On 2014-03-21 20:50, Chris Albertson wrote:
What's the best way to make an ADEV plot, other then using time lab?
Timelab appears to be an MS Windows .exe file.I could write a
script based on the definition of adev but I bet someone has already
done this.
Look for recent and some earlier
jleik...@leikhim.com said:
In retrospect it is kind of crazy that fleet owners will put tracking
devices on $100K semi trucks and cranes yet $100 million aircraft have to
rely upon 60 year old technology (Transponders) and ACARS to keep track of
them. I don't question the utility of TCAS and
From: Hal Murray
There is a newer system getting phased in: ADS-B
http://en.wikipedia.org/wiki/Automatic_dependent_surveillance-broadcast
The plane broadcasts it's position and velocity every second.
The SDR folks are having fun with it. With one of the USB TV receiver
gizmos
and a
In message 532d1009.6040...@leikhim.com, Joe Leikhim writes:
In retrospect it is kind of crazy that fleet owners will put
tracking devices on $100K semi trucks and cranes yet $100 million
aircraft have to rely upon 60 year old technology (Transponders)
and ACARS to keep track of them.
Pilots
On 3/21/14 8:52 PM, nuts wrote:
On Thu, 20 Mar 2014 14:42:42 -0400
Joe Leikhim jleik...@leikhim.com wrote:
I just red somewhere that the last ping was the only one recorded
by Inmarsat system, Pings up to that point were presumed to occur due
to known reporting intervals. So there is no track.
On Fri, Mar 21, 2014 at 11:22 PM, Joe Leikhim jleik...@leikhim.com wrote:
In retrospect it is kind of crazy that fleet owners will put tracking
devices on $100K semi trucks and cranes yet $100 million aircraft have to
rely upon 60 year old technology (Transponders) and ACARS to keep track of
On 22/03/14 09:01, Poul-Henning Kamp wrote:
In message 532d1009.6040...@leikhim.com, Joe Leikhim writes:
In retrospect it is kind of crazy that fleet owners will put
tracking devices on $100K semi trucks and cranes yet $100 million
aircraft have to rely upon 60 year old technology
I'm not so sure it is worth much as parts, except possibly on the black
market. I believe the aircraft industry is big on tracking every part,
cradle to grave. After all an under spec bolt can cause a very expensive
crash.
YMMV,
-John
==
In retrospect it is kind of crazy
On 22/03/14 13:17, Tom Van Baak wrote:
What's the best way to make an ADEV plot, other then using time lab?
Timelab appears to be an MS Windows .exe file.I could write a
script based on the definition of adev but I bet someone has already
done this.
Chris,
John's TimeLab gives you much
Claude,
On 22/03/14 12:48, Claude Fender wrote:
Hi,
I have two generators 3324A and 33120A and one counter 5334B. All the
instruments are locked to a GPSDO.
I've measures a 1 kHz output of the generators with the counter set with a
gate time of 1 second, and repeated the measure 3600
On 3/19/14 9:50 AM, Chris Albertson wrote:
So they want to in-invent NTP?
I think NTP already services way more than 6.5 billion per day. The
problem with NTP is while it is nearly optimal and provides the best
time accuracy for a given hardware/network setup it is not technically
traceable
Yes I could run most any MS Windows software on my iMac. But running
it is not the point. Closed source software like this is just a
magic black box and you can't see how it works.
The point is like this: Why build a GPSDO when you can simply buy a
Thunderbolt, apply power and go?The same
I can see a use for an inexpensive GPSDO with a built-in
gigabit ethernet or USB3 port powering an NTP server.
On 03/19/2014 10:21 AM, Jim Lux wrote:
On 3/19/14 9:50 AM, Chris Albertson wrote:
So they want to in-invent NTP?
I think NTP already services way more than 6.5 billion per day. The
On 22/03/14 19:56, John Ackermann wrote:
We discontinued selling kits for the TAPR TADD-1 distribution amplifier
a couple of years ago when the MAX477 amplifier at the heard of the
design became unobtanium. There were reports that the Analog Devices
AD8055 was a drop-in replacement, but I
Actually traceability of parts for maintenance has nothing to do with unions
and national security. It has everything to do with failure analysis.
If a part fails it's entire path from manufacturer to maintanance and repair
shops can be traced so if a part starts experiencing failures at Sn
On Sat, Mar 22, 2014 at 12:24 PM, Chuck Forsberg WA7KGX c...@omen.com wrote:
I can see a use for an inexpensive GPSDO with a built-in
gigabit ethernet or USB3 port powering an NTP server.
Neither of those is a good way to transfer time to an NTP server.
Both Ethernet and USB are packetized.
On Sat, Mar 22, 2014 at 2:24 PM, Chuck Forsberg WA7KGX c...@omen.com wrote:
I can see a use for an inexpensive GPSDO with a built-in
gigabit ethernet or USB3 port powering an NTP server.
Why not a BeagleBoneBlack with a GPS module that has 1pps out connected to
an I/O pin. For that matter,
Can you imagine how much an aircraft like that is worth in spare parts
alone?
It is worth more as scrap metal.
There is no market for untraced spare parts for large passenger jets.
I was just going to say the same thing. Selling parts from a stolen
777 is like being an art thieve who just
The PRUs (Programmable Realtime Unit) aren't a feature of ARM in general
(they are not present
on the Raspberry Pi for instance). The BeagleBone has 2 PRUs as you
describe. It uses the TI Siatra
ARM variant.
ARM just describes the core architecture. Manufacturers tack on all
sorts of
On Sat, Mar 22, 2014 at 4:16 PM, Brian Lloyd br...@lloyd.com wrote:
I bet you can come up with an NTP server and a GPSDO for not more than
$200.
I believe the Laureline largely meets the spec. It all open -- hardware
and software.
It's not gigE but it was suggested you could swap in a 1588
Not complaining. Just looking for open source tools to do the
analysis before I write them myself. I figured someone must have done
this. Found it in ../tools as you said. Thanks.
Plotting is the easy part, any number of tools to do that, analysis is harder.
I'm looking at your simulation
On Fri, 21 Mar 2014 14:55:34 -0700, Tom Van Baak wrote:
Have a look and let me know what you think. The tool is gpsim1.c
(Windows: gpsim1.exe) under:
http://www.leapsecond.com/tools/
Nice tool Tom
I just compiled it under linux.
gcc gpsim1.c -lm -o gpsim1
I had to add min/max
#define
Hi Tom,
On 22/03/14 21:00, Tom Van Baak wrote:
Hi Chris,
I'm pretty sure John distributes complete source code to TimeLab as part of the
installation.
My source code is at www.leapsecond.com/tools
There are also many open source plotting tools available.
Not sure what you're complaining
Thanks, Yes of course ARM refers only to ARM
Would you know which other systems include the PRUs? Is it only in
the TI products? It seems like an ideal solution to the problem of
non-deterministic latency.
This may not even be required. There is no point to extreme levels of
accuracy
On 22/03/14 21:19, Chris Albertson wrote:
Can you imagine how much an aircraft like that is worth in spare parts alone?
It is worth more as scrap metal.
There is no market for untraced spare parts for large passenger jets.
I was just going to say the same thing. Selling parts from a stolen
On 22/03/14 22:13, Magnus Danielson wrote:
Hi Tom,
On 22/03/14 21:00, Tom Van Baak wrote:
Hi Chris,
I'm pretty sure John distributes complete source code to TimeLab as
part of the installation.
My source code is at www.leapsecond.com/tools
There are also many open source plotting tools
Hi Brian:
MH370 had both ACARS and ADS-B, they have not been of any help.
ACARS can send it's data using (in order) VHF, Inmarsat, HF.
The problem is that ACARS quit sending information.
MH370 did not have a contract wtih Inmarsat.
ADS-B is built using W.W.II IFF technology (1090/1030 MHz, i.e.
On Sat, Mar 22, 2014 at 3:53 PM, Chris Albertson
albertson.ch...@gmail.comwrote:
Thanks, Yes of course ARM refers only to ARM
Would you know which other systems include the PRUs? Is it only in
the TI products? It seems like an ideal solution to the problem of
non-deterministic latency.
albertson.ch...@gmail.com said:
Would you know which other systems include the PRUs? Is it only in the TI
products? It seems like an ideal solution to the problem of
non-deterministic latency.
There is a much simpler solution - avoid the latency by using a counter/timer
to capture the
In message 532e01ee.3040...@pacific.net, Brooke Clarke writes:
There are two scenarios regarding MH370: [...]
Three: 3) Somebody stole the plane for some reason.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer |
The main problem for NIST or USNO's servers is not the actual time
transfer into the machine -- that is a solved problem, but rather
getting enough packets spit out precisely enough, with the required
signature to make it traceable.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
Many thanks Tom for an excellent tool and also the data you have provided. You
don´t happen to have data for a non sawtooth corrected M12?
Another question: how do you insert the options for ticres and dacbits? With
“gpsim1 avg1=10 gps-mtk3339.txt ocxo.dat gpsdo.txt” I managed to get
On Sat, Mar 22, 2014 at 2:25 PM, Brian Lloyd br...@lloyd.com wrote:
NTP running in broadcast mode over a local Gig-E network shouldn't be too
bad. I suspect timing jitter is pretty low.
Gigabit Ethernet can be actually worse than 100BaseT because of the
way the hardware works. The packets
The PRU on the BeagleBone each include an enhanced capture module that
can be used as you describe.
It has a 32 bit timer that is latched into one of the capture
registers. The timers are independent of
the timer used by the Linux system so I'm not sure how you would tie
them into use with
In message 532e1620.9080...@tuffmail.us, Mike George writes:
The PRU on the BeagleBone each include an enhanced capture module that
can be used as you describe.
I belive there is also some magic in the ethernet controller, but
I have yet to study it carefully.
--
Poul-Henning Kamp |
At this time, the most likely story was written by a pilot and appeared
in Wired magazine.
Google MH370 smoke and look for the Wired reference.
Bill Hawkins
-Original Message-
From: Poul-Henning Kamp
Sent: Saturday, March 22, 2014 5:44 PM
In message 532e01ee.3040...@pacific.net, Brooke
PRU appears to be unique to TI.
I have only used Raspberry Pi, Beaglebone, and Cubieboard.
The Cubieboard (Allwinner CPU) has a lot of IO pins like the
Beaglebone but nothing like a PRU.
Mike George
On 3/22/2014 16:53, Chris Albertson wrote:
Thanks, Yes of course ARM refers only to ARM
On 23/03/14 02:06, Magnus Danielson wrote:
Hi
As follow-up on the previous message, where I varied the TIC resolution,
let's vary the TIC averaging for the TIC resolution of 100 ns, which we
know has some effect. The default TIC averaging is for 100 s, so I
varied it for 1, 10, 100 and 1000 s.
Hi Tom et.al. Isn't the simulator easily convertible to the real thing?
That is, data inputs should be convertible somehow to data streams from
physical devices?
Don
cfo
On Fri, 21 Mar 2014 14:55:34 -0700, Tom Van Baak wrote:
Have a look and let me know what you think. The tool is gpsim1.c
On Sat, Mar 22, 2014 at 6:55 PM, Chris Albertson
albertson.ch...@gmail.comwrote:
But as I wrote before if you are on a local network and are willing to
buy special PTP compatible hardware you can use PTP and avoid NTP.
PTP relies on external time stamps put on but the network hardware and
is
Hi Don,
Yes, easy! And that's exactly the idea -- to take real inputs (or borrowed
copies of real inputs), and a real software algorithm, and measure the virtual
output to see how well your algorithm and tunable parameters work. Tweak
parameters. Evolve the algorithm. Simmer until well done.
Tom,
In my experience one of the biggest GPSDO error sources in low-cost and even
some higher end OCXOs is oscillator hysteresis. Which can change with operating
temperature, operating time (crystal age) and even over crystal tilt.
Does your OCXO model allow for hysteresis simulation?
It is
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