Empathy List Archives

SC

Stewart Cobb

Sun, Aug 9, 2020 9:53 PM

Taka Kamiya and Forrest Christian both asked recently about the alternative
satellite PNT system using the Iridium satellites. That system was
developed by my company, Satelles. It has been commercially available for
more than a year now.

The biggest advantage is that our signal is at least 30 dB stronger than
GNSS signals (the exact numbers depend on whether you're talking to
engineering or marketing :). You can easily get a usable signal in deep
jungle, or a data center in the middle of a building's basement, or even
inside a locked shipping container. The stronger signal is correspondingly
more difficult to jam or spoof than GNSS, and our signal has anti-spoofing
features as well.

The biggest disadvantage is that it is not quite as accurate as GPS,
because there are fewer satellites in view at any given time.

I don't want to quote exact timing numbers here, because they depend a lot
on system integration details, but you can easily steer an OCXO within a
few hundred nanoseconds of USNO time. With a rubidium, you can do
considerably better.

If you want to know more, our website is www.satellesinc.com.

(If this message has been too commercial, I apologize in advance. The
boundary between information and salesmanship is not always sharp.)

Cheers!
--Stu

Taka Kamiya and Forrest Christian both asked recently about the alternative satellite PNT system using the Iridium satellites. That system was developed by my company, Satelles. It has been commercially available for more than a year now. The biggest advantage is that our signal is at least 30 dB stronger than GNSS signals (the exact numbers depend on whether you're talking to engineering or marketing :). You can easily get a usable signal in deep jungle, or a data center in the middle of a building's basement, or even inside a locked shipping container. The stronger signal is correspondingly more difficult to jam or spoof than GNSS, and our signal has anti-spoofing features as well. The biggest disadvantage is that it is not quite as accurate as GPS, because there are fewer satellites in view at any given time. I don't want to quote exact timing numbers here, because they depend a lot on system integration details, but you can easily steer an OCXO within a few hundred nanoseconds of USNO time. With a rubidium, you can do considerably better. If you want to know more, our website is www.satellesinc.com. (If this message has been too commercial, I apologize in advance. The boundary between information and salesmanship is not always sharp.) Cheers! --Stu

TV

Tom Van Baak

Sun, Aug 9, 2020 11:03 PM

Hi Stu,

There's no problem with a semi-commercial posting here. You've been a
member for a decade and frequent contributor plus the subject matter is
exactly on-topic. So thanks for posting.

I spent a while on your web site and didn't uncover a trove of white
papers. If you could post some URL's that would be appreciated. You
don't have to worry about being less accurate than GPS. I mean, there
are often far more important factors than nanosecond precision. You
didn't mention pricing; it's hard to imagine it's as free as GPS so that
seems like another disadvantage to me.

Your comment about fewer satellites is spot on. That will be taken care
of if you give SpaceX / Starlink a call and join that bandwagon. There
are already 597 Starlink [1] satellites up there vs. 82 Iridium [2]
satellites, yes?

If you have entry-level / hobbyist grade evaluation kits I'm sure a
number of us would be very interested to try it out.

Thanks,
/tvb

[1] https://en.wikipedia.org/wiki/Starlink

[2] https://en.wikipedia.org/wiki/Iridium_satellite_constellation

On 8/9/2020 2:53 PM, Stewart Cobb wrote:

Taka Kamiya and Forrest Christian both asked recently about the alternative
satellite PNT system using the Iridium satellites. That system was
developed by my company, Satelles. It has been commercially available for
more than a year now.

The biggest advantage is that our signal is at least 30 dB stronger than
GNSS signals (the exact numbers depend on whether you're talking to
engineering or marketing :). You can easily get a usable signal in deep
jungle, or a data center in the middle of a building's basement, or even
inside a locked shipping container. The stronger signal is correspondingly
more difficult to jam or spoof than GNSS, and our signal has anti-spoofing
features as well.

The biggest disadvantage is that it is not quite as accurate as GPS,
because there are fewer satellites in view at any given time.

I don't want to quote exact timing numbers here, because they depend a lot
on system integration details, but you can easily steer an OCXO within a
few hundred nanoseconds of USNO time. With a rubidium, you can do
considerably better.

If you want to know more, our website is www.satellesinc.com.

(If this message has been too commercial, I apologize in advance. The
boundary between information and salesmanship is not always sharp.)

Cheers!
--Stu

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Hi Stu, There's no problem with a semi-commercial posting here. You've been a member for a decade and frequent contributor plus the subject matter is exactly on-topic. So thanks for posting. I spent a while on your web site and didn't uncover a trove of white papers. If you could post some URL's that would be appreciated. You don't have to worry about being less accurate than GPS. I mean, there are often far more important factors than nanosecond precision. You didn't mention pricing; it's hard to imagine it's as free as GPS so that seems like another disadvantage to me. Your comment about fewer satellites is spot on. That will be taken care of if you give SpaceX / Starlink a call and join that bandwagon. There are already 597 Starlink [1] satellites up there vs. 82 Iridium [2] satellites, yes? If you have entry-level / hobbyist grade evaluation kits I'm sure a number of us would be very interested to try it out. Thanks, /tvb [1] https://en.wikipedia.org/wiki/Starlink [2] https://en.wikipedia.org/wiki/Iridium_satellite_constellation On 8/9/2020 2:53 PM, Stewart Cobb wrote: > Taka Kamiya and Forrest Christian both asked recently about the alternative > satellite PNT system using the Iridium satellites. That system was > developed by my company, Satelles. It has been commercially available for > more than a year now. > > The biggest advantage is that our signal is at least 30 dB stronger than > GNSS signals (the exact numbers depend on whether you're talking to > engineering or marketing :). You can easily get a usable signal in deep > jungle, or a data center in the middle of a building's basement, or even > inside a locked shipping container. The stronger signal is correspondingly > more difficult to jam or spoof than GNSS, and our signal has anti-spoofing > features as well. > > The biggest disadvantage is that it is not quite as accurate as GPS, > because there are fewer satellites in view at any given time. > > I don't want to quote exact timing numbers here, because they depend a lot > on system integration details, but you can easily steer an OCXO within a > few hundred nanoseconds of USNO time. With a rubidium, you can do > considerably better. > > If you want to know more, our website is www.satellesinc.com. > > (If this message has been too commercial, I apologize in advance. The > boundary between information and salesmanship is not always sharp.) > > Cheers! > --Stu > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. >

BK

Bob kb8tq

Mon, Aug 10, 2020 12:52 AM

Hi

On Aug 9, 2020, at 7:03 PM, Tom Van Baak tvb@LeapSecond.com wrote:

Hi Stu,

There's no problem with a semi-commercial posting here. You've been a member for a decade and frequent contributor plus the subject matter is exactly on-topic. So thanks for posting.

I spent a while on your web site and didn't uncover a trove of white papers. If you could post some URL's that would be appreciated. You don't have to worry about being less accurate than GPS. I mean, there are often far more important factors than nanosecond precision.

To that point ( as accurate as GPS ) ….. GPS is simply a convent comparison system. Saying that
this or that is better or worse at this or that tau is not the same as saying it has more or less value.
It’s simply a system that is out there to be compared to.

Bob

You didn't mention pricing; it's hard to imagine it's as free as GPS so that seems like another disadvantage to me.

Your comment about fewer satellites is spot on. That will be taken care of if you give SpaceX / Starlink a call and join that bandwagon. There are already 597 Starlink [1] satellites up there vs. 82 Iridium [2] satellites, yes?

If you have entry-level / hobbyist grade evaluation kits I'm sure a number of us would be very interested to try it out.

Thanks,
/tvb

[1] https://en.wikipedia.org/wiki/Starlink

[2] https://en.wikipedia.org/wiki/Iridium_satellite_constellation

On 8/9/2020 2:53 PM, Stewart Cobb wrote:

Taka Kamiya and Forrest Christian both asked recently about the alternative
satellite PNT system using the Iridium satellites. That system was
developed by my company, Satelles. It has been commercially available for
more than a year now.

The biggest advantage is that our signal is at least 30 dB stronger than
GNSS signals (the exact numbers depend on whether you're talking to
engineering or marketing :). You can easily get a usable signal in deep
jungle, or a data center in the middle of a building's basement, or even
inside a locked shipping container. The stronger signal is correspondingly
more difficult to jam or spoof than GNSS, and our signal has anti-spoofing
features as well.

The biggest disadvantage is that it is not quite as accurate as GPS,
because there are fewer satellites in view at any given time.

I don't want to quote exact timing numbers here, because they depend a lot
on system integration details, but you can easily steer an OCXO within a
few hundred nanoseconds of USNO time. With a rubidium, you can do
considerably better.

If you want to know more, our website is www.satellesinc.com.

(If this message has been too commercial, I apologize in advance. The
boundary between information and salesmanship is not always sharp.)

Cheers!
--Stu

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Hi > On Aug 9, 2020, at 7:03 PM, Tom Van Baak <tvb@LeapSecond.com> wrote: > > Hi Stu, > > There's no problem with a semi-commercial posting here. You've been a member for a decade and frequent contributor plus the subject matter is exactly on-topic. So thanks for posting. > > I spent a while on your web site and didn't uncover a trove of white papers. If you could post some URL's that would be appreciated. You don't have to worry about being less accurate than GPS. I mean, there are often far more important factors than nanosecond precision. To that point ( as accurate as GPS ) ….. GPS is simply a convent comparison system. Saying that this or that is better or worse at this or that tau is *not* the same as saying it has more or less value. It’s simply a system that is out there to be compared to. Bob > You didn't mention pricing; it's hard to imagine it's as free as GPS so that seems like another disadvantage to me. > > Your comment about fewer satellites is spot on. That will be taken care of if you give SpaceX / Starlink a call and join that bandwagon. There are already 597 Starlink [1] satellites up there vs. 82 Iridium [2] satellites, yes? > > If you have entry-level / hobbyist grade evaluation kits I'm sure a number of us would be very interested to try it out. > > Thanks, > /tvb > > [1] https://en.wikipedia.org/wiki/Starlink > > [2] https://en.wikipedia.org/wiki/Iridium_satellite_constellation > > > On 8/9/2020 2:53 PM, Stewart Cobb wrote: >> Taka Kamiya and Forrest Christian both asked recently about the alternative >> satellite PNT system using the Iridium satellites. That system was >> developed by my company, Satelles. It has been commercially available for >> more than a year now. >> >> The biggest advantage is that our signal is at least 30 dB stronger than >> GNSS signals (the exact numbers depend on whether you're talking to >> engineering or marketing :). You can easily get a usable signal in deep >> jungle, or a data center in the middle of a building's basement, or even >> inside a locked shipping container. The stronger signal is correspondingly >> more difficult to jam or spoof than GNSS, and our signal has anti-spoofing >> features as well. >> >> The biggest disadvantage is that it is not quite as accurate as GPS, >> because there are fewer satellites in view at any given time. >> >> I don't want to quote exact timing numbers here, because they depend a lot >> on system integration details, but you can easily steer an OCXO within a >> few hundred nanoseconds of USNO time. With a rubidium, you can do >> considerably better. >> >> If you want to know more, our website is www.satellesinc.com. >> >> (If this message has been too commercial, I apologize in advance. The >> boundary between information and salesmanship is not always sharp.) >> >> Cheers! >> --Stu >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

TK

Taka Kamiya

Mon, Aug 10, 2020 1:33 AM

I've done some quick research. I do not see timing as one of the services provided. I wonder if it can be achieved by just listening into what's already transmitted (like GPS) and do some math on our side.

On more broader sense, was GPS originally designed to provide timing service? Or is it a byproduct of needing to measure location and speed, thus it needed a constant signal, and that using it to sync reference signal is just an ancillary and after-thought use cases?

(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG

On Sunday, August 9, 2020, 9:21:23 PM EDT, Bob kb8tq <kb8tq@n1k.org> wrote:

Hi

On Aug 9, 2020, at 7:03 PM, Tom Van Baak tvb@LeapSecond.com wrote:

Hi Stu,

There's no problem with a semi-commercial posting here. You've been a member for a decade and frequent contributor plus the subject matter is exactly on-topic. So thanks for posting.

I spent a while on your web site and didn't uncover a trove of white papers. If you could post some URL's that would be appreciated. You don't have to worry about being less accurate than GPS. I mean, there are often far more important factors than nanosecond precision.

To that point ( as accurate as GPS ) ….. GPS is simply a convent comparison system. Saying that
this or that is better or worse at this or that tau is not the same as saying it has more or less value.
It’s simply a system that is out there to be compared to.

Bob

You didn't mention pricing; it's hard to imagine it's as free as GPS so that seems like another disadvantage to me.

Your comment about fewer satellites is spot on. That will be taken care of if you give SpaceX / Starlink a call and join that bandwagon. There are already 597 Starlink [1] satellites up there vs. 82 Iridium [2] satellites, yes?

If you have entry-level / hobbyist grade evaluation kits I'm sure a number of us would be very interested to try it out.

Thanks,
/tvb

[1] https://en.wikipedia.org/wiki/Starlink

[2] https://en.wikipedia.org/wiki/Iridium_satellite_constellation

On 8/9/2020 2:53 PM, Stewart Cobb wrote:

Taka Kamiya and Forrest Christian both asked recently about the alternative
satellite PNT system using the Iridium satellites. That system was
developed by my company, Satelles. It has been commercially available for
more than a year now.

The biggest advantage is that our signal is at least 30 dB stronger than
GNSS signals (the exact numbers depend on whether you're talking to
engineering or marketing :). You can easily get a usable signal in deep
jungle, or a data center in the middle of a building's basement, or even
inside a locked shipping container. The stronger signal is correspondingly
more difficult to jam or spoof than GNSS, and our signal has anti-spoofing
features as well.

The biggest disadvantage is that it is not quite as accurate as GPS,
because there are fewer satellites in view at any given time.

I don't want to quote exact timing numbers here, because they depend a lot
on system integration details, but you can easily steer an OCXO within a
few hundred nanoseconds of USNO time. With a rubidium, you can do
considerably better.

If you want to know more, our website is www.satellesinc.com.

(If this message has been too commercial, I apologize in advance. The
boundary between information and salesmanship is not always sharp.)

Cheers!
--Stu

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

I've done some quick research. I do not see timing as one of the services provided. I wonder if it can be achieved by just listening into what's already transmitted (like GPS) and do some math on our side. On more broader sense, was GPS originally designed to provide timing service? Or is it a byproduct of needing to measure location and speed, thus it needed a constant signal, and that using it to sync reference signal is just an ancillary and after-thought use cases? --------------------------------------- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG On Sunday, August 9, 2020, 9:21:23 PM EDT, Bob kb8tq <kb8tq@n1k.org> wrote: Hi > On Aug 9, 2020, at 7:03 PM, Tom Van Baak <tvb@LeapSecond.com> wrote: > > Hi Stu, > > There's no problem with a semi-commercial posting here. You've been a member for a decade and frequent contributor plus the subject matter is exactly on-topic. So thanks for posting. > > I spent a while on your web site and didn't uncover a trove of white papers. If you could post some URL's that would be appreciated. You don't have to worry about being less accurate than GPS. I mean, there are often far more important factors than nanosecond precision. To that point ( as accurate as GPS ) ….. GPS is simply a convent comparison system. Saying that this or that is better or worse at this or that tau is *not* the same as saying it has more or less value. It’s simply a system that is out there to be compared to. Bob > You didn't mention pricing; it's hard to imagine it's as free as GPS so that seems like another disadvantage to me. > > Your comment about fewer satellites is spot on. That will be taken care of if you give SpaceX / Starlink a call and join that bandwagon. There are already 597 Starlink [1] satellites up there vs. 82 Iridium [2] satellites, yes? > > If you have entry-level / hobbyist grade evaluation kits I'm sure a number of us would be very interested to try it out. > > Thanks, > /tvb > > [1] https://en.wikipedia.org/wiki/Starlink > > [2] https://en.wikipedia.org/wiki/Iridium_satellite_constellation > > > On 8/9/2020 2:53 PM, Stewart Cobb wrote: >> Taka Kamiya and Forrest Christian both asked recently about the alternative >> satellite PNT system using the Iridium satellites. That system was >> developed by my company, Satelles. It has been commercially available for >> more than a year now. >> >> The biggest advantage is that our signal is at least 30 dB stronger than >> GNSS signals (the exact numbers depend on whether you're talking to >> engineering or marketing :). You can easily get a usable signal in deep >> jungle, or a data center in the middle of a building's basement, or even >> inside a locked shipping container. The stronger signal is correspondingly >> more difficult to jam or spoof than GNSS, and our signal has anti-spoofing >> features as well. >> >> The biggest disadvantage is that it is not quite as accurate as GPS, >> because there are fewer satellites in view at any given time. >> >> I don't want to quote exact timing numbers here, because they depend a lot >> on system integration details, but you can easily steer an OCXO within a >> few hundred nanoseconds of USNO time. With a rubidium, you can do >> considerably better. >> >> If you want to know more, our website is www.satellesinc.com. >> >> (If this message has been too commercial, I apologize in advance. The >> boundary between information and salesmanship is not always sharp.) >> >> Cheers! >> --Stu >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.

MW

Michael Wouters

Mon, Aug 10, 2020 3:03 AM

Dear Tom,

A one year, single device licence to access the signal cost about AUD10K
when I asked about a year ago. The plugin card for a commercial timing box
was about AUD3K.

Cheers
Michael

On Mon, 10 Aug 2020 at 9:05 am, Tom Van Baak tvb@leapsecond.com wrote:

Hi Stu,

There's no problem with a semi-commercial posting here. You've been a
member for a decade and frequent contributor plus the subject matter is
exactly on-topic. So thanks for posting.

I spent a while on your web site and didn't uncover a trove of white
papers. If you could post some URL's that would be appreciated. You
don't have to worry about being less accurate than GPS. I mean, there
are often far more important factors than nanosecond precision. You
didn't mention pricing; it's hard to imagine it's as free as GPS so that
seems like another disadvantage to me.

Your comment about fewer satellites is spot on. That will be taken care
of if you give SpaceX / Starlink a call and join that bandwagon. There
are already 597 Starlink [1] satellites up there vs. 82 Iridium [2]
satellites, yes?

If you have entry-level / hobbyist grade evaluation kits I'm sure a
number of us would be very interested to try it out.

Thanks,
/tvb

[1] https://en.wikipedia.org/wiki/Starlink

[2] https://en.wikipedia.org/wiki/Iridium_satellite_constellation

On 8/9/2020 2:53 PM, Stewart Cobb wrote:

Taka Kamiya and Forrest Christian both asked recently about the

alternative

satellite PNT system using the Iridium satellites. That system was
developed by my company, Satelles. It has been commercially available for
more than a year now.

The biggest advantage is that our signal is at least 30 dB stronger than
GNSS signals (the exact numbers depend on whether you're talking to
engineering or marketing :). You can easily get a usable signal in deep
jungle, or a data center in the middle of a building's basement, or even
inside a locked shipping container. The stronger signal is

correspondingly

more difficult to jam or spoof than GNSS, and our signal has

anti-spoofing

features as well.

The biggest disadvantage is that it is not quite as accurate as GPS,
because there are fewer satellites in view at any given time.

I don't want to quote exact timing numbers here, because they depend a

lot

on system integration details, but you can easily steer an OCXO within a
few hundred nanoseconds of USNO time. With a rubidium, you can do
considerably better.

If you want to know more, our website is www.satellesinc.com.

(If this message has been too commercial, I apologize in advance. The
boundary between information and salesmanship is not always sharp.)

Cheers!
--Stu

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to

http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com

and follow the instructions there.

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Dear Tom, A one year, single device licence to access the signal cost about AUD10K when I asked about a year ago. The plugin card for a commercial timing box was about AUD3K. Cheers Michael On Mon, 10 Aug 2020 at 9:05 am, Tom Van Baak <tvb@leapsecond.com> wrote: > Hi Stu, > > There's no problem with a semi-commercial posting here. You've been a > member for a decade and frequent contributor plus the subject matter is > exactly on-topic. So thanks for posting. > > I spent a while on your web site and didn't uncover a trove of white > papers. If you could post some URL's that would be appreciated. You > don't have to worry about being less accurate than GPS. I mean, there > are often far more important factors than nanosecond precision. You > didn't mention pricing; it's hard to imagine it's as free as GPS so that > seems like another disadvantage to me. > > Your comment about fewer satellites is spot on. That will be taken care > of if you give SpaceX / Starlink a call and join that bandwagon. There > are already 597 Starlink [1] satellites up there vs. 82 Iridium [2] > satellites, yes? > > If you have entry-level / hobbyist grade evaluation kits I'm sure a > number of us would be very interested to try it out. > > Thanks, > /tvb > > [1] https://en.wikipedia.org/wiki/Starlink > > [2] https://en.wikipedia.org/wiki/Iridium_satellite_constellation > > > On 8/9/2020 2:53 PM, Stewart Cobb wrote: > > Taka Kamiya and Forrest Christian both asked recently about the > alternative > > satellite PNT system using the Iridium satellites. That system was > > developed by my company, Satelles. It has been commercially available for > > more than a year now. > > > > The biggest advantage is that our signal is at least 30 dB stronger than > > GNSS signals (the exact numbers depend on whether you're talking to > > engineering or marketing :). You can easily get a usable signal in deep > > jungle, or a data center in the middle of a building's basement, or even > > inside a locked shipping container. The stronger signal is > correspondingly > > more difficult to jam or spoof than GNSS, and our signal has > anti-spoofing > > features as well. > > > > The biggest disadvantage is that it is not quite as accurate as GPS, > > because there are fewer satellites in view at any given time. > > > > I don't want to quote exact timing numbers here, because they depend a > lot > > on system integration details, but you can easily steer an OCXO within a > > few hundred nanoseconds of USNO time. With a rubidium, you can do > > considerably better. > > > > If you want to know more, our website is www.satellesinc.com. > > > > (If this message has been too commercial, I apologize in advance. The > > boundary between information and salesmanship is not always sharp.) > > > > Cheers! > > --Stu > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. >

TV

Tom Van Baak

Mon, Aug 10, 2020 3:41 AM

Hi Taka,

On more broader sense, was GPS originally designed to provide timing

service?

Yes, from the beginning GPS was a so-called PNT (Positioning, Navigation
and Timing) system.

Or is it a byproduct of needing to measure location and speed, thus it
needed a constant signal, and that using it to sync reference signal
is just an ancillary and after-thought use cases?

Precise timing is not so much a by-product but the key feature that
makes GPS work.

Here's some reading, with an emphasis on the early history and design of
GPS:

"TIMATION - a GPS Predecessor Program"
https://directory.eoportal.org/web/eoportal/satellite-missions/t/timation

"Pre GPS History of Satellite Navigation", Francis M. Czopek
https://web.stanford.edu/group/scpnt/pnt/PNT08/Presentations/2_Czopek_PNT_2008.pdf

"True Origins and Major Original Challenges for GPS Success (1962 –
1978)", Brad Parkinson
https://web.stanford.edu/group/scpnt/pnt/PNT09/presentation_slides/13_Parkinson_Creating_GPS.pdf

"Launching the Brick Moon: GPS’ path from the Space Race to Smartphone",
Aaron Lovell
https://www.wilsonquarterly.com/quarterly/summer-2015-an-age-of-connectivity/launching-the-brick-moon-gps-path-from-the-space-race-to-smartphone/

"GPS Declassified: From Smart Bombs to Smartphones", Richard Easton
http://www.gpsdeclassified.com

"The Origins of GPS", Stephen T. Powers, Brad Parkinson
Article published in May & June 2010 issues of GPS World
https://www.u-blox.com/sites/default/files/the_origins_of_gps.pdf

"Initial Results of the NAVSTAR GPS NTS-2 Satellite", James A Buisson,
Roger L. Easton, Thomas B. McCaskill
"General Relativity in the Global Positioning System", Neil Ashby
http://www.leapsecond.com/history/Ashby-Relativity.htm

/tvb

On 8/9/2020 6:33 PM, Taka Kamiya via time-nuts wrote:

I've done some quick research. I do not see timing as one of the services provided. I wonder if it can be achieved by just listening into what's already transmitted (like GPS) and do some math on our side.

On more broader sense, was GPS originally designed to provide timing service? Or is it a byproduct of needing to measure location and speed, thus it needed a constant signal, and that using it to sync reference signal is just an ancillary and after-thought use cases?

(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG

  On Sunday, August 9, 2020, 9:21:23 PM EDT, Bob kb8tq<kb8tq@n1k.org>  wrote:

Hi

On Aug 9, 2020, at 7:03 PM, Tom Van Baaktvb@LeapSecond.com wrote:

Hi Stu,

There's no problem with a semi-commercial posting here. You've been a member for a decade and frequent contributor plus the subject matter is exactly on-topic. So thanks for posting.

I spent a while on your web site and didn't uncover a trove of white papers. If you could post some URL's that would be appreciated. You don't have to worry about being less accurate than GPS. I mean, there are often far more important factors than nanosecond precision.

To that point ( as accurate as GPS ) ….. GPS is simply a convent comparison system. Saying that
this or that is better or worse at this or that tau is not the same as saying it has more or less value.
It’s simply a system that is out there to be compared to.

Bob

You didn't mention pricing; it's hard to imagine it's as free as GPS so that seems like another disadvantage to me.

Your comment about fewer satellites is spot on. That will be taken care of if you give SpaceX / Starlink a call and join that bandwagon. There are already 597 Starlink [1] satellites up there vs. 82 Iridium [2] satellites, yes?

If you have entry-level / hobbyist grade evaluation kits I'm sure a number of us would be very interested to try it out.

Thanks,
/tvb

[1]https://en.wikipedia.org/wiki/Starlink

[2]https://en.wikipedia.org/wiki/Iridium_satellite_constellation

On 8/9/2020 2:53 PM, Stewart Cobb wrote:

Taka Kamiya and Forrest Christian both asked recently about the alternative
satellite PNT system using the Iridium satellites. That system was
developed by my company, Satelles. It has been commercially available for
more than a year now.

The biggest advantage is that our signal is at least 30 dB stronger than
GNSS signals (the exact numbers depend on whether you're talking to
engineering or marketing :). You can easily get a usable signal in deep
jungle, or a data center in the middle of a building's basement, or even
inside a locked shipping container. The stronger signal is correspondingly
more difficult to jam or spoof than GNSS, and our signal has anti-spoofing
features as well.

The biggest disadvantage is that it is not quite as accurate as GPS,
because there are fewer satellites in view at any given time.

I don't want to quote exact timing numbers here, because they depend a lot
on system integration details, but you can easily steer an OCXO within a
few hundred nanoseconds of USNO time. With a rubidium, you can do
considerably better.

If you want to know more, our website iswww.satellesinc.com.

(If this message has been too commercial, I apologize in advance. The
boundary between information and salesmanship is not always sharp.)

Cheers!
--Stu

time-nuts mailing list --time-nuts@lists.febo.com
To unsubscribe, go tohttp://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Hi Taka, > On more broader sense, was GPS originally designed to provide timing service? Yes, from the beginning GPS was a so-called PNT (Positioning, Navigation and Timing) system. > Or is it a byproduct of needing to measure location and speed, thus it > needed a constant signal, and that using it to sync reference signal > is just an ancillary and after-thought use cases? Precise timing is not so much a by-product but the key feature that makes GPS work. Here's some reading, with an emphasis on the early history and design of GPS: "TIMATION - a GPS Predecessor Program" https://directory.eoportal.org/web/eoportal/satellite-missions/t/timation "Pre GPS History of Satellite Navigation", Francis M. Czopek https://web.stanford.edu/group/scpnt/pnt/PNT08/Presentations/2_Czopek_PNT_2008.pdf "True Origins and Major Original Challenges for GPS Success (1962 – 1978)", Brad Parkinson https://web.stanford.edu/group/scpnt/pnt/PNT09/presentation_slides/13_Parkinson_Creating_GPS.pdf "Launching the Brick Moon: GPS’ path from the Space Race to Smartphone", Aaron Lovell https://www.wilsonquarterly.com/quarterly/summer-2015-an-age-of-connectivity/launching-the-brick-moon-gps-path-from-the-space-race-to-smartphone/ "GPS Declassified: From Smart Bombs to Smartphones", Richard Easton http://www.gpsdeclassified.com "The Origins of GPS", Stephen T. Powers, Brad Parkinson Article published in May & June 2010 issues of GPS World https://www.u-blox.com/sites/default/files/the_origins_of_gps.pdf "Initial Results of the NAVSTAR GPS NTS-2 Satellite", James A Buisson, Roger L. Easton, Thomas B. McCaskill "General Relativity in the Global Positioning System", Neil Ashby http://www.leapsecond.com/history/Ashby-Relativity.htm /tvb On 8/9/2020 6:33 PM, Taka Kamiya via time-nuts wrote: > I've done some quick research. I do not see timing as one of the services provided. I wonder if it can be achieved by just listening into what's already transmitted (like GPS) and do some math on our side. > > On more broader sense, was GPS originally designed to provide timing service? Or is it a byproduct of needing to measure location and speed, thus it needed a constant signal, and that using it to sync reference signal is just an ancillary and after-thought use cases? > > --------------------------------------- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > > > On Sunday, August 9, 2020, 9:21:23 PM EDT, Bob kb8tq<kb8tq@n1k.org> wrote: > > Hi > > > >> On Aug 9, 2020, at 7:03 PM, Tom Van Baak<tvb@LeapSecond.com> wrote: >> >> Hi Stu, >> >> There's no problem with a semi-commercial posting here. You've been a member for a decade and frequent contributor plus the subject matter is exactly on-topic. So thanks for posting. >> >> I spent a while on your web site and didn't uncover a trove of white papers. If you could post some URL's that would be appreciated. You don't have to worry about being less accurate than GPS. I mean, there are often far more important factors than nanosecond precision. > To that point ( as accurate as GPS ) ….. GPS is simply a convent comparison system. Saying that > this or that is better or worse at this or that tau is *not* the same as saying it has more or less value. > It’s simply a system that is out there to be compared to. > > Bob > > >> You didn't mention pricing; it's hard to imagine it's as free as GPS so that seems like another disadvantage to me. >> >> Your comment about fewer satellites is spot on. That will be taken care of if you give SpaceX / Starlink a call and join that bandwagon. There are already 597 Starlink [1] satellites up there vs. 82 Iridium [2] satellites, yes? >> >> If you have entry-level / hobbyist grade evaluation kits I'm sure a number of us would be very interested to try it out. >> >> Thanks, >> /tvb >> >> [1]https://en.wikipedia.org/wiki/Starlink >> >> [2]https://en.wikipedia.org/wiki/Iridium_satellite_constellation >> >> >> On 8/9/2020 2:53 PM, Stewart Cobb wrote: >>> Taka Kamiya and Forrest Christian both asked recently about the alternative >>> satellite PNT system using the Iridium satellites. That system was >>> developed by my company, Satelles. It has been commercially available for >>> more than a year now. >>> >>> The biggest advantage is that our signal is at least 30 dB stronger than >>> GNSS signals (the exact numbers depend on whether you're talking to >>> engineering or marketing :). You can easily get a usable signal in deep >>> jungle, or a data center in the middle of a building's basement, or even >>> inside a locked shipping container. The stronger signal is correspondingly >>> more difficult to jam or spoof than GNSS, and our signal has anti-spoofing >>> features as well. >>> >>> The biggest disadvantage is that it is not quite as accurate as GPS, >>> because there are fewer satellites in view at any given time. >>> >>> I don't want to quote exact timing numbers here, because they depend a lot >>> on system integration details, but you can easily steer an OCXO within a >>> few hundred nanoseconds of USNO time. With a rubidium, you can do >>> considerably better. >>> >>> If you want to know more, our website iswww.satellesinc.com. >>> >>> (If this message has been too commercial, I apologize in advance. The >>> boundary between information and salesmanship is not always sharp.) >>> >>> Cheers! >>> --Stu >>> _______________________________________________ >>> time-nuts mailing list --time-nuts@lists.febo.com >>> To unsubscribe, go tohttp://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>> and follow the instructions there. >>> >> _______________________________________________ >> time-nuts mailing list --time-nuts@lists.febo.com >> To unsubscribe, go tohttp://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > _______________________________________________ > time-nuts mailing list --time-nuts@lists.febo.com > To unsubscribe, go tohttp://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list --time-nuts@lists.febo.com > To unsubscribe, go tohttp://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

JM

John Maxwell

Mon, Aug 10, 2020 3:51 AM

On 08/09/2020 09:33:07 PM, Taka Kamiya via time-nuts wrote:
[snip]

On more broader sense, was GPS originally designed to provide timing
service? Or is it a byproduct of needing to measure location and
speed, thus it needed a constant signal, and that using it to sync
reference signal is just an ancillary and after-thought use cases?

A little of both. The desire on the customer's part (i.e., what the US
military wanted) was accurate rapidly updatable location information.
But the approach used for GPS also required the receiver to precisely
compute the time as well.

So, it wasn't in the requirements, but it is inherent in the design.

-John

--
John Maxwell KB3VLL jmax@jmaxhome.com

On 08/09/2020 09:33:07 PM, Taka Kamiya via time-nuts wrote: [snip] > On more broader sense, was GPS originally designed to provide timing > service? Or is it a byproduct of needing to measure location and > speed, thus it needed a constant signal, and that using it to sync > reference signal is just an ancillary and after-thought use cases? A little of both. The desire on the customer's part (i.e., what the US military wanted) was accurate rapidly updatable location information. But the approach used for GPS also required the receiver to precisely compute the time as well. So, it wasn't in the requirements, but it is inherent in the design. -John -- John Maxwell KB3VLL jmax@jmaxhome.com

E

ew

Mon, Aug 10, 2020 9:09 AM

Attached are two pictures from my TI days as program Manager of the first GPS. There was no discussions of consumer use or timing application. Focus was on military application being able to guide a bomb in to a chimney. The cost per device was $ 300 000. Because of my high security clearance I was asked to brief the NSA and CIA on the future of GPS equipment. With my semiconductor background Moores Law and previously involved in consumer calculator development I predicted the size of a brick and $ 3000. I was declared the company Idiot lost all credibility as a strategic thinker ans subsequently left TI. When Magellan came out with there handheld unit they remembered me and send me one. Still have it. When two years later the units the size of a cigarette pack came out and where given away if you took a Cadillac test drive the asked for it back. I refused. History.Bert Kehren In a message dated 8/9/2020 11:23:33 PM Eastern Standard Time, time-nuts@lists.febo.com writes:
I've done some quick research. I do not see timing as one of the services provided. I wonder if it can be achieved by just listening into what's already transmitted (like GPS) and do some math on our side.

On more broader sense, was GPS originally designed to provide timing service? Or is it a byproduct of needing to measure location and speed, thus it needed a constant signal, and that using it to sync reference signal is just an ancillary and after-thought use cases?

(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG

On Sunday, August 9, 2020, 9:21:23 PM EDT, Bob kb8tq kb8tq@n1k.org wrote:

Hi

On Aug 9, 2020, at 7:03 PM, Tom Van Baak tvb@LeapSecond.com wrote:

Hi Stu,

There's no problem with a semi-commercial posting here. You've been a member for a decade and frequent contributor plus the subject matter is exactly on-topic. So thanks for posting.

I spent a while on your web site and didn't uncover a trove of white papers. If you could post some URL's that would be appreciated. You don't have to worry about being less accurate than GPS. I mean, there are often far more important factors than nanosecond precision.

To that point ( as accurate as GPS ) ….. GPS is simply a convent comparison system. Saying that
this or that is better or worse at this or that tau is not the same as saying it has more or less value.
It’s simply a system that is out there to be compared to.

Bob

You didn't mention pricing; it's hard to imagine it's as free as GPS so that seems like another disadvantage to me.

Your comment about fewer satellites is spot on. That will be taken care of if you give SpaceX / Starlink a call and join that bandwagon. There are already 597 Starlink [1] satellites up there vs. 82 Iridium [2] satellites, yes?

If you have entry-level / hobbyist grade evaluation kits I'm sure a number of us would be very interested to try it out.

Thanks,
/tvb

[1] https://en.wikipedia.org/wiki/Starlink

[2] https://en.wikipedia.org/wiki/Iridium_satellite_constellation

On 8/9/2020 2:53 PM, Stewart Cobb wrote:

Taka Kamiya and Forrest Christian both asked recently about the alternative
satellite PNT system using the Iridium satellites. That system was
developed by my company, Satelles. It has been commercially available for
more than a year now.

The biggest advantage is that our signal is at least 30 dB stronger than
GNSS signals (the exact numbers depend on whether you're talking to
engineering or marketing :). You can easily get a usable signal in deep
jungle, or a data center in the middle of a building's basement, or even
inside a locked shipping container. The stronger signal is correspondingly
more difficult to jam or spoof than GNSS, and our signal has anti-spoofing
features as well.

The biggest disadvantage is that it is not quite as accurate as GPS,
because there are fewer satellites in view at any given time.

I don't want to quote exact timing numbers here, because they depend a lot
on system integration details, but you can easily steer an OCXO within a
few hundred nanoseconds of USNO time. With a rubidium, you can do
considerably better.

If you want to know more, our website is www.satellesinc.com.

(If this message has been too commercial, I apologize in advance. The
boundary between information and salesmanship is not always sharp.)

Cheers!
--Stu

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Attached are two pictures from my TI days as program Manager of the first GPS. There was no discussions of consumer use or timing application. Focus was on military application being able to guide a bomb in to a chimney. The cost per device was $ 300 000. Because of my high security clearance I was asked to brief the NSA and CIA on the future of GPS equipment. With my semiconductor background Moores Law and previously involved in consumer calculator development I predicted the size of a brick and $ 3000. I was declared the company Idiot lost all credibility as a strategic thinker ans subsequently left TI. When Magellan came out with there handheld unit they remembered me and send me one. Still have it. When two years later the units the size of a cigarette pack came out and where given away if you took a Cadillac test drive the asked for it back. I refused. History.Bert Kehren In a message dated 8/9/2020 11:23:33 PM Eastern Standard Time, time-nuts@lists.febo.com writes: I've done some quick research. I do not see timing as one of the services provided. I wonder if it can be achieved by just listening into what's already transmitted (like GPS) and do some math on our side. On more broader sense, was GPS originally designed to provide timing service? Or is it a byproduct of needing to measure location and speed, thus it needed a constant signal, and that using it to sync reference signal is just an ancillary and after-thought use cases? --------------------------------------- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG On Sunday, August 9, 2020, 9:21:23 PM EDT, Bob kb8tq <kb8tq@n1k.org> wrote: Hi > On Aug 9, 2020, at 7:03 PM, Tom Van Baak <tvb@LeapSecond.com> wrote: > > Hi Stu, > > There's no problem with a semi-commercial posting here. You've been a member for a decade and frequent contributor plus the subject matter is exactly on-topic. So thanks for posting. > > I spent a while on your web site and didn't uncover a trove of white papers. If you could post some URL's that would be appreciated. You don't have to worry about being less accurate than GPS. I mean, there are often far more important factors than nanosecond precision. To that point ( as accurate as GPS ) ….. GPS is simply a convent comparison system. Saying that this or that is better or worse at this or that tau is *not* the same as saying it has more or less value. It’s simply a system that is out there to be compared to. Bob > You didn't mention pricing; it's hard to imagine it's as free as GPS so that seems like another disadvantage to me. > > Your comment about fewer satellites is spot on. That will be taken care of if you give SpaceX / Starlink a call and join that bandwagon. There are already 597 Starlink [1] satellites up there vs. 82 Iridium [2] satellites, yes? > > If you have entry-level / hobbyist grade evaluation kits I'm sure a number of us would be very interested to try it out. > > Thanks, > /tvb > > [1] https://en.wikipedia.org/wiki/Starlink > > [2] https://en.wikipedia.org/wiki/Iridium_satellite_constellation > > > On 8/9/2020 2:53 PM, Stewart Cobb wrote: >> Taka Kamiya and Forrest Christian both asked recently about the alternative >> satellite PNT system using the Iridium satellites. That system was >> developed by my company, Satelles. It has been commercially available for >> more than a year now. >> >> The biggest advantage is that our signal is at least 30 dB stronger than >> GNSS signals (the exact numbers depend on whether you're talking to >> engineering or marketing :). You can easily get a usable signal in deep >> jungle, or a data center in the middle of a building's basement, or even >> inside a locked shipping container. The stronger signal is correspondingly >> more difficult to jam or spoof than GNSS, and our signal has anti-spoofing >> features as well. >> >> The biggest disadvantage is that it is not quite as accurate as GPS, >> because there are fewer satellites in view at any given time. >> >> I don't want to quote exact timing numbers here, because they depend a lot >> on system integration details, but you can easily steer an OCXO within a >> few hundred nanoseconds of USNO time. With a rubidium, you can do >> considerably better. >> >> If you want to know more, our website is www.satellesinc.com. >> >> (If this message has been too commercial, I apologize in advance. The >> boundary between information and salesmanship is not always sharp.) >> >> Cheers! >> --Stu >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.

BK

Bob kb8tq

Mon, Aug 10, 2020 2:40 PM

Hi

From what I saw as the system was developed, the people doing it realized that timing
was at the core of the design. If there was a timing problem, nothing was going to work.
There were GPS (and before that other sat-nav) presentations at the Frequency Control
Symposium for many years. The “big boys” in timing all were involved in GPS one way
or the other.

NIST was doing time transfer work on GPS before the system was fully up and running.
Their results are (to a great degree) what got everybody believing that GPS could
be a good source of time. Those papers started early and kept on flowing …. Until they
put their “stamp of approval” on the technique, I don’t think anybody was ready to call it
a super time source.

This is by no means to imply that NIST was the only outfit involved or that the others
who also evaluated GPS somehow did not contribute. That’s far from the case. The only
point is that NIST got out there early.

Bob

On Aug 10, 2020, at 5:09 AM, ew via time-nuts time-nuts@lists.febo.com wrote:

Attached are two pictures from my TI days as program Manager of the first GPS. There was no discussions of consumer use or timing application. Focus was on military application being able to guide a bomb in to a chimney. The cost per device was $ 300 000. Because of my high security clearance I was asked to brief the NSA and CIA on the future of GPS equipment. With my semiconductor background Moores Law and previously involved in consumer calculator development I predicted the size of a brick and $ 3000. I was declared the company Idiot lost all credibility as a strategic thinker ans subsequently left TI. When Magellan came out with there handheld unit they remembered me and send me one. Still have it. When two years later the units the size of a cigarette pack came out and where given away if you took a Cadillac test drive the asked for it back. I refused. History.Bert Kehren In a message dated 8/9/2020 11:23:33 PM Eastern Standard Time, time-nuts@lists.febo.com writes:
I've done some quick research. I do not see timing as one of the services provided. I wonder if it can be achieved by just listening into what's already transmitted (like GPS) and do some math on our side.

On more broader sense, was GPS originally designed to provide timing service? Or is it a byproduct of needing to measure location and speed, thus it needed a constant signal, and that using it to sync reference signal is just an ancillary and after-thought use cases?

(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG

 On Sunday, August 9, 2020, 9:21:23 PM EDT, Bob kb8tq <kb8tq@n1k.org> wrote:

Hi

On Aug 9, 2020, at 7:03 PM, Tom Van Baak tvb@LeapSecond.com wrote:

Hi Stu,

There's no problem with a semi-commercial posting here. You've been a member for a decade and frequent contributor plus the subject matter is exactly on-topic. So thanks for posting.

I spent a while on your web site and didn't uncover a trove of white papers. If you could post some URL's that would be appreciated. You don't have to worry about being less accurate than GPS. I mean, there are often far more important factors than nanosecond precision.

To that point ( as accurate as GPS ) ….. GPS is simply a convent comparison system. Saying that
this or that is better or worse at this or that tau is not the same as saying it has more or less value.
It’s simply a system that is out there to be compared to.

Bob

You didn't mention pricing; it's hard to imagine it's as free as GPS so that seems like another disadvantage to me.

Your comment about fewer satellites is spot on. That will be taken care of if you give SpaceX / Starlink a call and join that bandwagon. There are already 597 Starlink [1] satellites up there vs. 82 Iridium [2] satellites, yes?

If you have entry-level / hobbyist grade evaluation kits I'm sure a number of us would be very interested to try it out.

Thanks,
/tvb

[1] https://en.wikipedia.org/wiki/Starlink

[2] https://en.wikipedia.org/wiki/Iridium_satellite_constellation

On 8/9/2020 2:53 PM, Stewart Cobb wrote:

Taka Kamiya and Forrest Christian both asked recently about the alternative
satellite PNT system using the Iridium satellites. That system was
developed by my company, Satelles. It has been commercially available for
more than a year now.

The biggest advantage is that our signal is at least 30 dB stronger than
GNSS signals (the exact numbers depend on whether you're talking to
engineering or marketing :). You can easily get a usable signal in deep
jungle, or a data center in the middle of a building's basement, or even
inside a locked shipping container. The stronger signal is correspondingly
more difficult to jam or spoof than GNSS, and our signal has anti-spoofing
features as well.

The biggest disadvantage is that it is not quite as accurate as GPS,
because there are fewer satellites in view at any given time.

I don't want to quote exact timing numbers here, because they depend a lot
on system integration details, but you can easily steer an OCXO within a
few hundred nanoseconds of USNO time. With a rubidium, you can do
considerably better.

If you want to know more, our website is www.satellesinc.com.

(If this message has been too commercial, I apologize in advance. The
boundary between information and salesmanship is not always sharp.)

Cheers!
--Stu

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.
<First GPS.jpg><Side view GPS.jpg>_______________________________________________
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Hi From what I saw as the system was developed, the people doing it realized that timing was at the core of the design. If there was a timing problem, nothing was going to work. There were GPS (and before that other sat-nav) presentations at the Frequency Control Symposium for many years. The “big boys” in timing all were involved in GPS one way or the other. NIST was doing time transfer work on GPS before the system was fully up and running. Their results are (to a great degree) what got everybody believing that GPS *could* be a good source of time. Those papers started early and kept on flowing …. Until they put their “stamp of approval” on the technique, I don’t think anybody was ready to call it a super time source. This is by no means to imply that NIST was the only outfit involved or that the others who also evaluated GPS somehow did not contribute. That’s far from the case. The only point is that NIST got out there early. Bob > On Aug 10, 2020, at 5:09 AM, ew via time-nuts <time-nuts@lists.febo.com> wrote: > > Attached are two pictures from my TI days as program Manager of the first GPS. There was no discussions of consumer use or timing application. Focus was on military application being able to guide a bomb in to a chimney. The cost per device was $ 300 000. Because of my high security clearance I was asked to brief the NSA and CIA on the future of GPS equipment. With my semiconductor background Moores Law and previously involved in consumer calculator development I predicted the size of a brick and $ 3000. I was declared the company Idiot lost all credibility as a strategic thinker ans subsequently left TI. When Magellan came out with there handheld unit they remembered me and send me one. Still have it. When two years later the units the size of a cigarette pack came out and where given away if you took a Cadillac test drive the asked for it back. I refused. History.Bert Kehren In a message dated 8/9/2020 11:23:33 PM Eastern Standard Time, time-nuts@lists.febo.com writes: > I've done some quick research. I do not see timing as one of the services provided. I wonder if it can be achieved by just listening into what's already transmitted (like GPS) and do some math on our side. > > On more broader sense, was GPS originally designed to provide timing service? Or is it a byproduct of needing to measure location and speed, thus it needed a constant signal, and that using it to sync reference signal is just an ancillary and after-thought use cases? > > --------------------------------------- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > > > On Sunday, August 9, 2020, 9:21:23 PM EDT, Bob kb8tq <kb8tq@n1k.org> wrote: > > Hi > > > >> On Aug 9, 2020, at 7:03 PM, Tom Van Baak <tvb@LeapSecond.com> wrote: >> >> Hi Stu, >> >> There's no problem with a semi-commercial posting here. You've been a member for a decade and frequent contributor plus the subject matter is exactly on-topic. So thanks for posting. >> >> I spent a while on your web site and didn't uncover a trove of white papers. If you could post some URL's that would be appreciated. You don't have to worry about being less accurate than GPS. I mean, there are often far more important factors than nanosecond precision. > > To that point ( as accurate as GPS ) ….. GPS is simply a convent comparison system. Saying that > this or that is better or worse at this or that tau is *not* the same as saying it has more or less value. > It’s simply a system that is out there to be compared to. > > Bob > > >> You didn't mention pricing; it's hard to imagine it's as free as GPS so that seems like another disadvantage to me. >> >> Your comment about fewer satellites is spot on. That will be taken care of if you give SpaceX / Starlink a call and join that bandwagon. There are already 597 Starlink [1] satellites up there vs. 82 Iridium [2] satellites, yes? >> >> If you have entry-level / hobbyist grade evaluation kits I'm sure a number of us would be very interested to try it out. >> >> Thanks, >> /tvb >> >> [1] https://en.wikipedia.org/wiki/Starlink >> >> [2] https://en.wikipedia.org/wiki/Iridium_satellite_constellation >> >> >> On 8/9/2020 2:53 PM, Stewart Cobb wrote: >>> Taka Kamiya and Forrest Christian both asked recently about the alternative >>> satellite PNT system using the Iridium satellites. That system was >>> developed by my company, Satelles. It has been commercially available for >>> more than a year now. >>> >>> The biggest advantage is that our signal is at least 30 dB stronger than >>> GNSS signals (the exact numbers depend on whether you're talking to >>> engineering or marketing :). You can easily get a usable signal in deep >>> jungle, or a data center in the middle of a building's basement, or even >>> inside a locked shipping container. The stronger signal is correspondingly >>> more difficult to jam or spoof than GNSS, and our signal has anti-spoofing >>> features as well. >>> >>> The biggest disadvantage is that it is not quite as accurate as GPS, >>> because there are fewer satellites in view at any given time. >>> >>> I don't want to quote exact timing numbers here, because they depend a lot >>> on system integration details, but you can easily steer an OCXO within a >>> few hundred nanoseconds of USNO time. With a rubidium, you can do >>> considerably better. >>> >>> If you want to know more, our website is www.satellesinc.com. >>> >>> (If this message has been too commercial, I apologize in advance. The >>> boundary between information and salesmanship is not always sharp.) >>> >>> Cheers! >>> --Stu >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@lists.febo.com >>> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>> and follow the instructions there. >>> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > <First GPS.jpg><Side view GPS.jpg>_______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

J

jimlux

Mon, Aug 10, 2020 3:23 PM

On 8/10/20 7:40 AM, Bob kb8tq wrote:

Hi

From what I saw as the system was developed, the people doing it realized that timing
was at the core of the design. If there was a timing problem, nothing was going to work.
There were GPS (and before that other sat-nav) presentations at the Frequency Control
Symposium for many years. The “big boys” in timing all were involved in GPS one way
or the other.

NIST was doing time transfer work on GPS before the system was fully up and running.
Their results are (to a great degree) what got everybody believing that GPS could
be a good source of time. Those papers started early and kept on flowing …. Until they
put their “stamp of approval” on the technique, I don’t think anybody was ready to call it
a super time source.

This is by no means to imply that NIST was the only outfit involved or that the others
who also evaluated GPS somehow did not contribute. That’s far from the case. The only
point is that NIST got out there early.

Bob

The original Woodford/Nakamura report from 1966

http://www.xyht.com/wp-content/uploads/2016/07/3-5-redacted-TOR-10012525-17-1-Briefing-navigation-satellite-study_Redacted.pdf

Very much describes the "requirements" as being able to target something
with an uncertainty of <0.01 nautical Mile (about 20 meters) (the most
stringent one I see) - there's a whole list of accuracy/cadence
requirements on slide 27

They also describe the aspect that it's not necessarily absolute
position that's important, but relative to the target, airport you're
returning to, etc. (implying that cartography and map models also
needed to improve)

They don't really ever say they would be providing "time" per-se
(comparing Loran C,D, Omega, Transit, and future system), but they do
mention (page 47) that Cesium clocks are available.

They go through the trades and show that you need some sort of
"simultaneous" scheme (unlike transit) to accommodate the "high fix
rate" users - and compare angles, range rate, range differencing as the
observables.
Page 57 (attached) is the one everyone's seen with the taxonomy of
various schemes.

Nowhere in the report do they mention time, although they do say that
one could put a system up without cesium clocks and improve it later.

On 8/10/20 7:40 AM, Bob kb8tq wrote: > Hi > > From what I saw as the system was developed, the people doing it realized that timing > was at the core of the design. If there was a timing problem, nothing was going to work. > There were GPS (and before that other sat-nav) presentations at the Frequency Control > Symposium for many years. The “big boys” in timing all were involved in GPS one way > or the other. > > NIST was doing time transfer work on GPS before the system was fully up and running. > Their results are (to a great degree) what got everybody believing that GPS *could* > be a good source of time. Those papers started early and kept on flowing …. Until they > put their “stamp of approval” on the technique, I don’t think anybody was ready to call it > a super time source. > > This is by no means to imply that NIST was the only outfit involved or that the others > who also evaluated GPS somehow did not contribute. That’s far from the case. The only > point is that NIST got out there early. > > Bob > The original Woodford/Nakamura report from 1966 http://www.xyht.com/wp-content/uploads/2016/07/3-5-redacted-TOR-10012525-17-1-Briefing-navigation-satellite-study_Redacted.pdf Very much describes the "requirements" as being able to target something with an uncertainty of <0.01 nautical Mile (about 20 meters) (the most stringent one I see) - there's a whole list of accuracy/cadence requirements on slide 27 They also describe the aspect that it's not necessarily absolute position that's important, but relative to the target, airport you're returning to, etc. (implying that cartography and map models also needed to improve) They don't really ever say they would be providing "time" per-se (comparing Loran C,D, Omega, Transit, and future system), but they do mention (page 47) that Cesium clocks are available. They go through the trades and show that you need some sort of "simultaneous" scheme (unlike transit) to accommodate the "high fix rate" users - and compare angles, range rate, range differencing as the observables. Page 57 (attached) is the one everyone's seen with the taxonomy of various schemes. Nowhere in the report do they mention time, although they do say that one could put a system up without cesium clocks and improve it later.

time-nuts@lists.febo.com

Satelles PNT from Iridium satellites