit break-out has a PPS with 10ns jitter(?). u-blox says 30ns or 15ns with sawtooth correction. In the 2011 edition of TomRick (the slide has gone missing in the 2013 edition*) they show the LEA-6T at 20ns uncorrected and ~5ns corrected. Trimble says 15ns rms for the SMT. So I wonder if the MTK units are doing fixed position timing, if these numbers have not relationship to each other or if it's not that important. *btw, that's where they say Even if (/when?) the Motorola/iLotus M12’s become unavailable, the uBlox LEA6T can step in as a replacement ___ 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] New timing receivers?
j...@jtmiller.com said: I spent some time reading the uBlox-6 documentation. I found the TIM-TP ubx message and format. I see that there is also the ability to feed back to the uBlox-6 time shift info for the PPS in 1ns increments. Does it make sense to feed the TIM-TP info back this way to provide correction? (I'm reading between the lines, so this may be totally wrong.) The uBlox-6 has a free running osc. If it wasn't free running, it would be a GPSDO. There is an adjustment for antenna cable length. If you tweak the antenna length adjustment, you can make the sawtooth offset be 0 at any particular sample. But then the osc will drift and the sawtooth will tell you how much it has drifted. Or is an external delay line or TIC plus software the only way? If it was as simple as you would like, the uBlox guys would have done it already. -- These are my opinions. I hate spam. ___ 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] New timing receivers?
When I was playing with an Adafruit GPS, it appeared that if it thought you were not moving it would go into a pseudo-position-hold mode and the output coords would not change. It took it a while to start outputting new coords when you started moving again. This test was at walking speeds. I had to walk maybe 100 feet before it started sending new coords. I assume it is actually producing fixes, but not changing the output sentences (i.e so that a car stopped at a traffic light does not show it moving randomly around the intersection). ___ 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] New timing receivers?
I'm reading though the manual for my recently acquired M12+T which I'm looking forward to using. I notice that the manual is dated 09FEB05. So the M12+T has been around for about a decade. Are there more recent timing receivers available now or has the ubiquity of the consumer GPS market distracted all investment from timing receivers except at the high end? Thanks Jim AB3CV ___ 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] New timing receivers?
Hi There are a number of timing receivers on the market. They still are a very small percentage of the total units sold. A lot of people play with the uBlox parts. Bob On Apr 26, 2014, at 7:59 PM, Jim Miller j...@jtmiller.com wrote: I'm reading though the manual for my recently acquired M12+T which I'm looking forward to using. I notice that the manual is dated 09FEB05. So the M12+T has been around for about a decade. Are there more recent timing receivers available now or has the ubiquity of the consumer GPS market distracted all investment from timing receivers except at the high end? Thanks Jim AB3CV ___ 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] New timing receivers?
Have a look for Navsync CW12-TIM. We'll be using these for various timing applications including a simulcast radio repeater system over IP. They're about US$89 from SemiconductorStore.com. Many thanks! On Sun, Apr 27, 2014 at 9:59 AM, Jim Miller j...@jtmiller.com wrote: I'm reading though the manual for my recently acquired M12+T which I'm looking forward to using. I notice that the manual is dated 09FEB05. So the M12+T has been around for about a decade. Are there more recent timing receivers available now or has the ubiquity of the consumer GPS market distracted all investment from timing receivers except at the high end? Thanks Jim AB3CV ___ 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] New timing receivers?
Given the state of the GPS chip, would it really take that big an investment to just add in the firmware to do timing? Or have the manufacturers just made a marketing decision to keep that a high end market as long as they can? Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, April 26, 2014 7:27 PM Subject: Re: [time-nuts] New timing receivers? Hi There are a number of timing receivers on the market. They still are a very small percentage of the total units sold. A lot of people play with the uBlox parts. 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.
Re: [time-nuts] New timing receivers?
Hi The ratios are pretty staggering. The timing market is 1% of the total chip market. Any mass market is *always* about price. If timing adds a few percent to the mass market parts, there’s no way anybody will do it. Bob On Apr 26, 2014, at 8:37 PM, Bob Stewart b...@evoria.net wrote: Given the state of the GPS chip, would it really take that big an investment to just add in the firmware to do timing? Or have the manufacturers just made a marketing decision to keep that a high end market as long as they can? Bob From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, April 26, 2014 7:27 PM Subject: Re: [time-nuts] New timing receivers? Hi There are a number of timing receivers on the market. They still are a very small percentage of the total units sold. A lot of people play with the uBlox parts. 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] New timing receivers?
And quite a few companies use them. In a message dated 4/26/2014 8:27:57 P.M. Eastern Daylight Time, li...@rtty.us writes: Hi There are a number of timing receivers on the market. They still are a very small percentage of the total units sold. A lot of people play with the uBlox parts. Bob On Apr 26, 2014, at 7:59 PM, Jim Miller j...@jtmiller.com wrote: I'm reading though the manual for my recently acquired M12+T which I'm looking forward to using. I notice that the manual is dated 09FEB05. So the M12+T has been around for about a decade. Are there more recent timing receivers available now or has the ubiquity of the consumer GPS market distracted all investment from timing receivers except at the high end? Thanks Jim AB3CV ___ 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. ___ 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] New timing receivers?
On Sat, Apr 26, 2014 at 7:59 PM, Jim Miller j...@jtmiller.com wrote: Are there more recent timing receivers available now Yes. Google gps timing receiver for a start. Sawtooth (quantization) correction is probably the defining characteristic. So even though u-Blox makes 'T' versions (e.g. LEA-6T) they have non-T versions (e.g. NEO-6M) that provide quant. correction. Position hold / Survey In/ etc. is also a timing receiver characteristic. ___ 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] New timing receivers?
How does the u-bloc's performance compare to the M12+T?One of these is on my list of things to buy someday. I thought the M12+T had a 1-sigma error in the single digit nanoseconds.The u-bloc is newer it is even better? On Sat, Apr 26, 2014 at 6:02 PM, Paul tic-...@bodosom.net wrote: On Sat, Apr 26, 2014 at 7:59 PM, Jim Miller j...@jtmiller.com wrote: Are there more recent timing receivers available now Yes. Google gps timing receiver for a start. Sawtooth (quantization) correction is probably the defining characteristic. So even though u-Blox makes 'T' versions (e.g. LEA-6T) they have non-T versions (e.g. NEO-6M) that provide quant. correction. Position hold / Survey In/ etc. is also a timing receiver characteristic. ___ 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. -- Chris Albertson Redondo Beach, California ___ 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] new timing receivers
On Wed, April 26, 2006 21:30, Brooke Clarke said: Hi: Does anyone know about the new u-blox LEA-4T Timing GPS receiver and time stamp? http://www.u-blox.com/products/lea_4t.html I have not seen any reviews on the resolution-T derivates that are relative new. Trimble have a new Acutime version based on the Res-T technology. I have also glanced on a datasheet for a Res-T board with an OCXO, called Mini-T Thunderbolt. Wonder why its not on their timing page [1], since they claimed to be shipping it back in October 2005? [2] Anyone busy in their time-lab measuring on these units? [1] http://www.trimble.com/timing.shtml [2] http://www.trimble.com/news/100505a.shtm -- Björn ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
