How Much Accuracy is Enough?

Thread: How Much Accuracy is Enough?

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  1. #1
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    How Much Accuracy is Enough?

    Good morning all! This is my first post, but I am a long time observer of this forum and a long time Casio watch 'accumulator'; I don't really think you could call what I have a collection since until very recently it has been unfocused. I operated following the 'break a watch, buy a watch' method of accumulation .

    I work in an industry that is ruled by time (GPS-based surveying and precise positioning at a very large commercial airport). As a matter of course I try to wear accurate time pieces at work, and I've found that Casios fit that bill nicely.

    Recently I picked up a few Casios that do the atomic time signal synchronization - a GS-1100, a GW-503, a very underrated non-G Shock WV-200 and just yesterday a Riseman GW-9200. I think time signal synchronization is a very neat trick. Casio has done a great job integrating the technology into their products.

    Howerver, atomic time signals broadcast via radio are quite limiting. From a global perspective the signals are very restricted in coverage (particularly in local daytime). What happens if you are in South America, or Africa, or the vast regions of China, Russia and Eastern Europe that are not covered by broadcast time signals?

    So here's my question - why not GPS?

    I am well aware of the issues related to integrating GPS into consumer devices like smart phones. GPS receivers are getting smaller and smaller with each generation (the GPS receiver in the iPhone is less than 4mm x 4mm in size). Antennas are often the limiting factor; it is very difficult to make an efficient GPS antenna that fits into a small space. However, these antenna challenges are directly related to the need to track three or more satellite signals to determine position. If all we are after is the highly accurate and precise time signal from the atomic clocks carried aboard each GPS satellite then all we need to do is track and synchronize with one satellite signal. This greatly simplifies the receiver and antenna requirements.

    Since there are always GPS satellites overhead this would eliminate the coverage and time-of-day issues related to synchronizing with the broadcast signals. This makes the concept of the 'atomic' watch truly world-wide and 24/7.

    Are there any indicators from Casio or other watch manufacturers that they are investigating this technology, or has it been looked into and it's just not feasible?

    Thanks, and it's good to be aboard!

    Brian

  2. #2
    Member AirWatch's Avatar
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    Re: How Much Accuracy is Enough?

    I think you're looking too far ahead into the future as far as Casios having GPS. My hunch is they're gonna milk this Multi Band deal for all it's worth first, unless an unexpected competitor jumps in the market with GPS wristwatches which would be the state-of-the-art accuracy on the wrist as we know it.

    Oh, I almost forgot! Welcome to the forums! Strong first post, too!
    Last edited by AirWatch; September 11th, 2010 at 17:56.

  3. #3
    Member cal..45's Avatar
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    Re: How Much Accuracy is Enough?

    Quote Originally Posted by bharen View Post

    So here's my question - why not GPS?
    simple answer for two reasons:

    1. it doesn't work inside buildings. it is already ridiculous, that people strap off their watches at night, just to find an optimal place to put them for RC. it would become totally absurd if they had to put the watches outside, which is often simply not possible, and certainly even more often not welcome.

    2. power. even if GPS would be working under all conditions, casio had to step away from their "tough solar" technique. GPS is a power sucking thing and low capacity solar batteries are anything but helpful in that matter. "tough solar" is a big selling, marketing cart horse for casio and they will not drop it for the sake of some other technique, which has as much limitations as the six radio transmitters currently.


    cheers
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  5. #4
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    Re: How Much Accuracy is Enough?

    Quote Originally Posted by cal..45 View Post
    simple answer for two reasons:

    1. it doesn't work inside buildings. it is already ridiculous, that people strap off their watches at night, just to find an optimal place to put them for RC. it would become totally absurd if they had to put the watches outside, which is often simply not possible, and certainly even more often not welcome.
    I think the fact that the wearer can sync anytime he/she is outdoors or near a window would mitigate this issue. Remember, GPS is 24/7 worldwide.

    2. power. even if GPS would be working under all conditions, casio had to step away from their "tough solar" technique. GPS is a power sucking thing and low capacity solar batteries are anything but helpful in that matter. "tough solar" is a big selling, marketing cart horse for casio and they will not drop it for the sake of some other technique, which has as much limitations as the six radio transmitters currently.
    Power is an issue with GPS, but most of the power requirements in a GPS receiver actually stem from the display, the need to drive additional board devices and the fact that the receiver needs to be on and working in a continuous mode to provide a location fix. If a watch-integrated GPS receiver were only used to track a single satellite signal until synchronization occurred then power down until the next synchronization command was received, I think power requirements could be kept quite low.

    Thanks for the comments!

    Brian

  6. #5
    Member cal..45's Avatar
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    Re: How Much Accuracy is Enough?

    Quote Originally Posted by bharen View Post
    I think the fact that the wearer can sync anytime he/she is outdoors or near a window would mitigate this issue. Remember, GPS is 24/7 worldwide.
    near a window is not good enough . it might work with the much more powerful antenna of a garmin handheld device but not with such a small antenna of a watch (it doesn't work with my garmin forunner 205 GPS watch either). of course GPS is 24/7 worldwide, so is the transmitting of the six radio towers (24/7, not worldwide of course).....

    Power is an issue with GPS, but most of the power requirements in a GPS receiver actually stem from the display, the need to drive additional board devices and the fact that the receiver needs to be on and working in a continuous mode to provide a location fix. If a watch-integrated GPS receiver were only used to track a single satellite signal until synchronization occurred then power down until the next synchronization command was received, I think power requirements could be kept quite low.

    Thanks for the comments!

    Brian

    ....but it is the software that tells the watch when to sync, and since the watch doesn't know when the wearer is inside or outside it would have to do it on a hourly basis - at least. and THAT would require an awful lot of power (at least as long as one sync per day was succesful and you know it can take several minutes to lock on successfully to a GPS signal, even under optimal circumstances, not to mention when one is on the move)



    cheers
    Last edited by cal..45; September 11th, 2010 at 19:10.
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  7. #6
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    Re: How Much Accuracy is Enough?

    I'm not up to speed with the tech' side of things but surely putting GPS into a watch and solving the power demands can't be too much of a big deal?

    I would also have thought that Casio who do make a very big deal of technology would have some sort of fix on it - albeit maybe a way down track.

    Personally I love the tech' that goes into these watches.

    In terms of how accurate you really need? Well for me I like the accuracy of waveceptor + the unbelievable accuracy of my 7710 but I guess in real life it wouldn't matter if my watches were a few minutes out each way. I don't have a need for super accuracy in my life.
    Current watches:

    Casio GW-2000B
    Casio G-7710
    Rolex Explorer

  8. #7
    Member dkpw's Avatar
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    Re: How Much Accuracy is Enough?

    Can I point you at this FAQ.

    Atomic will do most of us just fine.
    David
    Ω Speedmaster, Explorer 214270, Sub 16610, Seiko Shogun, Pepsi Turtle, PRS-29B
    Steinhart OVM, Citizens: Ray Mears 2 BN0151-09L & BN2017-02E,
    & far too many G-Shocks



  9. #8
    Member l_cypher's Avatar
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    Re: How Much Accuracy is Enough?

    By the way:

    The time signale transmitted by GPS is always the UTC.
    Time zones or DST will not be considered. So the watch has to do all calculating work. An automatic change to DST and back is not possible.
    My watches:
    Sinn 104 St Sa A | Casio CBX-1000 | Casio WV-M120 | Junghans Mega1 | Junghans Olympic

  10. #9
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    Re: How Much Accuracy is Enough?

    Quote Originally Posted by cal..45 View Post
    simple answer for two reasons:

    it is already ridiculous, that people strap off their watches at night, just to find an optimal place to put them for RC. it would become totally absurd if they had to put the watches outside, which is often simply not possible, and certainly even more often not welcome.

    cheers
    Man,what is your problem against waveceptor technologie?
    When i go to sleep i strapp off my watch so what is the diference putting in the nearest window? come on,its a great technology
    - Casio Protrek PRW-1500-1VER -

  11. #10
    Member GregNYC's Avatar
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    Re: How Much Accuracy is Enough?

    I have a Garmin 310XT GPS running watch which works very easily and well. What I like it for is that it tells me my distances covered. I like it very much! But it only catches the signal outside. Otherwise, in my life, the horological accuracy of a mechanical automatic watch is fine for me.

    With my Atomic G-Shocks and Protreks, where I live and with the angle of the windows, I almost never catch a signal. So I end up re-setting them manually every few months.

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    (wrist shot)

    Last edited by GregNYC; September 12th, 2010 at 05:13.

    --Greg

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