Re: [time-nuts] Survey plot as art.
On Sun, Jan 15, 2017 at 6:23 AM, Andrew Rodlandwrote: > Relatedly, and just for fun, here's a video I made several years ago > from a few days worth of constellation status data out of a cheap SiRF > receiver. It's interesting to see how the satellite geometry changes > over time... or maybe it's just fun to watch the pretty colors. If > you're observant you can also get an idea for where the tall trees > were at my old apartment and maybe my approximate latitude. > > The projection is stereographic from the nadir (I think), with 90° > elevation at the center, 0° elevation at the edges, and north up. The > "wiggles" near the edges are due to the granularity of the positions > from the receiver (half-degree, IIRC). Points are drawn with size and > brightness proportional to the log signal strength, and the trails > fade out exponentially. > And here is the actual video: https://www.youtube.com/watch?v=VZHK1c54YRk -- sorry about the suspense. Andrew ___ 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] Survey plot as art.
On Sat, Jan 7, 2017 at 12:54 PM, Peter Reilleywrote: > > This is the survey from my Trimble NTBW50AA. It looks like some bacteria > floating around. Relatedly, and just for fun, here's a video I made several years ago from a few days worth of constellation status data out of a cheap SiRF receiver. It's interesting to see how the satellite geometry changes over time... or maybe it's just fun to watch the pretty colors. If you're observant you can also get an idea for where the tall trees were at my old apartment and maybe my approximate latitude. The projection is stereographic from the nadir (I think), with 90° elevation at the center, 0° elevation at the edges, and north up. The "wiggles" near the edges are due to the granularity of the positions from the receiver (half-degree, IIRC). Points are drawn with size and brightness proportional to the log signal strength, and the trails fade out exponentially. Andrew ___ 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] Survey plot as art.
I realize that, in theory, the designs for these things are relatively straightforward. Unfortunately, the *vast* majority of my experience is in the digital world, so the best I could probably do on my own is Frankenstein some hopefully-appropriate circuits together and hope the result is usable. ...that's a bit too luck-based for my tastes, so I was hoping someone had already put something appropriate together that I could just lay out and build. I'm actually a bit surprised that (apparently) nobody on this list has done so, given how many GPSs we all must collectively own... (...anybody want to? I'll fund the PCB & components for you to test your design...) -j The standard design is pretty simple: 1) DC bias coupler on the input 2) Protection on the input 3) Saw filter on the input (say -3 db) 4) Fairly normal (Mini Circuits) low noise amp with appropriate gain (say 12 to 18 db) 5) two way splitter for the two banks of outputs (-3db) 6) two way splitter to each output (-3db) (obviously a 4 output device) 7) 3 db (to 9 db) pads on each output 8) DC blocks on all but one output. 9) DC bias coupler on the one “magic” output. Some designs put a second filter after the amp. Some designs use ceramic filters rather than SAW’s. Some designs go up to quite a few (like a dozen) outputs. Some have external power rather than the bias pickoff / pass thru. ___ 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] Survey plot as art.
This might be of use/interest for a GPS distribution amplifier: http://huprf.com/huprf/wp-content/uploads/2016/03/DA1-4-Manual-V2_03.pdf On 09/01/2017 23:27, Bob kb8tq wrote: > Hi > > >> On Jan 9, 2017, at 6:06 PM, Jay Grizzard>> wrote: >> >> Does anyone know of any schematics for amplified GPS splitters floating >> around out there? I looked a while back and couldn't find anything. I use a >> 58536A right now, but it's big and I hate having to have N to SMA cables. >> It would be awesome to be able to roll my own with all the connectors I want >> on it… > The standard design is pretty simple: > > 1) DC bias coupler on the input > 2) Protection on the input > 3) Saw filter on the input (say -3 db) > 4) Fairly normal (Mini Circuits) low noise amp with appropriate gain (say 12 > to 18 db) > 5) two way splitter for the two banks of outputs (-3db) > 6) two way splitter to each output (-3db) > (obviously a 4 output device) > 7) 3 db (to 9 db) pads on each output > 8) DC blocks on all but one output. > 9) DC bias coupler on the one “magic” output. > > Some designs put a second filter after the amp. Some designs use ceramic > filters rather than SAW’s. > Some designs go up to quite a few (like a dozen) outputs. Some have external > power rather than > the bias pickoff / pass thru. > > Bob > >> -j >> >> On 1/9/2017 12:43 PM, Hal Murray wrote: >>> The other is a "real" GPS splitter such as the HP.Symmetricom 58535A or >>> 58536A. They usually have N connectors. They usually include an amplifier >>> so you don't see the 3 dB loss. (They get power from the coax the same way >>> the antenna does.) >>> >> ___ >> 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. > -- Stephen Tompsett ___ 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] Survey plot as art.
Yo Tom! On Mon, 9 Jan 2017 16:37:27 -0800 "Tom Van Baak"wrote: > Your ADEV plots differ from mine by orders of magnitude. You are right, my ADEV plots are junk. Removed. It was the 24 hour scatter plots that I wanted you to look at. Hard to argue with lat/lon data as reported by the device. You can also checkout the TDOPs which are better on the MAX-M8N > Remember > this is time-nuts, not an NTP or a GPSD forum. The Adafruit GPS board > is fine, even fantastic. But I suspect there are issues with your > measurement techniques. Hard for me to accept your relative opinion of two devices when you have never played with one of them. Whatever my techniques may be, I have side-by-side concurrent data for many GPS. Hopefully any systematic errors cancel out in the comparisons. And anyone can run, maybe even improve, the FOSS programs I'm using for comparison as well. But I agree, moving off topic for time-nuts. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgp50DZI7wYyb.pgp Description: OpenPGP digital signature ___ 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] Survey plot as art.
Hi Gary, Your ADEV plots differ from mine by orders of magnitude. Remember this is time-nuts, not an NTP or a GPSD forum. The Adafruit GPS board is fine, even fantastic. But I suspect there are issues with your measurement techniques. I'm happy to help, but let's take this off-list. 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] Survey plot as art.
Hi > On Jan 9, 2017, at 6:06 PM, Jay Grizzardwrote: > > Does anyone know of any schematics for amplified GPS splitters floating > around out there? I looked a while back and couldn't find anything. I use a > 58536A right now, but it's big and I hate having to have N to SMA cables. It > would be awesome to be able to roll my own with all the connectors I want on > it… The standard design is pretty simple: 1) DC bias coupler on the input 2) Protection on the input 3) Saw filter on the input (say -3 db) 4) Fairly normal (Mini Circuits) low noise amp with appropriate gain (say 12 to 18 db) 5) two way splitter for the two banks of outputs (-3db) 6) two way splitter to each output (-3db) (obviously a 4 output device) 7) 3 db (to 9 db) pads on each output 8) DC blocks on all but one output. 9) DC bias coupler on the one “magic” output. Some designs put a second filter after the amp. Some designs use ceramic filters rather than SAW’s. Some designs go up to quite a few (like a dozen) outputs. Some have external power rather than the bias pickoff / pass thru. Bob > > -j > > On 1/9/2017 12:43 PM, Hal Murray wrote: >> The other is a "real" GPS splitter such as the HP.Symmetricom 58535A or >> 58536A. They usually have N connectors. They usually include an amplifier >> so you don't see the 3 dB loss. (They get power from the coax the same way >> the antenna does.) >> > > ___ > 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] Survey plot as art.
Does anyone know of any schematics for amplified GPS splitters floating around out there? I looked a while back and couldn't find anything. I use a 58536A right now, but it's big and I hate having to have N to SMA cables. It would be awesome to be able to roll my own with all the connectors I want on it... -j On 1/9/2017 12:43 PM, Hal Murray wrote: The other is a "real" GPS splitter such as the HP.Symmetricom 58535A or 58536A. They usually have N connectors. They usually include an amplifier so you don't see the 3 dB loss. (They get power from the coax the same way the antenna does.) ___ 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] Survey plot as art.
Yo Tom! On Mon, 9 Jan 2017 14:01:18 -0800 "Tom Van Baak"wrote: > Hi Gary, > > > Clearly the Adafruit is not high accuracy. I have played with some > > short baseline DGPS (cm level data) and not found any issue with > > antenn separation. > > I'm surprised by your claim. My measurements show that the Adafruit > is a wonderful GPS receiver. Yes, I also find the Adafruit wonderful. It was my favorite GPS when I got it. I just find that the Uputronics GPS HAT is even better, for the same price. Compare these two pages, the first the Adafruit, the second an Uputronics Version 2. Sitting right next to each other, both iwth matching GPS antennas.: https://pi2.rellim.com/day/ https://pi4.rellim.com/day/ Especially check out the scatter plots. The number of sats received, and the DOPs, are consistently better on the Uputronics. > Attached are ADEV MDEV TDEV plots of 5 > different GPS/1PPS receivers. The raw data is from: > > http://www.leapsecond.com/pages/gpsdo-sim/ What? No pretty graphs? :-) > The Adafruit "Ultimate GPS" (MTK3339 chipset) does very well. It's > also cheap, has a built-in antenna, has a uFL connector for optional > external antenna, runs in 3D so you can use it mobile or fixed, you > don't have to bother with survey or sawtooth correction. The data you > see above is out-of-the-box; you give it 5V and out comes a 1PPS: I find the Adafruit works better for me indoors with an external antenna. I find the uFL a pain for lab use. The Uputronics have no internal antenna and an SMA connector. Plus it has a u-Blox 8. But, to be fair, both are far beyond any practical needs I have. YMMV. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpDaUHomVCuK.pgp Description: OpenPGP digital signature ___ 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] Survey plot as art.
Hi Gary, > Clearly the Adafruit is not high accuracy. I have played with some > short baseline DGPS (cm level data) and not found any issue with antenn > separation. I'm surprised by your claim. My measurements show that the Adafruit is a wonderful GPS receiver. Attached are ADEV MDEV TDEV plots of 5 different GPS/1PPS receivers. The raw data is from: http://www.leapsecond.com/pages/gpsdo-sim/ The Adafruit "Ultimate GPS" (MTK3339 chipset) does very well. It's also cheap, has a built-in antenna, has a uFL connector for optional external antenna, runs in 3D so you can use it mobile or fixed, you don't have to bother with survey or sawtooth correction. The data you see above is out-of-the-box; you give it 5V and out comes a 1PPS: https://www.adafruit.com/product/746 /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] Survey plot as art.
g...@rellim.com said: > Care to recommend any that have SMA connectors? I have found that a 3dB > difference in antenna can degrade my data quality, it would be interesting > to see how the 3dB loss of the splitter affects thins. There are 2 options for splitters. One is to use cable-TV splitters. They probably have F connectors so you will need a kludge of adapters. The other is a "real" GPS splitter such as the HP.Symmetricom 58535A or 58536A. They usually have N connectors. They usually include an amplifier so you don't see the 3 dB loss. (They get power from the coax the same way the antenna does.) -- 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.
Re: [time-nuts] Survey plot as art.
Hi Gary, >> >> My gut reaction is that "coupling" between the two antennas may >> >> have some effect on some of the variation. >> >> For high accuracy applications, I have been given the advice to keep >> GPS antenna separation much higher. 1 meter separation was suggested. > > Clearly the Adafruit is not high accuracy. I have played with some > short baseline DGPS (cm level data) and not found any issue with antenna > separation. Good for you! Others have found issues. >> For comparing GPS receiver behavior its a cleaner setup to use a GPS >> signal splitter (or basic RF splitter with suitable DC-blocks). > > Care to recommend any that have SMA connectors? I have found that > a 3dB difference in antenna can degrade my data quality, it would be > interesting to see how the 3dB loss of the splitter affects thins. The ZAPD-2DC+ from Minicircuits are good value for money, if 2 ports are enough. The Colorado based "GPS Source" and "GPS Networking" both provide quality products. They have versions with SMA, but also TNC or N. Splitters build for GPS use can be passive, but they are often amplified. They will also pass power up to the lna in the antenna. -- Björn http://194.75.38.69/pdfs/ZAPD-2DC+.pdf https://www.gpsnetworking.com/store https://www.gpssource.com/products/s18s-1x8-slimline-gps-splitter ___ 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] Survey plot as art.
Yo Björn! On Mon, 9 Jan 2017 07:45:00 +0100 "Björn Gabrielsson"wrote: > >> My gut reaction is that "coupling" between the two antennas may > >> have some effect on some of the variation. > > For high accuracy applications, I have been given the advice to keep > GPS antenna separation much higher. 1 meter separation was suggested. Clearly the Adafruit is not high accuracy. I have played with some short baseline DGPS (cm level data) and not found any issue with antenna separation. > For comparing GPS receiver behavior its a cleaner setup to use a GPS > signal splitter (or basic RF splitter with suitable DC-blocks). Care to recommend any that have SMA connectors? I have found that a 3dB difference in antenna can degrade my data quality, it would be interesting to see how the 3dB loss of the splitter affects thins. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpBUF_w0vMDM.pgp Description: OpenPGP digital signature ___ 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] Survey plot as art.
Hi Gary, > Yo Artek! > > On Sun, 8 Jan 2017 17:18:06 -0500 > Artek Manualswrote: > >> Only 1" ? (1" center to center or edge to edge spacing?) > > One inch edge to edge. > >> My gut reaction is that "coupling" between the two antennas may have >> some effect on some of the variation. For high accuracy applications, I have been given the advice to keep GPS antenna separation much higher. 1 meter separation was suggested. For comparing GPS receiver behavior its a cleaner setup to use a GPS signal splitter (or basic RF splitter with suitable DC-blocks). -- 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] Survey plot as art.
Yo Hal! On Sun, 08 Jan 2017 20:41:25 -0800 Hal Murraywrote: > g...@rellim.com said: > >> The Adafruit receiver outputs NMEA format data. The lat/lon values > >> are sent as dddmm.mm format (ddd=degrees, mm.mm=minutes) This > >> restricts the resolution of the values. > > > Yes, easy to see the quantization in the Adafruit plot. > > Something doesn't look quite right. If the problem was as simple as > reduced lat/lon resolution, I'd expect the output to be on a grid. > Instead, what I see is more like a grid that was also missing 1 out > of N slots. Where is that coming from? How do I predict N? Yes, the raw data shows that it is not using all the possible precision. It does skip lat/lons that are representable. I'm almost at 45N, so that partlly explains why the lat missing codes are smaller than the lon missing codes. > I expect it's something like roundoff after the conversion from mm.mm > to meters, or something like that. No rounding happening in gpsd. That is in the raw NMEA. > Just to make sure we are on the same wavelength, this is the graph > I'm looking at. > > https://www.febo.com/pipermail/time-nuts/attachments/20170108/051ba89d/attachm > ent-0003.png Yup. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpIKSdqw2umQ.pgp Description: OpenPGP digital signature ___ 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] Survey plot as art.
g...@rellim.com said: >> The Adafruit receiver outputs NMEA format data. The lat/lon values >> are sent as dddmm.mm format (ddd=degrees, mm.mm=minutes) This >> restricts the resolution of the values. > Yes, easy to see the quantization in the Adafruit plot. Something doesn't look quite right. If the problem was as simple as reduced lat/lon resolution, I'd expect the output to be on a grid. Instead, what I see is more like a grid that was also missing 1 out of N slots. Where is that coming from? How do I predict N? I expect it's something like roundoff after the conversion from mm.mm to meters, or something like that. Just to make sure we are on the same wavelength, this is the graph I'm looking at. https://www.febo.com/pipermail/time-nuts/attachments/20170108/051ba89d/attachm ent-0003.png -- 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.
Re: [time-nuts] Survey plot as art.
Yo Mark! On Mon, 9 Jan 2017 03:41:07 + Mark Simswrote: > The Adafruit receiver outputs NMEA format data. The lat/lon values > are sent as dddmm.mm format (ddd=degrees, mm.mm=minutes) This > restricts the resolution of the values. Some receivers and newer > NMEA specs support more digits past the decimal point. Receivers > that support native binary formats that report lat/lon as 32-bit > floats show similar quantization. Yes, easy to see the quantization in the Adafruit plot. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgphIZvf8Pj9b.pgp Description: OpenPGP digital signature ___ 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] Survey plot as art.
The Adafruit receiver outputs NMEA format data. The lat/lon values are sent as dddmm.mm format (ddd=degrees, mm.mm=minutes) This restricts the resolution of the values. Some receivers and newer NMEA specs support more digits past the decimal point. Receivers that support native binary formats that report lat/lon as 32-bit floats show similar quantization. The Thunderbolt has a command for entering the receiver position, but it uses 32-bit floats. This restricts the accuracy that you can enter a position. Lady Heather's precision survey routines can calculate a position to greater accuracy. In order to save the high-accuracy calculated position it uses the rather nasty technique of doing single-point self-surveys until one happens to be within a foot or so of the calculated position that can take an indeterminate amount of time to happen, but eventually gets the job done. - > The Adafruit plot seems to have quantization. Are the values being "snapped" to a grid in any way? ___ 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] Survey plot as art.
On Mon, Jan 9, 2017 at 5:52 AM, Gary E. Millerwrote: > I just ran 24 scatter plots on 2 GPS with external antennas one inch apart. > > pi2-5.png is an Adafruit GPS HAT with an MTK-3301. upuv2.png is an > Uputronics GPS HAT version 2, with a uBlox 8. > The Adafruit plot seems to have quantization. Are the values being "snapped" to a grid in any way? -- Sanjeev Gupta +65 98551208 http://www.linkedin.com/in/ghane ___ 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] Survey plot as art.
Yo Artek! On Sun, 8 Jan 2017 17:18:06 -0500 Artek Manualswrote: > Only 1" ? (1" center to center or edge to edge spacing?) One inch edge to edge. > My gut reaction is that "coupling" between the two antennas may have > some effect on some of the variation. I have tried many various combinations over the last 6 months. using 6 diferent GPS. Before that I took some GPS to an open field. Also friends of mine have run gpsprof and gotten similar. All look pretty much like these, modulo the different GPS chips. gpsprof is part of the gpsd package, feel free to do yooou own plots. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpuRav0K7SO1.pgp Description: OpenPGP digital signature ___ 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] Survey plot as art.
Gary Only 1" ? (1" center to center or edge to edge spacing?) My gut reaction is that "coupling" between the two antennas may have some effect on some of the variation. You may in fact have unintentionally created a phased array. This phased array could favor one antenna in an particular Az/El and favor the other in another Az/El. If not too arduous it would be good to separate the antennas by several feet, run the data again then swap mountings of the antennas and run yet another set of data Dave manu...@artekmanuals.com On 1/8/2017 4:52 PM, Gary E. Miller wrote: Yo All! I just ran 24 scatter plots on 2 GPS with external antennas one inch apart. pi2-5.png is an Adafruit GPS HAT with an MTK-3301. upuv2.png is an Uputronics GPS HAT version 2, with a uBlox 8. See attached. I'm not sure it sheds any light on this discussion... There does appear to be a bit of correlation between the bigger random walks in the graphs. And a whole lot of other things going on. During that time, the Adafruit saw 6 to 12 sats and a constant TDOP of 0.82. The Uputronics reported seeing 4 to 20 sats and a TDOP from 0.42 to 32.6 and a mean of 0.786 and a SD of 0.668. To bring this back to time-nuttery, when the TDOP hit 32.6 I can see a 2 micro Second spike in NTP jitter. So for that small period in time my Raspberry Pi clock was more stable than my PPS. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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. -- Dave manu...@artekmanuals.com www.ArtekManuals.com --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ 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] Survey plot as art.
Yo All! I just ran 24 scatter plots on 2 GPS with external antennas one inch apart. pi2-5.png is an Adafruit GPS HAT with an MTK-3301. upuv2.png is an Uputronics GPS HAT version 2, with a uBlox 8. See attached. I'm not sure it sheds any light on this discussion... There does appear to be a bit of correlation between the bigger random walks in the graphs. And a whole lot of other things going on. During that time, the Adafruit saw 6 to 12 sats and a constant TDOP of 0.82. The Uputronics reported seeing 4 to 20 sats and a TDOP from 0.42 to 32.6 and a mean of 0.786 and a SD of 0.668. To bring this back to time-nuttery, when the TDOP hit 32.6 I can see a 2 micro Second spike in NTP jitter. So for that small period in time my Raspberry Pi clock was more stable than my PPS. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpEQi7T8mkHT.pgp Description: OpenPGP digital signature ___ 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] Survey plot as art.
> How do you display the survey plot in LH? i.e. the keyboard commands If your receiver is running in a non-position hold mode then GI will show the "fix map"... in position hold modes the fix map is just a single dot at the center.Or you can zoom it to full screen with the ZL command. Depending upon the version, you can also try clicking on the lat/lon/alt info. The fix map shows all positions received since the location reference point was last reset (CL command, or survey, etc started). Each hour the color of the dots changes over a 14 hour cycle. The default fix map resolution is 3 meters / 10 feet per division. You can change this with the /tm= or /t'= command line options. Issuing these from the keyboard will attempt to regenerate the fix map from plot queue data, but those are single precision floating point numbers and due to round off/loss of precision you lose a lot of detail and lower settings. Many receivers apply some sort of dynamics filtering or "position pinning" to the receiver location. This can distort the positions that the receiver is reporting and mask a lot of the effect. Generally, Heather tries to turn off position pinning. The "F" filter menu lets you control the dynamics filters on receivers that support them. Lat/lon/alt can also be shown as plots in the plot area GV toggles lat/lon/alt. Or G1 is lat, G2 is lon, G3 is alt. ___ 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] Survey plot as art.
Hi There is a *lot* of difference between how various receiver architectures respond to multipath. You can spend hours of “quality time” looking into the various claims of people having completely eliminated muitipath by this or that software trick. Bob > On Jan 7, 2017, at 4:31 PM, Peter Reilleywrote: > > In my case (the original post) there can be no multipath difference, same > antenna and done at the same time. > The length of the cables from the amplified splitter are about the same; > within inches. > This must be some difference in the receiver, perhaps in the math? > > Pete. > > On 1/7/2017 4:16 PM, Bob Camp wrote: >> Hi >> >> In terms of multipath at GPS frequencies, a couple of inches is a *lot*. >> Also unless you have >> pretty good antennas (as in much larger than 1” each) they will have phase >> issues unique >> to each antenna. Phase cancellation and addition is what gives you multipath. >> >> Bob >> >>> On Jan 7, 2017, at 4:00 PM, Gary E. Miller wrote: >>> >>> Yo Bob! >>> >>> On Sat, 7 Jan 2017 15:16:34 -0500 >>> Bob Camp wrote: >>> The “simple” answer is that the weird legs going out from the central blob are the result of multi-path / reflections in the received signal. With enough data you might be able to correlate them to observed obstructions. >>> I have lots of data from GPS with the antennas mounted 1 inch apart. >>> They show different weird legs, so I suspect that local geology/architecture >>> is not the whole story. >>> >>> For example, compare the plot I just sent, to the one attached here. >>> Two GPS right next to each other, very differently looking plots. >>> >>> I'll admit to never generating plots over the same time interval, I'll >>> start a 24 hour test of two GPS right now. >>> >>> RGDS >>> GARY >>> --- >>> Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 >>> g...@rellim.com Tel:+1 541 382 8588 >>> >>> Veritas liberabit vos. -- Quid est veritas? >>>"If you can’t measure it, you can’t improve it." - Lord Kelvin >>> ___ >>> 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. ___ 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] Survey plot as art.
Yo Hal! On Sat, 07 Jan 2017 14:16:16 -0800 Hal Murraywrote: > g...@rellim.com said: > >> In my case (the original post) there can be no multipath > >> difference, same antenna and done at the same time. > > There sure can be. The GPS birds are moving in orbit. At certain > > points in the sky their signal may be bouncing off a nearby steel > > building and into your antenna. > > He didn't say no multipath, but rather no multipath difference. He's > feeding 2 GPS units from the same antenna through a splitter. Ah. Got it. Thank you. Same model GPS? RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgp3dBeHeOtP4.pgp Description: OpenPGP digital signature ___ 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] Survey plot as art.
g...@rellim.com said: >> In my case (the original post) there can be no multipath difference, >> same antenna and done at the same time. > There sure can be. The GPS birds are moving in orbit. At certain points in > the sky their signal may be bouncing off a nearby steel building and into > your antenna. He didn't say no multipath, but rather no multipath difference. He's feeding 2 GPS units from the same antenna through a splitter. -- 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.
Re: [time-nuts] Survey plot as art.
The plots that I posted were of a 48 hour survey but only 32% of the survey had completed. When the survey completes the plot display will disappear. Pete. On 1/7/2017 4:34 PM, Bryan _ wrote: Thanks Pete, I have a Jupiter-T hooked up right now and wanted to see how the plot compares to your, unfortunately my antenna position is poor, so will be interesting. How many hours did you plot for? -=Bryan=- From: time-nuts <time-nuts-bounces+bpl521=outlook@febo.com> on behalf of Peter Reilley <preilley_...@comcast.net> Sent: January 7, 2017 1:15 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Survey plot as art. You start a precision survey with this command; sp You are offered 48 (hour) survey as an option. I think that you can go up to 96 hours. During the survey the scatter plot is displayed. Pete. On 1/7/2017 3:32 PM, Bryan _ wrote: How do you display the survey plot in LH? i.e. the keyboard commands -=Bryan=- From: time-nuts <time-nuts-boun...@febo.com> on behalf of Peter Reilley <preilley_...@comcast.net> Sent: January 7, 2017 9:54 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Survey plot as art. This is the survey from my Trimble NTBW50AA. It looks like some bacteria floating around. The curious thing are the excursions. Rather than being noise like, some follow a distinct path. But this is only over a few seconds so it seems unlikely that they are caused by weather conditions. The survey from my Resolution T taken at the same time and using the same antenna (with a splitter) shows much less orderly excursions and is more noise like. Trimble NTBW50AA survey. Resolution T survey Pete. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... www.febo.com<http://www.febo.com> American Febo Enterprises<http://www.febo.com/> www.febo.com Welcome to American Febo Enterprises! Welcome to American Febo Enterprises, a proud subsidiary of International MultiGeek. AFE is an intergalactic consultatorium ... time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... 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 time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... 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 time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... 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] Survey plot as art.
Another thought, perhaps the difference is between the quality of the oscillators. The Resolution T has an ordinary XO while the NTBW50AA has an OCXO (possibly defective). I would expect the XO to be noise like in a stable temperature environment. The OCXO, if defective, may have semi-controlled excursions from it's design frequency. However, I don't know if the 10 MHz of the OXCO is used by the GPS chip and could therefore affect the calculated position. Pete. On 1/7/2017 4:31 PM, Peter Reilley wrote: In my case (the original post) there can be no multipath difference, same antenna and done at the same time. The length of the cables from the amplified splitter are about the same; within inches. This must be some difference in the receiver, perhaps in the math? Pete. On 1/7/2017 4:16 PM, Bob Camp wrote: Hi In terms of multipath at GPS frequencies, a couple of inches is a *lot*. Also unless you have pretty good antennas (as in much larger than 1” each) they will have phase issues unique to each antenna. Phase cancellation and addition is what gives you multipath. Bob On Jan 7, 2017, at 4:00 PM, Gary E. Millerwrote: Yo Bob! On Sat, 7 Jan 2017 15:16:34 -0500 Bob Camp wrote: The “simple” answer is that the weird legs going out from the central blob are the result of multi-path / reflections in the received signal. With enough data you might be able to correlate them to observed obstructions. I have lots of data from GPS with the antennas mounted 1 inch apart. They show different weird legs, so I suspect that local geology/architecture is not the whole story. For example, compare the plot I just sent, to the one attached here. Two GPS right next to each other, very differently looking plots. I'll admit to never generating plots over the same time interval, I'll start a 24 hour test of two GPS right now. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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. ___ 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] Survey plot as art.
Yo Peter! On Sat, 7 Jan 2017 16:31:25 -0500 Peter Reilleywrote: > In my case (the original post) there can be no multipath difference, > same antenna and done at the same time. There sure can be. The GPS birds are moving in orbit. At certain points in the sky their signal may be bouncing off a nearby steel building and into your antenna. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpNm5XiRnW1p.pgp Description: OpenPGP digital signature ___ 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] Survey plot as art.
Thanks Pete, I have a Jupiter-T hooked up right now and wanted to see how the plot compares to your, unfortunately my antenna position is poor, so will be interesting. How many hours did you plot for? -=Bryan=- From: time-nuts <time-nuts-bounces+bpl521=outlook@febo.com> on behalf of Peter Reilley <preilley_...@comcast.net> Sent: January 7, 2017 1:15 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Survey plot as art. You start a precision survey with this command; sp You are offered 48 (hour) survey as an option. I think that you can go up to 96 hours. During the survey the scatter plot is displayed. Pete. On 1/7/2017 3:32 PM, Bryan _ wrote: > How do you display the survey plot in LH? i.e. the keyboard commands > > > -=Bryan=- > > > > From: time-nuts <time-nuts-boun...@febo.com> on behalf of Peter Reilley > <preilley_...@comcast.net> > Sent: January 7, 2017 9:54 AM > To: Discussion of precise time and frequency measurement > Subject: [time-nuts] Survey plot as art. > > > This is the survey from my Trimble NTBW50AA. It looks like some > bacteria floating around. > > The curious thing are the excursions. Rather than being noise like, > some follow a distinct > path. But this is only over a few seconds so it seems unlikely that > they are caused by > weather conditions. The survey from my Resolution T taken at the same > time and using > the same antenna (with a splitter) shows much less orderly excursions > and is more noise > like. > > > Trimble NTBW50AA survey. > > > Resolution T survey > > > Pete. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... > time-nuts Info Page - American Febo > Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... > www.febo.com<http://www.febo.com> American Febo Enterprises<http://www.febo.com/> www.febo.com Welcome to American Febo Enterprises! Welcome to American Febo Enterprises, a proud subsidiary of International MultiGeek. AFE is an intergalactic consultatorium ... > time-nuts is a low volume, high SNR list for the discussion of precise time > and frequency measurement and related topics. To see the collection of prior > postings to ... > > > > 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 time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... > 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 time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... 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] Survey plot as art.
In my case (the original post) there can be no multipath difference, same antenna and done at the same time. The length of the cables from the amplified splitter are about the same; within inches. This must be some difference in the receiver, perhaps in the math? Pete. On 1/7/2017 4:16 PM, Bob Camp wrote: Hi In terms of multipath at GPS frequencies, a couple of inches is a *lot*. Also unless you have pretty good antennas (as in much larger than 1” each) they will have phase issues unique to each antenna. Phase cancellation and addition is what gives you multipath. Bob On Jan 7, 2017, at 4:00 PM, Gary E. Millerwrote: Yo Bob! On Sat, 7 Jan 2017 15:16:34 -0500 Bob Camp wrote: The “simple” answer is that the weird legs going out from the central blob are the result of multi-path / reflections in the received signal. With enough data you might be able to correlate them to observed obstructions. I have lots of data from GPS with the antennas mounted 1 inch apart. They show different weird legs, so I suspect that local geology/architecture is not the whole story. For example, compare the plot I just sent, to the one attached here. Two GPS right next to each other, very differently looking plots. I'll admit to never generating plots over the same time interval, I'll start a 24 hour test of two GPS right now. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin ___ 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] Survey plot as art.
Yo Bob! On Sat, 7 Jan 2017 16:16:44 -0500 Bob Campwrote: > In terms of multipath at GPS frequencies, a couple of inches is a > *lot*. Also unless you have pretty good antennas (as in much larger > than 1” each) they will have phase issues unique to each antenna. > Phase cancellation and addition is what gives you multipath. I see up to 10x better/worse between GPS brands. Measured by CEP(). A much smaller change between antenna models. I also have interchanged antennas between my GPS to rule them out as the major contributing source to error and discard the worst ones. I just started 24 hour plots of 4 adjacent GPS. I guess tomorrow I'll rotate the antennas between GPS, witout moving the antennas, and repeat. I suspect we may be just seeing different aspects of the same thing. A big difference between GPS models is probably the quality of multipath rejection. And I can easily change my GPS, but chaning my geoplogy is a lot harder. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpYyS_YvRTlC.pgp Description: OpenPGP digital signature ___ 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] Survey plot as art.
Hi In terms of multipath at GPS frequencies, a couple of inches is a *lot*. Also unless you have pretty good antennas (as in much larger than 1” each) they will have phase issues unique to each antenna. Phase cancellation and addition is what gives you multipath. Bob > On Jan 7, 2017, at 4:00 PM, Gary E. Millerwrote: > > Yo Bob! > > On Sat, 7 Jan 2017 15:16:34 -0500 > Bob Camp wrote: > >> The “simple” answer is that the weird legs going out from the central >> blob are the result of multi-path / reflections in the received >> signal. With enough data you might be able to correlate them to >> observed obstructions. > > I have lots of data from GPS with the antennas mounted 1 inch apart. > They show different weird legs, so I suspect that local geology/architecture > is not the whole story. > > For example, compare the plot I just sent, to the one attached here. > Two GPS right next to each other, very differently looking plots. > > I'll admit to never generating plots over the same time interval, I'll > start a 24 hour test of two GPS right now. > > RGDS > GARY > --- > Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 > g...@rellim.com Tel:+1 541 382 8588 > > Veritas liberabit vos. -- Quid est veritas? >"If you can’t measure it, you can’t improve it." - Lord Kelvin > ___ > 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] Survey plot as art.
You start a precision survey with this command; sp You are offered 48 (hour) survey as an option. I think that you can go up to 96 hours. During the survey the scatter plot is displayed. Pete. On 1/7/2017 3:32 PM, Bryan _ wrote: How do you display the survey plot in LH? i.e. the keyboard commands -=Bryan=- From: time-nuts <time-nuts-boun...@febo.com> on behalf of Peter Reilley <preilley_...@comcast.net> Sent: January 7, 2017 9:54 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Survey plot as art. This is the survey from my Trimble NTBW50AA. It looks like some bacteria floating around. The curious thing are the excursions. Rather than being noise like, some follow a distinct path. But this is only over a few seconds so it seems unlikely that they are caused by weather conditions. The survey from my Resolution T taken at the same time and using the same antenna (with a splitter) shows much less orderly excursions and is more noise like. Trimble NTBW50AA survey. Resolution T survey Pete. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... 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] Survey plot as art.
Yo Bob! On Sat, 7 Jan 2017 15:16:34 -0500 Bob Campwrote: > The “simple” answer is that the weird legs going out from the central > blob are the result of multi-path / reflections in the received > signal. With enough data you might be able to correlate them to > observed obstructions. I have lots of data from GPS with the antennas mounted 1 inch apart. They show different weird legs, so I suspect that local geology/architecture is not the whole story. For example, compare the plot I just sent, to the one attached here. Two GPS right next to each other, very differently looking plots. I'll admit to never generating plots over the same time interval, I'll start a 24 hour test of two GPS right now. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpW3hGP3bDIV.pgp Description: OpenPGP digital signature ___ 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] Survey plot as art.
How do you display the survey plot in LH? i.e. the keyboard commands -=Bryan=- From: time-nuts <time-nuts-boun...@febo.com> on behalf of Peter Reilley <preilley_...@comcast.net> Sent: January 7, 2017 9:54 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Survey plot as art. This is the survey from my Trimble NTBW50AA. It looks like some bacteria floating around. The curious thing are the excursions. Rather than being noise like, some follow a distinct path. But this is only over a few seconds so it seems unlikely that they are caused by weather conditions. The survey from my Resolution T taken at the same time and using the same antenna (with a splitter) shows much less orderly excursions and is more noise like. Trimble NTBW50AA survey. Resolution T survey Pete. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... 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] Survey plot as art.
Hi The “simple” answer is that the weird legs going out from the central blob are the result of multi-path / reflections in the received signal. With enough data you might be able to correlate them to observed obstructions. The simulation modeling required to make that happen might be a bit complex….. Bob > On Jan 7, 2017, at 3:07 PM, Gary E. Millerwrote: > > Yo Peter! > > On Sat, 7 Jan 2017 12:54:45 -0500 > Peter Reilley wrote: > >> This is the survey from my Trimble NTBW50AA. It looks like some >> bacteria floating around. > > You can get those from any GPS using the program gpsprof from gpsd. > > See attached for a 24 plot from a stationary GlobalSat MR-350P > > I find these plots very useful when comparing GPS models. > > RGDS > GARY > --- > Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 > g...@rellim.com Tel:+1 541 382 8588 > > Veritas liberabit vos. -- Quid est veritas? >"If you can’t measure it, you can’t improve it." - Lord Kelvin > ___ > 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] Survey plot as art.
Yo Peter! On Sat, 7 Jan 2017 12:54:45 -0500 Peter Reilleywrote: > This is the survey from my Trimble NTBW50AA. It looks like some > bacteria floating around. You can get those from any GPS using the program gpsprof from gpsd. See attached for a 24 plot from a stationary GlobalSat MR-350P I find these plots very useful when comparing GPS models. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpPR55fTeIcf.pgp Description: OpenPGP digital signature ___ 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] Survey plot as art.
preilley_...@comcast.net said: > The curious thing are the excursions. Rather than being noise like, some > follow a distinct path. But this is only over a few seconds so it seems > unlikely that they are caused by weather conditions. ... I've seen similar quirks when a non-timing unit ran out of satellites. I assume that it switched to dead reckoning mode and the last noisy sample included some velocity. A few examples have made it to an orbit down near the south pole. It would be interesting to look at the signal quality during and just before one of your little filaments. -- 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.
Re: [time-nuts] Survey plot as art.
Try again; Pete. On 1/7/2017 12:54 PM, Peter Reilley wrote: This is the survey from my Trimble NTBW50AA. It looks like some bacteria floating around. The curious thing are the excursions. Rather than being noise like, some follow a distinct path. But this is only over a few seconds so it seems unlikely that they are caused by weather conditions. The survey from my Resolution T taken at the same time and using the same antenna (with a splitter) shows much less orderly excursions and is more noise like. Trimble NTBW50AA survey. Resolution T survey Pete. ___ 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] Survey plot as art.
This is the survey from my Trimble NTBW50AA. It looks like some bacteria floating around. The curious thing are the excursions. Rather than being noise like, some follow a distinct path. But this is only over a few seconds so it seems unlikely that they are caused by weather conditions. The survey from my Resolution T taken at the same time and using the same antenna (with a splitter) shows much less orderly excursions and is more noise like. Trimble NTBW50AA survey. Resolution T survey Pete. ___ 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.