[time-nuts] Venus838LPx-T opinions?

[Nick Sayer via time-nuts]

Anybody played with one of these? http://www.skytraq.com.tw/products/products-Timing%20Module.html

It looks promising for GPSDO designers. It has a survey mode (looks to be automatic) and one of the NMEA messages reports quantization error.

The downsides I’ve identified so far are that it’s an LGA69, so that’ll be… exciting… And I don’t have any pricing, availability or minimum order information at the moment.
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[Mark Sims]

Navspark will sell you one in on a board for around $80. They claim 6 ns timing accuracy. Also 0.01 ppb on the 10 MHz output. I sent Navspark a couple of questions about their USB interface and they never responded...

http://navspark.mybigcommerce.com/ns-t-precision-timing-gps-receiver/

---------------------------

Post by Nick Sayer via time-nuts
Anybody played with one of these?

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[Nick Sayer via time-nuts]

Looks like the bare modules are available for $25 (FOB Taiwan) each MQ:4. Eminently reasonable. I am probably going to get 4 to start with and make an LGA breakout board for myself and do some experimenting with them.

The tough part for me is going to be upgrading the controller to the ATMega328PB to get enough flash space to add the sawtooth compensation handling stuff. But even if I completely ignore the NMEA output of the module, it'll be worth it to get timing firmware with survey capabilities. I'm quite excited.

Sent from my iPhone

Post by Nick Sayer via time-nuts
Anybody played with one of these? http://www.skytraq.com.tw/products/products-Timing%20Module.html
It looks promising for GPSDO designers. It has a survey mode (looks to be automatic) and one of the NMEA messages reports quantization error.
The downsides I’ve identified so far are that it’s an LGA69, so that’ll be… exciting… And I don’t have any pricing, availability or minimum order information at the moment.
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...

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[Clay Autery]

Looks like a module I might want to start with... No way I'd want to
start with the chip...

______________________
Clay Autery, KY5G
MONTAC Enterprises
[phone]

Post by Nick Sayer via time-nuts
Looks like the bare modules are available for $25 (FOB Taiwan) each MQ:4. Eminently reasonable. I am probably going to get 4 to start with and make an LGA breakout board for myself and do some experimenting with them.
The tough part for me is going to be upgrading the controller to the ATMega328PB to get enough flash space to add the sawtooth compensation handling stuff. But even if I completely ignore the NMEA output of the module, it'll be worth it to get timing firmware with survey capabilities. I'm quite excited.
Sent from my iPhone

Post by Nick Sayer via time-nuts
Anybody played with one of these? http://www.skytraq.com.tw/products/products-Timing%20Module.html
It looks promising for GPSDO designers. It has a survey mode (looks to be automatic) and one of the NMEA messages reports quantization error.
The downsides I’ve identified so far are that it’s an LGA69, so that’ll be… exciting… And I don’t have any pricing, availability or minimum order information at the moment.

...

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[Mark Sims]

I'd get the $80 assembled unit from Navspark first and see if it works for you. If not, you won't have wasted your time and money on doing a PC board.

Lady Heather can now talk to Venus receivers in binary mode (also handles generic NMEA receivers). I don't have a Venus timing receiver so I have not tested operation of the timing receiver related messages. One VERY vexing issue with Venus binary mode is there is NO binary message that provides "sky view" info about satellite positions and signal levels. You can only get that in NMEA mode.
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[Clay Autery]

Definitely the assembled "breakout board+". Maybe I'll wait til Lady
Heather has a more complete communication set with this part...

______________________
Clay Autery, KY5G
MONTAC Enterprises
[phone]

Post by Mark Sims
I'd get the $80 assembled unit from Navspark first and see if it works for you. If not, you won't have wasted your time and money on doing a PC board.
Lady Heather can now talk to Venus receivers in binary mode (also handles generic NMEA receivers). I don't have a Venus timing receiver so I have not tested operation of the timing receiver related messages. One VERY vexing issue with Venus binary mode is there is NO binary message that provides "sky view" info about satellite positions and signal levels. You can only get that in NMEA mode.
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[Mark Sims]

I have implemented support for all of the relevant Venus binary messages. It's just that I don't have a Venus timing receiver to test the timing receiver specific messages (which are only three messages that control the self-survey / position hold modes). Oh, and besides the lack of a binary message with satellite position/signal levels, there is none that reports the sawtooth error.

Lady Heather's NMEA support is limited to standard NMEA messages that all receivers support (position, date/time, satellite info). The only "proprietary" NMEA commands that I send are those that can switch a receiver into binary mode. Receiver binary modes generally allow full control over the receiver.

-------------------------

Maybe I'll wait til Lady Heather has a more complete communication set with this part...
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[Charles Steinmetz]

Post by Mark Sims
Oh, and besides the lack of a binary message with satellite position/signal levels, there is none that reports the sawtooth error.

How in the world can they call it a "timing receiver" if it doesn't even
support sawtooth correction?? Good grief.

Also, I see they claim 6nS accuracy. That is pretty much exactly 1/2
cycle of the main clock frequency, so +/- 6nS should be the expected
theoretical best possible error envelope WRT the quantization error,
*assuming the receiver's timing solution is always perfect.* Are we
supposed to believe they achieve that accuracy in practice, despite all
of the well-known sources of error in GPS timing solutions??

Best regards,

Charles


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[Nick Sayer via time-nuts]

The NMEA STI,00 message gives a sawtooth correction. I believe what Mark was saying was that there was no *binary* message that said so… maybe? I dunno. But the datasheet clearly talks about PPS quantization error compensation:


STI,00 – 1 PPS timing report

An output message, id 0x0, contains information of 1 PPS timing mode, 1 PPS survey length and 1PPS quantization error.

Structure:
$PSTI,00,x,xx,xx *hh<CR><LF>


Example: $PSTI,00,1,1985,-12.4*1E<CR><LF>

Here there’s a table that I’ll try to interpolate because pasting it failed…

the 1 is the PPS timing mode. 0 = PVT, 1 = Survey mode, 2 = Static mode
1985 is the survey length
-12.4 is the PPS quantization error
1E is, of course, the checksum.

Post by Mark Sims
Oh, and besides the lack of a binary message with satellite position/signal levels, there is none that reports the sawtooth error.

How in the world can they call it a "timing receiver" if it doesn't even support sawtooth correction?? Good grief.
Also, I see they claim 6nS accuracy. That is pretty much exactly 1/2 cycle of the main clock frequency, so +/- 6nS should be the expected theoretical best possible error envelope WRT the quantization error, *assuming the receiver's timing solution is always perfect.* Are we supposed to believe they achieve that accuracy in practice, despite all of the well-known sources of error in GPS timing solutions??
Best regards,
Charles
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[Mark Sims]

Yes, no Venus binary messages for sky view or sawtooth correction. Those are only available in NMEA. But to make effective use of a timing receiver you should be running it in binary where you can properly monitor and control it. Whoever did the Venus binary commands did not think things through... and I don't think that they knew much about timing receivers and their application.
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[Gary E. Miller]

Yo Mark!

On Sat, 23 Jul 2016 17:13:27 +0000

Post by Mark Sims
Yes, no Venus binary messages for sky view or sawtooth correction.
Those are only available in NMEA. But to make effective use of a
timing receiver you should be running it in binary where you can
properly monitor and control it.

The Venus is weird that way. When it is doing Binary, it mixes in
NMEA. So you can see both in the serial stream.

I have run the Veuus 8 in Binary and NMEA modes. The basics
are in NMEA, the configuration and fancy stuff in their binary
sentences. Mixing and matching is just not a problem.

In timing mode you care about the PPS and that is independent
of the serial stream anyway.

I have two Venus 8 EVBs (NS-HP) right in front of me. They are in
base/rover mode and I'm seeing CEP(50) of centi-meter relative accuracy.
I do not have a timing version, but I can believe at least 50% of the
time it would be very stable. Like all GPS it does go on drunken
excursions now and then.

The accuracy is so good it exceeds the math accuracy of my scatter
plot program. Working on recoding that now.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
***@rellim.com Tel:[phone]

[Bob Stewart]

In timing mode, you care very much about the quantization error messages.
Bob
 -----------------------------------------------------------------
AE6RV.com

GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info

From: Gary E. Miller <***@rellim.com>
To: Mark Sims <***@hotmail.com>
Cc: "time-***@febo.com" <time-***@febo.com>
Sent: Saturday, July 23, 2016 7:52 PM
Subject: Re: [time-nuts] Venus838LPx-T opinions?

Yo Mark!

On Sat, 23 Jul 2016 17:13:27 +0000

Post by Mark Sims
Yes, no Venus binary messages for sky view or sawtooth correction.
Those are only available in NMEA.  But to make effective use of a
timing receiver you should be running it in binary where you can
properly monitor and control it.

The Venus is weird that way.  When it is doing Binary, it mixes in
NMEA.  So you can see both in the serial stream.

I have run the Veuus 8 in Binary and NMEA modes.  The basics
are in NMEA, the configuration and fancy stuff in their binary
sentences.  Mixing and matching is just not a problem.

In timing mode you care about the PPS and that is independent
of the serial stream anyway.

I have two Venus 8 EVBs (NS-HP) right in front of me.  They are in
base/rover mode and I'm seeing CEP(50) of centi-meter relative accuracy.
I do not have a timing version, but I can believe at least 50% of the
time it would be very stable.  Like all GPS it does go on drunken
excursions now and then.

The accuracy is so good it exceeds the math accuracy of my scatter
plot program.  Working on recoding that now.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
    ***@rellim.com  Tel:[phone]
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[Mark Sims]

Lady Heather now works with Venus receivers in mixed binary / NMEA mode. So now it can display the sky view data (via NMEA sentences) while running in Venus binary mode. I also added support for parsing the $PSTI NMEA sentence that contains the sawtooth correction info. Why somebody thought it was a good idea to not include that info in the binary messages boggles the mind... I hate having my mind boggled.

I guess I may have to buy one of the Navspark timing receivers...
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[Gary E. Miller]

Yo Mark!

On Sun, 24 Jul 2016 05:23:54 +0000

Post by Mark Sims
Why somebody thought it was a good idea to not include that info in
the binary messages boggles the mind... I hate having my mind
boggled.

For some reasaon they never seem to ask us before designing their
protocols...

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
***@rellim.com Tel:[phone]

[Clay Autery]

AWESOME!!! :)

Added to project list!!!

Mark, what's your official link to Lady Heather.... and how do we donate
to the cause?

73,

______________________
Clay Autery, KY5G
MONTAC Enterprises
[phone]

Post by Mark Sims
Lady Heather now works with Venus receivers in mixed binary / NMEA mode. So now it can display the sky view data (via NMEA sentences) while running in Venus binary mode. I also added support for parsing the $PSTI NMEA sentence that contains the sawtooth correction info. Why somebody thought it was a good idea to not include that info in the binary messages boggles the mind... I hate having my mind boggled.
I guess I may have to buy one of the Navspark timing receivers...

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[Mark Sims]

I am the creator author of Lady Heather. The code in Lady Heather started out from a program that I wrote to control Magellan GPS receivers (like the OEM-5000) back in days of the first Gulf War... it ran under DOS as a text mode only program.

When TAPR did their group buy for Trimble Thunderbolts I bought one and modified the code to work with it. Again, basically a DOS program that could run under Windows and do some plotting. The idea was to keep it simple and had a lot of kludges to minimize memory usages so it could run on low-end discarded machines.

John Miles added support for running properly under Windows using his WIN_VFX library. Then the fun began and things began to get out of control. Lots of new features, silly features, useful features, not so useful features were added. There is still code/compile options in there for a DOS compatible compile, but too much has been added for that to ever work again...

A few months back, I added support for working under Linux using X11 as the graphics / keyboard interface. That code is what it in the Rev 4.0 beta that is on John's web site.

Lately I have been adding support for working with receivers other than those in the Trimble Thunderbolt family. It is now working with Trimble, Motorola, Jupiter, Sirf, Venus, Ublox, NMEA, SCPI (Z38xx), UCCM, and a few others. It also works with GPSD (a sort of universal GPS receiver interface for Linux). It can also work as a system clock display without a GPS receiver connected.

I hope to have the newest code finalized and released shortly... I'm waiting on a couple of new receivers to come in.

Lady Heather is free, open-source software now released under the very permissive MIT license...
----------

Mark, what's your official link to Lady Heather.... and how do we donate to the cause?

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[Clay Autery]

LOL!

Thank so much for the history of how you got trapped... errr started in
the Lady Heather software project. :)

Questions still remain:

1) What is the link to the "official" Lady Heather site?
2) How/where can we shoot a donation to say "Thanks!"?

73,

______________________
Clay Autery, KY5G
MONTAC Enterprises
[phone]

Post by Mark Sims
I am the creator author of Lady Heather. The code in Lady Heather started out from a program that I wrote to control Magellan GPS receivers (like the OEM-5000) back in days of the first Gulf War... it ran under DOS as a text mode only program.
When TAPR did their group buy for Trimble Thunderbolts I bought one and modified tcode to work with it. Again, basically a DOS program that could run under Windows and do some plotting. The idea was to keep it simple and had a lot of kludges to minimize memory usages so it could run on low-end discarded machines.
John Miles added support for running properly under Windows using his WIN_VFX library. Then the fun began and things began to get out of control. Lots of new features, silly features, useful features, not so useful features were added. There is still code/compile options in there for a DOS compatible compile, but too much has been added for that to ever work again...
A few months back, I added support for working under Linux using X11 as the graphics / keyboard interface. That code is what it in the Rev 4.0 beta that is on John's web site.
Lately I have been adding support for working with receivers other than those in the Trimble Thunderbolt family. It is now working with Trimble, Motorola, Jupiter, Sirf, Venus, Ublox, NMEA, SCPI (Z38xx), UCCM, and a few others. It also works with GPSD (a sort of universal GPS receiver interface for Linux). It can also work as a system clock display without a GPS receiver connected.
I hope to have the newest code finalized and released shortly... I'm waiting on a couple of new receivers to come in.
Lady Heather is free, open-source software now released under the very permissive MIT license...
----------

Mark, what's your official link to Lady Heather.... and how do we donate to the

...

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[Dave Mallery]

I have been running Heather on Ubuntu MATE 16-04 since Mark released it.
Wonderful.

Currently running or a R Pi 3B with lots of machine to spare!

Cheers!

Dave Mallery

Post by Mark Sims
I am the creator author of Lady Heather. The code in Lady Heather
started out from a program that I wrote to control Magellan GPS receivers
(like the OEM-5000) back in days of the first Gulf War... it ran under DOS
as a text mode only program.
When TAPR did their group buy for Trimble Thunderbolts I bought one and
modified the code to work with it. Again, basically a DOS program that
could run under Windows and do some plotting. The idea was to keep it
simple and had a lot of kludges to minimize memory usages so it could run
on low-end discarded machines.
John Miles added support for running properly under Windows using his
WIN_VFX library. Then the fun began and things began to get out of
control. Lots of new features, silly features, useful features, not so
useful features were added. There is still code/compile options in there
for a DOS compatible compile, but too much has been added for that to ever
work again...
A few months back, I added support for working under Linux using X11 as
the graphics / keyboard interface. That code is what it in the Rev 4.0
beta that is on John's web site.
Lately I have been adding support for working with receivers other than
those in the Trimble Thunderbolt family. It is now working with Trimble,
Motorola, Jupiter, Sirf, Venus, Ublox, NMEA, SCPI (Z38xx), UCCM, and a few
others. It also works with GPSD (a sort of universal GPS receiver
interface for Linux). It can also work as a system clock display without a
GPS receiver connected.
I hope to have the newest code finalized and released shortly... I'm
waiting on a couple of new receivers to come in.
Lady Heather is free, open-source software now released under the very
permissive MIT license...
----------

Post by Clay Autery
Mark, what's your official link to Lady Heather.... and how do we donate

to the cause?
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...

[Mark Sims]

The closest thing to an official Lady Heather site if John Mile's ke5fx.com I also want to put it it up on Github when the code settles down some.

The good Lady Heather doesn't accept donations of the monetary kind. Receivers not currently hoarded in her dungeon are appreciated. Particularly interested in RFTG-M, Z3805. Z3815, Z3816, and HP53xxx at the moment (or somebody to test them). Code is in there for working with these, but it has never been tested on a real device (and SCPI tends to be rather picky about just how you have to talk to it).

-------------------
Questions still remain:

1) What is the link to the "official" Lady Heather site?
2) How/where can we shoot a donation to say "Thanks!"?



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[Bill Riches]

Hi Mark,

If you are ever interested in playing with the Lucent boxes (Z3811, Z3812) I would be glad to send you a working system to play with. Sure would like to use LH with it.

73,

Bill, WA2DVU
Cape May, NJ

-----Original Message-----
From: time-nuts [mailto:time-nuts-***@febo.com] On Behalf Of Mark Sims
Sent: Sunday, July 24, 2016 7:34 PM
To: time-***@febo.com
Subject: [time-nuts] Venus838LPx-T opinions?

The closest thing to an official Lady Heather site if John Mile's ke5fx.com I also want to put it it up on Github when the code settles down some.

The good Lady Heather doesn't accept donations of the monetary kind. Receivers not currently hoarded in her dungeon are appreciated. Particularly interested in RFTG-M, Z3805. Z3815, Z3816, and HP53xxx at the moment (or somebody to test them). Code is in there for working with these, but it has never been tested on a real device (and SCPI tends to be rather picky about just how you have to talk to it).

-------------------
Questions still remain:

1) What is the link to the "official" Lady Heather site?
2) How/where can we shoot a donation to say "Thanks!"?



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[Mark Sims]

I have a Z3812A that I added back in the GPS receiver and modified it (moving 6 zero ohm resistors) to work as a standalone GPS. Basically it's now a stand-alone Z3811. I have Lady Heather working with it now. The hack of using the RS-422 output to directly drive a RS-232 serial port does not work very well with most older RS-232 receiver chips. I have to control it with a USB-Serial cable.

------------------
If you are ever interested in playing with the Lucent boxes (Z3811, Z3812) I would be glad to send you a working system to play with. Sure would like to use LH with it.
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