Re: [time-nuts] tyco electronics A1025

2014-12-15 Thread Brian Inglis
On 2014-12-14 10:29, Francesco Messineo wrote: On Sun, Dec 14, 2014 at 6:12 PM, Bob Camp kb...@n1k.org wrote: that's not meant as a time nut stratum 1. It's just a free gps module I would like to recycle as a needed stratum 1 server for a small network. Of course if I can find informations on

[time-nuts] GPS position averaging

2014-12-15 Thread Ole Petter Ronningen
Hello, all I have a couple of GPSDOs (KS, z3805a) hooked up to a fixed outdoor antenna through an HP 58516 splitter. I notice that when I powercycle the GPSDOs (which I generally try to avoid), the position they come up with differs from time to time in at least the last three digits (and height

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Hal Murray
olep...@gmail.com said: My question is twofold; 1) is this for some reason a bad idea? And 2) How do I average the numbers? I can not put my finger on it but it feels wrong to average lat, long and height independently. It seems like an interesting idea to me. It would be interesting to run

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Dave Daniel
I am new to this list and to this topic, but it seems to me that if one wants to come up with an average of a set of spatial measurements, one would use distance as the parameter to be averaged. The distance would presumably be that from a fixed spatial reference point (0,0,0). One would then

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Tim Shoppa
I would recommend determining your terrain's elevation using a topo map and estimating or measuring antennas height above ground. And then excluding survey results with wacko altitudes before averaging. While we often set the elevation angle mask high for timing purposes, for survey purposes

Re: [time-nuts] The Trapezoidal Clocking

2014-12-15 Thread Bob Camp
Hi If you treat it as a sine, you certainly get further. There are some neat sine wave input chips. The next layer to the problem is that the trapezoid may be slower than (or faster than ) a sine wave depending on just what’s going on with the system. That will make it a bit difficult to know

Re: [time-nuts] Did a member of time-nuts buy this?

2014-12-15 Thread Bob Camp
On Dec 15, 2014, at 2:27 AM, Mike Monett timen...@binsamp.e4ward.com wrote: Hi On Dec 10, 2014, at 11:12 PM, Mike Monett timen...@binsamp.e4ward.com wrote: [...] Can you tell me some of the ones that do? I have yet to see one for under $2K that does it correctly. I don't have

Re: [time-nuts] tyco electronics A1025

2014-12-15 Thread Francesco Messineo
On Mon, Dec 15, 2014 at 9:09 AM, Brian Inglis brian.ing...@systematicsw.ab.ca wrote: On 2014-12-14 10:29, Francesco Messineo wrote: The A1029, which is a newer model, has indeed a PPS output and I've been able to find a datasheet for it but the pinout isn't anything like the A1025. I planned

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Azelio Boriani
The Ublox M8N can send out raw measurements with messages TRK-MEAS and TRK-SFRBX for observation and navigation data: you can postprocess them to improve the accuracy. http://www.rtklib.com/rtklib_support.htm On Mon, Dec 15, 2014 at 12:43 PM, Tim Shoppa tsho...@gmail.com wrote: I would recommend

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Paul
On Mon, Dec 15, 2014 at 10:52 AM, Azelio Boriani azelio.bori...@gmail.com wrote: The Ublox M8N can send out raw measurements with messages TRK-MEAS and TRK-SFRBX for observation and navigation data: you can postprocess them to improve the accuracy. And searching the archives for rtklib

[time-nuts] Manual repository

2014-12-15 Thread Didier Juges
Users of my web site may have had difficulties getting some of the files in the last couple of months. Particularly, those files that were recently uploaded. Typical symptom would be a file that was uploaded, was removed from the Recent Upload folder (indicating that I moved the file to it's

[time-nuts] GPS position averaging

2014-12-15 Thread Mark Sims
Take a look at the code in Lady Heather that does a 48 hour precision survey. It calculates a weighted median position of fixes over 1 hour periods then calculates a final position from those medians. The algorithm was developed by having people around the world with Thunderbolts and quality

Re: [time-nuts] tyco electronics A1025

2014-12-15 Thread Francesco Messineo
I reply to myself, On Mon, Dec 15, 2014 at 2:41 PM, Francesco Messineo francesco.messi...@gmail.com wrote: I've found a couple of articles saying the A1025 indeed has PPS output as I suspected. However, none of them reports any hint about the pinout of this module. The module itself is

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Bob Camp
Hi Simple answer - there is no simple answer. You will get significantly better results by intelligently processing the data than by a giant “average everything in sight” approach. Also consider that various GPS modules seem to have offsets in their nav solution. The NIST papers on various

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Angus
On Mon, 15 Dec 2014 17:55:20 -0500, you wrote: Hi Simple answer - there is no simple answer. You will get significantly better results by intelligently processing the data than by a giant “average everything in sight” approach. Also consider that various GPS modules seem to have offsets in

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Bob Camp
Hi On Dec 15, 2014, at 6:39 PM, Angus not.ag...@btinternet.com wrote: On Mon, 15 Dec 2014 17:55:20 -0500, you wrote: Hi Simple answer - there is no simple answer. You will get significantly better results by intelligently processing the data than by a giant “average everything in

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Bill Hawkins
This may be one of those cases where the human brain's ability to see patterns would help to see the distribution and eliminate outliers. Plot a manageable set of X and Y points, and another set of X and Z points. To make the three dimensions plot as one in a statistical distribution (bell)

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Bob Camp
Hi On Dec 15, 2014, at 7:19 PM, Bill Hawkins b...@iaxs.net wrote: This may be one of those cases where the human brain's ability to see patterns would help to see the distribution and eliminate outliers. Plot a manageable set of X and Y points, and another set of X and Z points. yup

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Bob Camp
Hi Actually there may be a Time Nuts relevant reason for wanting to know the true / correct / survey location. If your desire is to know UTC to ns or something like that, an indicated position error *probably* relates directly to a time error. Being able to correct the position error may

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Hal Murray
kb...@n1k.org said: The problem shows up when the GPS constellation is in a configuration that accentuates the error. That’s often a 12 / 24 / 48 hour sort of thing. It would be interesting to compare the results from daytime vs nighttime, or today vs yesterday. -- These are my opinions.

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Bob Camp
Hi On Dec 15, 2014, at 8:07 PM, Hal Murray hmur...@megapathdsl.net wrote: kb...@n1k.org said: The problem shows up when the GPS constellation is in a configuration that accentuates the error. That’s often a 12 / 24 / 48 hour sort of thing. It would be interesting to compare the

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Paul
On Mon, Dec 15, 2014 at 6:39 PM, Angus not.ag...@btinternet.com wrote: But is it the closest to the 'true' position that you really want, or the best estimate of where the particular GPS you are testing thinks it is? I don't understand what you're saying here. Can you phrase it differently?

Re: [time-nuts] Did a member of time-nuts buy this?

2014-12-15 Thread Bob Camp
Hi Here’s another way to sort this all out: For ADEV, you probably want to get down to ~ 1x10^-13 at 1 second. If the system improves by 1/tau, it will be adequate for anything else you want to do. It’s a system that would need to resolve 100 fs, so most of the “counter” devices that die out

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Bob Camp
Hi On Dec 15, 2014, at 8:29 PM, Paul tic-...@bodosom.net wrote: On Mon, Dec 15, 2014 at 6:39 PM, Angus not.ag...@btinternet.com wrote: But is it the closest to the 'true' position that you really want, or the best estimate of where the particular GPS you are testing thinks it is? I

[time-nuts] Choke Rings and Points North

2014-12-15 Thread Dave M
With all the discussion about surveys position accuracy, I have a question about my choke ring antenna. There is an arrow marked N on the underside of the rings. How accurately does the alignment need to be to North? True north or magnetic north (my thinking says True North)? Does the

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Jim Lux
On 12/15/14, 5:35 PM, Bob Camp wrote: Hi On Dec 15, 2014, at 8:29 PM, Paul tic-...@bodosom.net wrote: On Mon, Dec 15, 2014 at 6:39 PM, Angus not.ag...@btinternet.com wrote: But is it the closest to the 'true' position that you really want, or the best estimate of where the particular GPS

Re: [time-nuts] Choke Rings and Points North

2014-12-15 Thread Bob Camp
Hi If: 1) You are doing a survey of a number of points in an area 2) You want to hit the “1/5 mm accuracy” that your system is rated to :) 3) You really do care Then: You point the arrow north to the best of your ability to make all the antenna errors show up in the same direction. It

Re: [time-nuts] Choke Rings and Points North

2014-12-15 Thread Jim Lux
On 12/15/14, 5:46 PM, Dave M wrote: With all the discussion about surveys position accuracy, I have a question about my choke ring antenna. There is an arrow marked N on the underside of the rings. How accurately does the alignment need to be to North? True north or magnetic north (my

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Paul
On Mon, Dec 15, 2014 at 8:35 PM, Bob Camp kb...@n1k.org wrote: So the question - If they are not going to be equal, which one do you pick? The better one. If the math is sound the presumably the better position results in better time. If there are correlated defects then I suppose the GPS

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Paul
On Mon, Dec 15, 2014 at 9:01 PM, Jim Lux jim...@earthlink.net wrote: if you've got observables and they're in RINEX format, you can do offline processing through JPL's GIPSY thing.. According to the upload form APPS still requires dual frequency. The underlying Gipsy system may not have that

Re: [time-nuts] GPS position averaging

2014-12-15 Thread Jim Lux
On 12/15/14, 6:46 PM, Paul wrote: On Mon, Dec 15, 2014 at 9:01 PM, Jim Lux jim...@earthlink.net wrote: if you've got observables and they're in RINEX format, you can do offline processing through JPL's GIPSY thing.. According to the upload form APPS still requires dual frequency. The

Re: [time-nuts] Choke Rings and Points North

2014-12-15 Thread Tom Van Baak
With all the discussion about surveys position accuracy, I have a question about my choke ring antenna. There is an arrow marked N on the underside of the rings. How accurately does the alignment need to be to North? True north or magnetic north (my thinking says True North)? Does the

Re: [time-nuts] Choke Rings and Points North

2014-12-15 Thread Dave M
Jim Lux wrote: On 12/15/14, 5:46 PM, Dave M wrote: With all the discussion about surveys position accuracy, I have a question about my choke ring antenna. There is an arrow marked N on the underside of the rings. How accurately does the alignment need to be to North? True north or magnetic

[time-nuts] Lady Heather and comm port setup...

2014-12-15 Thread Chuck Harris
Hi, I think the answer is probably no, but is there a sanctioned way of coercing the fine Lady into unusual comm port settings? For instance, can I get her to do: 9600, 8, Odd, 1 without resorting to the whip? Thanks! -Chuck Harris ___ time-nuts

[time-nuts] Lady Heather and comm port setup...

2014-12-15 Thread Chuck Harris
Hi, I think the answer is probably no, but is there a sanctioned way of coercing the fine Lady into unusual comm port settings? For instance, can I get her to do: 9600, 8, Odd, 1 without resorting to handcuffs, and the whip? Thanks! -Chuck Harris