GPS Position Accuracy

I enabled those modules - guessing that I may want to use them in the future....  there is currently no ANT+ code in there, at the moment updates are approved instantly, the initial upload was a couple days. It wasn't a case of me being lazy,  quite simply I have no programming background what so ever, and enabling stuff I guessed the programmer might use was the quickest way for me to make something to use.      So Jim - is it possible to use bluetooth for playing sounds in earbuds?  

Nick said:

So Jim - is it possible to use bluetooth for playing sounds in earbuds?  

Probably not the way you are thinking.  In a CIQ app it will play the normal audio prompts on watches that allow that.  So if in setting>audio prompts you have lap alerts turned on, and in your app, there's a lap added, you'll hear the prompt..

Attention.playTone() is the same way if Audio Tones is on in settings.  You'll hear beeps, etc, if your app sounds a beep.

You don't need the BLE permission for these.

The main challenge that I have faced over the past 10 years in the development of my sailboat racing app has been coming to terms with the limitations of the platform, the operating environment and the user base.

I think you have neglected to accept that a) some of the limitations require serious software engineering to work, b) some of the features rely on a far more tech-savvy user base than actually exists and c) some of the limitations actually preclude the delivery of otherwise very attractive features.

As examples, I offer the following selection: 

In category a (platform limitations), the wind speed and direction selection feature is unworkable while in motion as the un-damped display makes it impossible to select a speed within 5 kts or direction within 10°.

In category b (user capability), from my experience there is very little chance of your user being willing or able to create the log file to capture the polars, or of being able to use the picker to create a waypoint.

In category c (undeliverable features), the effective generation of VMG and Polars, whilst highly desirable and theoretically feasible is quite impractical since it is highly unlikely for the TWS/TWD to remain constant for any useful period of time or an accurate value to result, since they rely on an accuracy of around 2-3 Kts and 5° resp. 

Sorry to be so negative, but you did invite a review.

Thanks, I'd say it's a fairly positive review.....I developed that in 2 months, it is the only sailing app I am aware of that has the ability to capture polar data that I could find and so I don't believe nothing is better than something in this case .

I already had some feedback about the auto wind speed and direction - yeah there is no way to get around setting the wind direction if you are moving and creating apparent wind, which is why the setting is at startup. Since Speed is not used in any calculations, I decided that 5 kts is close enough, as the majority of users are guessing the wind speed and direction anyhow - which changes constantly.

??? I suggest you try the feature, and then read the feature blurb..... it does exactly what it says it does in the blurb.....Exactly

No need for slanderous remarks..... 

I can't speak from inside Garmin, but from the point of view of a customer looking for accuracy, there's only so much accuracy you can get.  Well-designed GPS receivers are capable of achieving horizontal accuracy of 3 meters or better and vertical accuracy of 5 meters or better 95% of the time, according to the GPS Standard Positioning Service Performance Standard published every year or so for the last several years (I haven't checked the current data), this and other info at GPS.gov.  

It's unfortunate that GPS is not (yet) millimeters of accuracy but meters, and subject to some unique confounding variables, such as someone's arm blocking signals, or trees (which both may be less a problem nowadays).  There's almost always some level of distortion at work when you're moving through the forest, but certainly less to worry about if you're out on the water sailing.  Still not perfect, though, would be a safe bet, but pretty good overall.  

I'm surprised and very skeptical whenever I start an activity and the watch immediately beeps indicating it has perfect satellite signal.  I would suspect that this immediacy is also a marketing ploy, since if I had to compare Garmin watches with an iWatch I would probably say the iWatch is more "smart"... but as far as I'm concerned Garmin was doing GPS before iWatches existed so, I'm on Garmin's side.  sorry to bump this topic, the question just got me thinking.

An app I'm working on, which will be really cool by the way, also depends in large part, on the accuracy level of GPS.  And, it's something which I'm just learning to embrace, this imperfection.  I'm just widening the margin for error, and the program still works perfectly in different conditions.  In the writeup for my app, it will mention that the GPS is not perfect.  It's not Garmin's imperfection either, it's just the technology of GPS itself.  ok enough soapbox.. also apologize for not answering the specific question of the OP

The  concern was not with how large the accuracy error is.... the requests I had were only asking what the accuracy was, and I was unable to tell them. I did figure out and contact the GPS chip manufacturer who I am positive would know the answers to both of my questions - however they are bound to confidentiality with Garmin.

I asked them - does the chip use GPS signal doppler shift to calculate velocity. Even with only that info I could make a guess at the size of the speed error since doppler shift is incredibly accurate for speed calculations - much more so than a positional error, and is the positional error passed ( of course it is ) as a quantity.

Other than that as we know - Garmin have some kind of filter on the GPS accuracy reporting which tells you good/bad/other and not any values, also does not tell you what the speed errors are, ( or doppler shift errors if it uses doppler measurement )

So the guys can't use the info in any of their speed reading competitions because they cannot quantify the accuracy of the signal, and that is a prerequisite.

Nick