# Casio RC/GPS watch



## ronalddheld (May 5, 2005)

Casio G-Shock GPW1000 Is First Watch To Combine GPS & Atomic Clock Radio Time Syncing | aBlogtoWatch
Not the primary source but interesting


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## dicioccio (Jul 14, 2011)

Interesting... rather that combining intrinsinc accuracy (from TC) with external reference (RC *OR* GPS), Casio decided to combine 2 different external references (RC *AND* GPS).

While it is a good thing to see an important manufacturer trying new improvements, I don't understand they way chosen by Casio...


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## ronalddheld (May 5, 2005)

How much innovation does it require given that Casio does RC/solar already? Adding another radio is easier than creating a TC module?


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## dicioccio (Jul 14, 2011)

ronalddheld said:


> How much innovation does it require given that Casio does RC/solar already? Adding another radio is easier than creating a TC module?


Of course I am not a Casio researcher / engineer but, as far as I know, it is very hard to think that it's easier to fit a GPS module in a RC module rather than adding a simple TC...


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## petew (Apr 6, 2006)

ronalddheld said:


> How much innovation does it require given that Casio does RC/solar already? Adding another radio is easier than creating a TC module?


I think that from a marketing point of view it's very easy to understand why they chose to go the RC/GPS route rather than TC/RC/GPS route.

Are there any Casio G Shock watch fans that care about TC more than RC and GPS. I seriously doubt it.


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## chris01 (Jan 5, 2011)

One thing that they could certainly have done is to produce a watch that looks like a watch rather than something from Star Wars. Not everybody wanting a high-tech watch is 15 years old.


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## ken_sturrock (Oct 24, 2010)

chris01 said:


> One thing that they could certainly have done is to produce a watch that looks like a watch rather than something from Star Wars. Not everybody wanting a high-tech watch is 15 years old.


Maybe it will make it into an Oceanus case. Marketing aside, I'm with Dicioccio and am still not sold on the twin radio receivers. One for setting position when you're outside and one for inside to tweak it? It may sound sexy to the unknowing but just seems redundant.


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## chris01 (Jan 5, 2011)

We are still in an evolutionary phase where (1) TC is still the only practical autonomous accuracy technology (2) RC fits a normal sized watch and works very well but ONLY if you live, travel and work in the right places (3) GPS is still far too large, expensive, insensitive, and probably power hungry, to be acceptable for most HAQ enthusiasts (4) CSAC is just not ready for prime time  for the same sort of reasons as GPS, but more so.

So there is currently no ideal combination of technologies. TC with RC would be the easiest to do while avoiding the GPS/CSAC problems. Any other combination at present seems either pointless (RC+GPS) or unachievable.

Where are you, Morgenwerk?


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## ronalddheld (May 5, 2005)

Maybe Morgenwerk will surface in the summer???


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## everose (Jan 15, 2010)

I think the combining of RC *and* GPS is to maximise power consumption efficiencies when syncing. Apparently it will attempt to RC sync first and only if that fails it will default to a GPS sync. 

In terms of functionality (feature set) this Casio has certainly upped the bar compared to Seiko Astron and Citizen Satellite Wave- Air.Whilst the styling may not appeal to many people around here, i imagine many G-Shock fans will not be disappointed with its aesthetics.


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## Sabresoft (Dec 1, 2010)

I'm curious about the default RC then GPS sync on fail, because generally RC works best at night, and GPS during daylight hours. 

Still an interesting concept.


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## ken_sturrock (Oct 24, 2010)

Redundant radio receivers aside, the good news (in my opinion) is that the watch will have a sapphire crystal. The bad news (in my opinion) is that the watch will be 56mm wide. 

At least the Seiko Astron GPS chronograph is shrinking slightly (45mm)...


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## webvan (Dec 11, 2008)

56mm, wow! Anyone seen its price?


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## ronalddheld (May 5, 2005)

webvan said:


> 56mm, wow! Anyone seen its price?


Speculation is that it is around 1K USD.


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## webvan (Dec 11, 2008)

Thanks, that's rather pricy...if you don't need hands a Garmin Forerunner is a much better deal and more useful if you're a runner...and a lot more wearable ;-)


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## dicioccio (Jul 14, 2011)

everose said:


> I think the combining of RC *and* GPS is to maximise power consumption efficiencies when syncing. Apparently it will attempt to RC sync first and only if that fails it will default to a GPS sync.
> 
> In terms of functionality (feature set) this Casio has certainly upped the bar compared to Seiko Astron and Citizen Satellite Wave- Air.Whilst the styling may not appeal to many people around here, i imagine many G-Shock fans will not be disappointed with its aesthetics.


If you have an RC signal the GPS is simply useless... At the same time if you don't have and RC signal, GPS is the only way to have an external reference.

I believe that the customer who buy an RC watch knows if he's going to get the RC signal so, assuming that, he already knows if he need RC or GPS and, in general, he won't need them both. Of course a small amount of users will need RC and GPS but it is a very small percentage. Therefore, leaving apart marketing reasons, I am not able to understand the Casio move and, in general, I don't understand why no manufacturer wants to add the TC functionality to an RC module...


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## everose (Jan 15, 2010)

dicioccio said:


> If you have an RC signal the GPS is simply useless... At the same time if you don't have and RC signal, GPS is the only way to have an external reference.
> 
> I believe that the customer who buy an RC watch knows if he's going to get the RC signal so, assuming that, he already knows if he need RC or GPS and, in general, he won't need them both. Of course a small amount of users will need RC and GPS but it is a very small percentage. Therefore, leaving apart marketing reasons, I am not able to understand the Casio move...


I may be a good example for one of their target customers. I spend 3-4 months a year within the good/reliable range of the UK/EU RC towers. (I cannot remember the last time a sync failed, its just so reliable!) The rest of the year i am in places such as SE Asia and I'm well outside the'official' range of all RC towers. (but i sometimes still manage to get infrequent Japan/China RC syncs) A more reliable daily sync would certainly be much more desirable for me.

Sure this is all about extrinsic accuracy but it increases the chances of a daily sync regardless of where you are or where you may go. 
If extrinsic could be 'totally reliable' then for me the advantages of intrinsic would objectively diminish slightly. I think the combining of RC/GPS increases the predictability/reliability of 'a daily sync' and so moves extrinsic tech further down the path towards a 'totally reliable' daily sync. (as compared to RC only or GPS only)
All those living on the periphery of an RC Signal may also be interested in this hybrid sync capability.

If you are well within range of an RC tower and don't travel outside its range so much then, yes, i agree, this tech would probably be redundant. (but if you did happen to fail a sync i guess it would be reassuring to know that the GPS could capture one later that day if you so wished) Just as with buying a GPS watch for timekeeping purposes within a good/reliable RC sync area, perhaps there is objectively little point paying a premium for the GPS timepiece?!! The usefulness (as always) depends on what your particular needs/priorities are.


When this G-Shock RC/GPS was first announced a month or two ago i was also pretty sceptical and thought it sounded rather gimmicky. However for someone like me who travels to some far flung places quite regularly, i think i can appreciate the point of it, more and more. 
Such a watch which also has rugged durability and doesn't look particularly 'high-end' are also features that i find very useful when travelling.

I know many modern G-Shocks are typically rather bulky,..... But approx 56mm!
If they could only work on reducing the size, just as Seiko and Citizen have clearly been working hard at since last year.


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## everose (Jan 15, 2010)

Here is some more info about the 5410 GPS/RC module and the collaboration with Sony.

(Google translate does quite a hatchet job on this one!)
ã‚½ãƒ‹ãƒ¼Ã-ã‚«ã‚·ã‚ª! ä¸-ç•Œåˆ�ã€ŒGPSãƒ�ã‚¤ãƒ-ãƒªãƒƒãƒ‰é›»æ³¢æ™‚è¨ˆã€�ã�®ã‚.ãƒ¼ãƒ‡ãƒ�ã‚¤ã‚¹ã�«è¿«ã‚‹! | å®¶é›» | ãƒžã‚¤ãƒŠãƒ"ãƒ‹ãƒ¥ãƒ¼ã‚¹

(pic from above link)










Here is the Casio Baselworld GPW-1000 webpage.
G-SHOCK - PRODUCTS - BASELWORLD 2014 - CASIO


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## chris01 (Jan 5, 2011)

everose said:


> Here is some more info about the 5410 GPS/RC module and the collaboration with Sony.
> 
> (Google translate does quite a hatchet job on this one!)
> ã‚½ãƒ‹ãƒ¼Ã-ã‚«ã‚·ã‚ª! ä¸-ç•Œåˆ�ã€ŒGPSãƒ�ã‚¤ãƒ-ãƒªãƒƒãƒ‰é›»æ³¢æ™‚è¨ˆã€�ã�®ã‚.ãƒ¼ãƒ‡ãƒ�ã‚¤ã‚¹ã�«è¿«ã‚‹! | å®¶é›» | ãƒžã‚¤ãƒŠãƒ"ãƒ‹ãƒ¥ãƒ¼ã‚¹
> ...


Google Chrome makes a fair attempt at translation. 
8 months in the dark isn't bad, but I guess there won't be many GPS syncs during that time.
Now, Casio, just put it in a decent case, please.


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## ronalddheld (May 5, 2005)

Decent case and display would be my request.


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## everose (Jan 15, 2010)

chris01 said:


> 8 months in the dark isn't bad...


I agree. As a comparison my standard Radio Controlled GW-7900B has a PR of approx 9 months without power saving engaged.

I imagined the GPS antenna would be under the bezel or chapter ring as with the 2 current style Astron GPS designs but its not. Perhaps the shock protection design requirements meant this approach was not suitable for a G-Shock?! 
Apparently the GPS antenna is within the square at the 6 o'clock position in the pic below. I wonder what the typical GPS capture/sync time will be with this type of antenna?
The RC antenna is at the 12 o'clock position.

(pic from the first link in my previous post above)
(The CXD5600GF is the GPS LSI chip)





chris01 said:


> Now, Casio, just put it in a decent case, please.


I imagine the various shock protection measures for a latest gen, higher end G-Shocks must add quite a few mm. It would be great if this module was fitted into something like an Oceanus. I wonder by how much that would shrink the dimensions?...Perhaps significantly?!! :think:


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## everose (Jan 15, 2010)

ronalddheld said:


> Decent case and display would be my request.


I am no hardcore G-Shock fanatic like many of the guys over at f17 but it seems to me that Casio believe analog G Shocks can command premiums over similarly functional digital models. I think this is partly why they have worked so hard over the past few years to develop technologies which bring higher levels of shock protection/ruggedness/durability to their analog displays.
So it did not really surprise me that their first RC/GPS piece was an all analog design but i had vain hope for a digital or perhaps an ana/digi.

With recent developments in digital display technologies going beyond regular LCD display types, i am surprised Casio has not been at the forefront of these new developments.
If they introduced a higher end digital display technology then we may have a better chance of higher end models such as this RC/GPS being digital.

I imagine we still have a few more years to wait until we see 'less premium' conventional GPS timekeeping watches starting to appear which will likely include vfm all digital versions.


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## Andrew McGregor (Dec 27, 2011)

Huh? There have been all-digital GPS watches for years... Suunto Ambit (now in version 2) and the Garmin Fenix family come to mind immediately. Yes, they're smartwatches, kind of, and need charging, and are extremely sport-focused, but they do exist and have for a long time. Those two GPS sync continuously as well.


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## ronalddheld (May 5, 2005)

Andrew McGregor said:


> Huh? There have been all-digital GPS watches for years... Suunto Ambit (now in version 2) and the Garmin Fenix family come to mind immediately. Yes, they're smartwatches, kind of, and need charging, and are extremely sport-focused, but they do exist and have for a long time. Those two GPS sync continuously as well.


I believe that the Implicit requirement was for a dress digital GPS watch.


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## everose (Jan 15, 2010)

ronalddheld said:


> I believe that the Implicit requirement was for a dress digital GPS watch.


Exactly, which is why i stated, _*"conventional GPS timekeeping watches."*_....which imho Suunto, Garmin et al are not.


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## Andrew McGregor (Dec 27, 2011)

Ah, missed that.

Although the Ambit 2 Sapphire comes close-ish.


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## ronalddheld (May 5, 2005)

Andrew McGregor said:


> Ah, missed that.
> 
> Although the Ambit 2 Sapphire comes close-ish.


Why that one, the sapphire crystal? I believe that people think dress and digital are incompatible.


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## chris01 (Jan 5, 2011)

ronalddheld said:


> Why that one, the sapphire crystal? I believe that people think dress and digital are incompatible.


While these obviously have attractions for specific activities, I think that a 50-hour (max) battery life is incompatible with being a useful wristwatch.


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## petew (Apr 6, 2006)

chris01 said:


> While these obviously have attractions for specific activities, I think that a 50-hour (max) battery life is incompatible with being a useful wristwatch.


The 50 hour battery life is only when the GPS is constantly on tracking an activity. In normal day to day usage, you could get a few weeks or more of battery life out of an Ambit.


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## ronalddheld (May 5, 2005)

petew said:


> The 50 hour battery life is only when the GPS is constantly on tracking an activity. In normal day to day usage, you could get a few weeks or more of battery life out of an Ambit.


That sounds more reasonable for battery life with a daily sync.


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## Andrew McGregor (Dec 27, 2011)

ronalddheld said:


> Why that one, the sapphire crystal? I believe that people think dress and digital are incompatible.


Well, it has a stainless case and generally looks more stylish.

This, I think, counts as a dress digital:


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## ronalddheld (May 5, 2005)

Andrew McGregor said:


> Well, it has a stainless case and generally looks more stylish.
> 
> This, I think, counts as a dress digital:
> View attachment 1449165


Yes, one of the few current examples.


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## everose (Jan 15, 2010)

Andrew McGregor said:


> This, I think, counts as a dress digital:
> View attachment 1449165


I love the clarity of EPD but unfortunately at the moment it cannot provide a screen scroll/refresh speed suitable for things like *continuously *counting secs, which for me, would be an important requirement for a GPS timekeeping watch.

Re Ambit2:-
I am not very familiar with these GPS Activity pieces but yesterday I read an Amazon review (Yes, I know they can potentially be quite unreliable!) which stated:- 
Ambit2, "Does not auto-correct the time based on GPS. (limited time correction)" 
I'm unsure how significant this is in daily wearing. Perhaps manual time syncing is a major hassle? :-s



petew said:


> The 50 hour battery life is only when the GPS is constantly on tracking an activity. In normal day to day usage, you could get a few weeks or more of battery life out of an Ambit.


The spec for Ambit2 states batt life with ABC is approx 30 days. Is that with or without any GPS (time) syncing? If its without then surely it defeats the purpose in respect of this forum.

One aspect of these GPS Activity pieces which i really admire is their ability to update/upgrade firmware.


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## Andrew McGregor (Dec 27, 2011)

The Pebble display is fast enough to show seconds (would be tricky to calibrate that though... ePaper refresh speeds are temperature dependant)... you don't notice the update time in practice, the UI is very responsive. In any case, a good LCD would be fine (also temperature dependant though). Only analog steppers, LED and OLED are not temperature dependant.

Ambit2 only does manual sync (but continuously while the GPS is logging) with current firmware. It's certainly possible for a firmware update to do a periodic sync.


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## everose (Jan 15, 2010)

Andrew McGregor said:


> The Pebble display is fast enough to show seconds...


Wow, that Pebble refresh/scroll is MUCH faster than the Seiko EPD's. 
My understanding is that EPD's use most energy to change the screen and very little energy once the screen is stationary. Perhaps this energy consumption characteristic is why the solar Seiko EPD's are much slower than the rechargeable Pebble EPD's.

Anyway for a 'conventional GPS digital watch' i would not want to be required to plug-in to recharge it every 2-4 weeks. 
My psyche is just not disciplined enough for such tasks! ;-)


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## ronalddheld (May 5, 2005)

It is a fact of modern life that you charge up your cellular phone daily(which you ahd to learn to do). Unless battery life improves by an order of magnitude smartwatches will have the same deficit.


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## Andrew McGregor (Dec 27, 2011)

ronalddheld said:


> It is a fact of modern life that you charge up your cellular phone daily(which you ahd to learn to do). Unless battery life improves by an order of magnitude smartwatches will have the same deficit.


Well, probably so. Still, the Pebble is a useful tool despite that... but I can't be bothered with it when I'm not on call.

It is entirely possible for the battery life to improve that much, the Pebble doesn't have or need a GPS, only its bluetooth radio. The most expensive power user is probably the vibrating alert motor, and I can't see a way to improve that.


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## ronalddheld (May 5, 2005)

If we are talking smartwatches, why not run Clocksync on Android phones(or the IOS equvalent) and sent the time to the smartwatch once or twice per day? No windows at night or being outside needed.


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## chris01 (Jan 5, 2011)

ronalddheld said:


> If we are talking smartwatches, why not run Clocksync on Android phones(or the IOS equvalent) and sent the time to the smartwatch once or twice per day? No windows at night or being outside needed.


Thanks very much, Ronald. Now we have a phone AND a watch to keep charged just to get the time!


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## ronalddheld (May 5, 2005)

chris01 said:


> Thanks very much, Ronald. Now we have a phone AND a watch to keep charged just to get the time!


If the watch has WiFi you can sideload Clocksync connect and sync the time. Still have to charge both.


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## watchcrank_tx (Sep 1, 2012)

The pursuit by the large manufacturers of radio- and GPS-synced watches has puzzled me for some time, given that most of the target audience of such gadgets will already own a smartphone with GPS on-board. It seems to me that syncing the smartphone's clock to GPS and then syncing a watch to the smartphone over Bluetooth would be the simpler, lower-cost, lower-power-consumption path as far as the watch itself is concerned.


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## chris01 (Jan 5, 2011)

watchcrank said:


> The pursuit by the large manufacturers of radio- and GPS-synced watches has puzzled me for some time, given that most of the target audience of such gadgets will already own a smartphone with GPS on-board. It seems to me that syncing the smartphone's clock to GPS and then syncing a watch to the smartphone over Bluetooth would be the simpler, lower-cost, lower-power-consumption path as far as the watch itself is concerned.


But what happened to the autonomous accuracy that is the 'holy grail' of HAQ? The good old RC that is only just about tolerated on this forum does a similar job with far less cost and complexity, in a single package that can run for years with nothing more than the occasional sunny day.  Many people with smartphones seem to have abandoned wristwatches as 'so last century', missing the point that telling the time used to require no more than a reflexive glance at the wrist.

I say that we must insist on a rapid evolution of GPS and/or CSAC so that we can have a simple, wearable HAQ that offers a genuine all-round improvement over our TCs.


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## gaijin (Oct 29, 2007)

watchcrank said:


> The pursuit by the large manufacturers of radio- and GPS-synced watches has puzzled me for some time, given that most of the target audience of such gadgets will already own a smartphone with GPS on-board. It seems to me that syncing the smartphone's clock to GPS and then syncing a watch to the smartphone over Bluetooth would be the simpler, lower-cost, lower-power-consumption path as far as the watch itself is concerned.


You are assuming the time displayed on your cell phone is accurate - it is not.

Here are some data I logged comparing the time on my iPhone 4 to a known good time reference (Time in Koninkrijk der Nederlanden now - Time.is ):










As you can see, the iPhone time can be off by as much as -2.59 seconds in this population.

HTH


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## ronalddheld (May 5, 2005)

My clouded crystal ball sees the future HAQ as CSAC/GPS or MEMS/GPS. I believe that the future for most people will be wireless network based time no matter how far off from GPS it is.


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## Hans Moleman (Sep 24, 2007)

watchcrank said:


> The pursuit by the large manufacturers of radio- and GPS-synced watches has puzzled me for some time, given that most of the target audience of such gadgets will already own a smartphone with GPS on-board. It seems to me that syncing the smartphone's clock to GPS and then syncing a watch to the smartphone over Bluetooth would be the simpler, lower-cost, lower-power-consumption path as far as the watch itself is concerned.


A GPS device knows the exact time to within nanoseconds. That time is a by-product when it determines its position.

That time however is not used anywhere else.

Exceptions are GPS clocks. They are ordinary GPS devices with special provisions that export this time to the outside world.


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## chris01 (Jan 5, 2011)

Hans Moleman said:


> A GPS device knows the exact time to within nanoseconds. That time is a by-product when it determines its position.
> 
> That time however is not used anywhere else.
> 
> Exceptions are GPS clocks. They are ordinary GPS devices with special provisions that export this time to the outside world.


If you don't need to carry it on your wrist, GPS is an excellent time source, being easy and cheap to set up, and providing accessible NTP to any client device. With one or more networked GPS clocks your home/office/etc. can be autonomously accurate, without even any need for an external internet connection. I guess that CSAC could now do a similar job, but at far greater cost. However, until one of these technologies fits a normal watch I can see absolutely no reason to abandon TC and RC.


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## ronalddheld (May 5, 2005)

I have read of a CSAC GPSDO but cannot site that reference.


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## Hans Moleman (Sep 24, 2007)

chris01 said:


> If you don't need to carry it on your wrist, GPS is an excellent time source, being easy and cheap to set up, and providing accessible NTP to any client device. With one or more networked GPS clocks your home/office/etc. can be autonomously accurate, without even any need for an external internet connection. I guess that CSAC could now do a similar job, but at far greater cost. However, until one of these technologies fits a normal watch I can see absolutely no reason to abandon TC and RC.


A GPS clock doesn't have the hassle of getting it synched. It is synched to the GPS' atomic clocks inside the satellites all the time.

Your own atomic clock is great, until you realize you need to set it to the correct time somehow. Or at least verify it still has the correct time.
How do you verify your own atomic clock to a nanosecond or so? With great difficulty.


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## chris01 (Jan 5, 2011)

Hans Moleman said:


> A GPS clock doesn't have the hassle of getting it synched. It is synched to the GPS' atomic clocks inside the satellites all the time.
> 
> Your own atomic clock is great, until you realize you need to set it to the correct time somehow. Or at least verify it still has the correct time.
> How do you verify your own atomic clock to a nanosecond or so? With great difficulty.


This will be a bit of a problem for CSAC watches, won't it? If you're going to need on-board GPS to set the time, then why do you need CSAC? Ignoring the geek factor, of course. Internet NTP is nowhere near good enough.


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## ronalddheld (May 5, 2005)

Hans Moleman said:


> A GPS clock doesn't have the hassle of getting it synched. It is synched to the GPS' atomic clocks inside the satellites all the time.
> 
> Your own atomic clock is great, until you realize you need to set it to the correct time somehow. Or at least verify it still has the correct time.
> How do you verify your own atomic clock to a nanosecond or so? With great difficulty.


Down to a nsec that is too hard to easily accomplish. I would settle for several nsec for initializing my CSAC watch.


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## Hans Moleman (Sep 24, 2007)

ronalddheld said:


> Down to a nsec that is too hard to easily accomplish. I would settle for several nsec for initializing my CSAC watch.


I can understand that.
I believe they almost all are synched to GPS clocks. It's just too convenient.

That drags them down a bit though.


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## ronalddheld (May 5, 2005)

Hans Moleman said:


> I can understand that.
> I believe they almost all are synched to GPS clocks. It's just too convenient.
> 
> That drags them down a bit though.


The other choices I can think off, are to initialize from a GPSDO or some primary frequency standard part of the ensemble of clocks defining TAI.


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## Andrew McGregor (Dec 27, 2011)

gaijin said:


> You are assuming the time displayed on your cell phone is accurate - it is not.
> 
> Here are some data I logged comparing the time on my iPhone 4 to a known good time reference (Time in Koninkrijk der Nederlanden now - Time.is ):
> 
> ...


Having read the code for the Time.is web client, I would strongly suggest that it is time.is that's off by 2.59s and your iPhone is bang on. Time.is does no correction for network latency, and if you have a bufferbloated modem or ISP head end, your excess latency could be a couple of seconds.

Nobody in the HAQ forum should treat time.is as reliable, it isn't.


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## Andrew McGregor (Dec 27, 2011)

chris01 said:


> This will be a bit of a problem for CSAC watches, won't it? If you're going to need on-board GPS to set the time, then why do you need CSAC? Ignoring the geek factor, of course. Internet NTP is nowhere near good enough.


Sure it is, if you're prepared to wait a week or two for it to settle down to optimal sync. NTP can be nanosecond accurate, if you choose your peers well, it just takes a really long time to get good measurements because it is fighting packet queueing noise.


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## Hans Moleman (Sep 24, 2007)

Andrew McGregor said:


> Sure it is, if you're prepared to wait a week or two for it to settle down to optimal sync. NTP can be nanosecond accurate, if you choose your peers well, it just takes a really long time to get good measurements because it is fighting packet queueing noise.


I noticed that NTP does very well on a Sunday morning. 
Nice and early when no-one else is putting demands upon the network. The response times must be very predictable then.

NTP must be doing very well overnight then for the same reasons. I have never tried though.


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## Hans Moleman (Sep 24, 2007)

Andrew McGregor said:


> Nobody in the HAQ forum should treat time.is as reliable, it isn't.


From where I am sitting, time.is isn't that bad.
I see a 30-50 ms difference between their time and my GPS time.


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## watchcrank_tx (Sep 1, 2012)

chris01 said:


> But what happened to the autonomous accuracy that is the 'holy grail' of HAQ?


Nothing, I hope.  I was speaking simply about the simple radio- and GPS-corrected watches with low-accuracy movements.



gaijin said:


> You are assuming the time displayed on your cell phone is accurate - it is not.
> As you can see, the iPhone time can be off by as much as -2.59 seconds in this population.
> 
> HTH


No, I am not making that assumption, since I'm well aware that most phones do not sync often, some sync to local networks and not to GPS even when good signal is available, GPS APIs (at least in Android) are obscure and opaque, most phone OSes prioritize other routines to drawing the screen, etc. These do not however appear to be complete technical barriers.



Hans Moleman said:


> A GPS device knows the exact time to within nanoseconds. That time is a by-product when it determines its position.
> 
> That time however is not used anywhere else.
> 
> Exceptions are GPS clocks. They are ordinary GPS devices with special provisions that export this time to the outside world.


.

GPS-enabled smartphones have the ability to get the time out of their GPS chips, but the APIs can be difficult and sometimes buggy. Still, it seems like a much smaller effort to me to perfect these processes in good software and then to make a small bluetooth watch to work with a phone running that app than it is to reduce the power usage of the GPS watches to the point they can be made reasonably small.


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## gaijin (Oct 29, 2007)

Andrew McGregor said:


> Having read the code for the Time.is web client, I would strongly suggest that it is time.is that's off by 2.59s and your iPhone is bang on. Time.is does no correction for network latency, and if you have a bufferbloated modem or ISP head end, your excess latency could be a couple of seconds.
> 
> Nobody in the HAQ forum should treat time.is as reliable, it isn't.


Then how do you explain that GPS time is always the same as the Time.is time?










I confirm this correlation almost every day and have done for the last couple of years.

Your conclusion about the reliability of Time.is is, in my humble opinion, wrong.

HTH

Edit to add:

Here's another shot I just took showing a GPS watch and the Time.is web site - funny, still in perfect sync:










When two time references consistently agree, does not one validate the other?

Further edit to add:

How about another reference that agrees with Time.is? Here's a quick and dirty pic of an "Atomic" clock I use which syncs with the WWVB radio time signal:










Again, in perfect agreement with the Time.is web site.

Based on these observations, I maintain that the Time.is web site is a reliable time reference.


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## Andrew McGregor (Dec 27, 2011)

It seems to be reliable on your network, at the time you took those pictures. Which is certainly possible.

It isn't on mine, it reliably tells me that I'm 300ms off, when my local NTP server is usually GPS synced and the whole thing is nailed down to within a few ms. As it happens, my ping time to time.is is around 300ms:
PING time.is (204.62.12.153): 56 data bytes
64 bytes from 204.62.12.153: icmp_seq=0 ttl=46 time=304.668 ms

And I'm not making up the 'no network latency correction' bit, the code is so short and obvious that it couldn't possibly hide... do a 'view source' on the website and read it for yourself.

NTP on the other hand does do latency correction (the 'delay' column):
ntpdc> peers
remote local st poll reach delay offset disp
=======================================================================
*time6.apple.com 192.168.1.109 2 512 1 0.17529 0.007010 0.43311

Shows that I'm about 7ms off time6.apple.com, which is 175.3ms away from me, and it will be slowly steering the two together (my GPS is offline right now, as I just moved house and haven't put that system back together again).


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## Andrew McGregor (Dec 27, 2011)

Hans Moleman said:


> From where I am sitting, time.is isn't that bad.
> I see a 30-50 ms difference between their time and my GPS time.


If you ping time.is, I predict you'll see something around 30-50ms.


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## ronalddheld (May 5, 2005)

None of this recent discussion gives me confidence that i would be using mentioned sites to synchronize any CSAC. Maybe a TCXO watch if possible.


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## Andrew McGregor (Dec 27, 2011)

I've said before... you can't use a *web site* to synchronise anything. That doesn't mean you can't use a *computer*, just that you have to be much more careful. NTP or IEE 1584 PTP is capable of the job, if used carefully.


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## Hans Moleman (Sep 24, 2007)

Andrew McGregor said:


> If you ping time.is, I predict you'll see something around 30-50ms.


It is 200 ms.


> 64 bytes from 204.62.12.153: icmp_seq=3 ttl=49 time=208 ms
> 64 bytes from 204.62.12.153: icmp_seq=4 ttl=49 time=207 ms
> 64 bytes from 204.62.12.153: icmp_seq=5 ttl=49 time=218 ms
> 64 bytes from 204.62.12.153: icmp_seq=6 ttl=49 time=207 ms


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## Andrew McGregor (Dec 27, 2011)

Hans Moleman said:


> It is 200 ms.


Ohhkay, there's something fishy going on there... I suppose time.is might do some kind of latency compensation server-side. But in any case, I don't see how one could trust a browser and that whole messy web stack to do precise timing.


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## Hans Moleman (Sep 24, 2007)

Andrew McGregor said:


> Ohhkay, there's something fishy going on there... I suppose time.is might do some kind of latency compensation server-side. But in any case, I don't see how one could trust a browser and that whole messy web stack to do precise timing.


I think so too. There is more going on that just HTML and Javascript.

I don't think a web page timer will be out more than one second. Up to 100 ms seems a safe bet. Just noticeable.
Nowhere near the 10 ms that NTP can achieve. NTP needs time to do its thing though.


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## dicioccio (Jul 14, 2011)

I've checked my Casio RC watch with time.is and it is aligned. I can see a very small difference, compatible with the 200ms latency read by Hans Moleman ping-ing the site. To me, it appears a very good approximation and it doesn't annoy me. On the contrary, thanks a lot for giving me the opportunity to know this wonderful time reference site !


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## Andrew McGregor (Dec 27, 2011)

dicioccio said:


> I've checked my Casio RC watch with time.is and it is aligned. I can see a very small difference, compatible with the 200ms latency read by Hans Moleman ping-ing the site. To me, it appears a very good approximation and it doesn't annoy me. On the contrary, thanks a lot for giving me the opportunity to know this wonderful time reference site !


Your ping will be different, it depends on where you are in the network.

200ms is not very small when it comes to computer timing... 200µs is small-ish, 200ns is actually small.

If you have a Mac, open your system preferences, go to 'date & time', make sure 'set date and time automatically' is checked, and if you have been online for a few minutes with the setting checked the clock in that control panel will be much better synced than time.is. If you're on Linux, make sure ntpd is installed and running, and run an xclock. For Windows, no idea, I haven't used Windows for a decade and don't plan on starting.


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## ronalddheld (May 5, 2005)

If you are on Windows run Catalin's n.cmd file.


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## rcs914 (Apr 30, 2007)

I can't imagine any sync for a CSAC which isn't a GPS. If you are going to spend the money to have your own atomic clock wristwatch, why would you not want it synched with the most accurate of external signal sources to set up the count?


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## 325xia (Apr 7, 2014)

Can't wait.


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