Just to make it clear before I start I'm not a scientist, I'm not a doctor, I'm just an old beach bum. Now that's out of the way I'm certainly not going to tell you I'm smarter than you and you should listen to me. On the contrary take whatever I show you here as a guideline not a rule.
As I'm a simple man I like simple things and it's the same with a gps. I just want it to record raw data with doppler speed errors and talk to me....I get lonely on the water! I'm not interested in connecting cables, analysing noise, standing still and looking pretty. I want something that tells me how fast I'm going when I'm actually moving while I still can.
So I came up with the simple man's gps SIMANGPS or ROOGPS for my own version! No it's not April 1st, this is serious stuff and I'm not joking. Stop giggling over in the back corner Daffy.
What I'm going to show you is earth shattering and will forever change the speed time continuum when powered by a flux capacitor.......well not really as flux capacitors aren't available commercially yet other than at the Area 51 gift shop. Sorry I digress.
The latest generation of Android 10 phones tend to be sold with the capability to use 3 or 4 gps systems to give you a location. The cheapy $60 version I've been experimenting with has GPS, Glonass, Beidou and Galileo. What it also has is S.Acc errors, i.e. the speed accuracy of the doppler speed. Just what I've been looking for. It case this is major news to you it just shows you haven't been reading my previous posts (I told you about this in May 2020). For a bit more money you can get a fully waterproof phone so you won't need an aquapac to keep it dry. There are also dual frequency GPS phones on the market that are even more accurate.
You can use a neat little free app called GPSTest to view the data and record it if you want. Shows all the sats being used and the accuracy. play.google.com/store/apps/details?id=com.android.gpstest&hl=en_US&gl=US
For those of you with inquiring minds this probably isn't enough, you want to have all the GPS cake and analyse it too. So what you need is an app to record the raw data and download it. Sadly there isn't one however that's not the end of the story. Google in its great wisdom is happy to give you gratis a copy of Android Studio. So what you may ask! Well smartypants I'll let you in on a secret...it lets you write your own apps so you can record the data you want and do with it whatever you wish. developer.android.com/studio
I've been doing just that....aren't I a smart little bunny? Well not really as Studio makes it simple to do do. So I did. I have my own app to record the raw data and accuracy and automatically send it to me from the phone so I can analyse the file. Just working on it to tell me my speed while I'm moving. I've built my app to work with my phone and you can do the same if your heart so desires.
I reckon pretty much anyone can build the own SIMANGPS system using a cheap phone and their own app. It will never be officially recognised by any United Nations approved speed measuring secret society but it will keep you amused for hours. No need to post any pretty red and blue graphs to show how clever you are, just build your own and the speed will come.
Yours in Speed, Roo
Select to expand quoteRoo said..
There are also dual frequency GPS phones on the market that are even more accurate.
Don't go spending more money to specifically upgrade to a multi-frequency device, it's not interesting for our use-case.
Select to expand quoteJulienLe said..Roo said..
There are also dual frequency GPS phones on the market that are even more accurate.
Don't go spending more money to specifically upgrade to a multi-frequency device, it's not interesting for our use-case.
It's just to offer people options Julien if they have lots of money and are technerds! The simple $60 Android 10 phone does the job nicely.
If Roo can write a program on Android studio, I guess that pretty much proves that anyone can do so. So Roo says.
One might ask why you'd want to do that, since apps like WindsportTracker only require a download to record your speed, and even talk to you on the water if that's your thing. For some, just having a logo with their name might be worth the effort. For others, it might be the speed accuracy that Roo mentions, which was added with the release of Android 8.0.0.
So if you're interested in speed accuracy and write your own Android app, there's a couple of "gotchas" to look out for. One is that you might not get a reading on speed accuracy on your phone at all. But a quick look at the Android developer documentation shows that there's a method "hasSpeedAccuracy" that will tell you that. Some GPS chips that were widely used a couple of years back did not estimate speed accuracy, but maybe that has changed now.
The perhaps bigger one is the actual accuracy, and Roo was nice enough to provide an example. In his screen shot, the GPS uses 32 satellites (that's a lot) and reports nice CNO levels. But the speed accuracy is +- 1.1 m/s, or 2.1 knots. That's about 10-fold worse that what you get with a Motion. It's actually worse than a GT-31. Now that's just one number, and maybe others are better. But phones usually have very small GPS antennas which severely limits accuracy. When you're driving, a knot or two error in the speed matters little. In the GPS Team Challenge, such errors would mix up the ranking quite a bit.
But it's nice of Roo to point out another way to look at speed accuracy!
Select to expand quoteboardsurfr said..One might ask why you'd want to do that, since apps like WindsportTracker only require a download to record your speed, and even talk to you on the water if that's your thing. .........
I would think a 'Scientist' might ask the obvious question: "Does WindsportTracker record the error data?" 
Of course, it might be able to de done with GPS-Logit as well, but that would have to be added in to the functionality by Manfred. 
Select to expand quoteJulienLe said..
Don't go spending more money to specifically upgrade to a multi-frequency device, it's not interesting for our use-case.
Good point. As I understand it, (not being a Scientist and all 
) multi-frequency is a technology to enhance positional precision and may not help Doppler precision at all, but positional improvement could help with Alpha proximity circle accuracy.
Select to expand quotesailquik said..JulienLe said..
Don't go spending more money to specifically upgrade to a multi-frequency device, it's not interesting for our use-case.
Good point. As I understand it, (not being a Scientist and all ) multi-frequency is a technology to enhance positional precision and may not help Doppler precision at all, but positional improvement could help with Alpha proximity circle accuracy.
I am still waiting for good accuracy dual or more GPS system.For my rural fencing requirements. Professional survey service in this rural setting may cost thousands of dollars to mark your property borders.I believe that properly designed system using existing GPS satellites could offer few cm accuracy.Remember that we may have unlimited time, not in hurry when marking position. Our device and software could spend as much time as needed to scroll over satellites, apply correction etc.
I we look at any smart phone description or promotion, hardly anybody mention gps positioning accuracy.But in near future we could possibly measure our board length or our height using gps without any other tools.
It will be interesting to know what is theoreticall upper accuracy for device that could combine reading of all satellites. In the nearest future even low flying SpaceX Starlink satellites may serve as super accurate source, if only equipped with right software.\
Select to expand quote[Macroscien said..
I am still waiting for good accuracy dual or more GPS system.For my rural fencing requirements. Professional survey service in this rural setting may cost thousands of dollars to mark your property borders.I believe that properly designed system using existing GPS satellites could offer few cm accuracy.Remember that we may have unlimited time, not in hurry when marking position. Our device and software could spend as much time as needed to scroll over satellites, apply correction etc.
I we look at any smart phone description or promotion, hardly anybody mention gps positioning accuracy.But in near future we could possibly measure our board length or our height using gps without any other tools.
It will be interesting to know what is theoreticall upper accuracy for device that could combine reading of all satellites. In the nearest future even low flying SpaceX Starlink satellites may serve as super accurate source, if only equipped with right software.\
It is already here Macro and it is called RTK. It has cm positioning resolution. 
RTK off the shelf GNSS devices are rapidly reducing in price. Only a couple of years ago, they were in the order of a few thousand dollars and decreasing. The basic parts to make one yourself (if you have the skills, which I don't ) are a few hundred dollars.
But RTK solutions rely on a base station for differential correctional data. That can be an existing commercial one (AFAIK, too expensive in Australia for non commercial operations) or a second RTK device, and some sort of radio connection between the two (so you normally need to have 2 devices).
There is also a technology called PPP - Precise Point Positioning, which uses dual frequency receivers. This can also give you cm accuracy without the need for a base station, but I think those systems may still be more expensive. Not sure as I have not really investigated that tech recently. Both RTK and PPP usually require a much larger and more sensitive/sophisticated antenna than what we normally use.
It has been touted for some years now that RTK cm precision will eventually make it into Smart Phones, and experimental success has been demonstrated, but I think it is still some way off for production devices.
The satellites are not really the current limitation on accuracy as I understand it. It is the hardware and software, and how much you are prepared, and can afford, to spend. Sub cm GNSS accurate devices are used by Surveyers and Farmers every day now. (just to name two main groups).
Interestingly, I have been reading some papers that claim mm Doppler velocity accuracy can also be obtained from GNSS systems.
More to follow as soon as I have had a surf and done some math.
These require space and power. Which surveyors and farmers have plenty off but smartphones don't.
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled."
Select to expand quoteJulienLe said..
These require space and power. Which surveyors and farmers have plenty off but smartphones don't.
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled."
I hope that one day smartphones come with dual or triple system and we can get off the shelves ready survey tool.
Select to expand quoteJulienLe said..
These require space and power. Which surveyors and farmers have plenty off but smartphones don't.
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled."
I hope that one day smartphones come with dual or triple system and we can get off the shelves ready survey tool.
Select to expand quoteJulienLe said..
These require space and power. Which surveyors and farmers have plenty off but smartphones don't.
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled."
Very true. And what's another $5000 - $10,000, and $1000+ per annum. base station subscription when you are paying upwards of $200,000 for the tractor or harvester anyhow?
One of the smartphone RTK experiments I read about used the processing power of a smartphone, but it still needed an external higher grade antenna to make it work OK'ish. I can't find the link to that paper just now, but I think it was in GPS-World Magazine.
Here is a video, to cure your insomnia, about trying to use the low quality antenna from a typical smartphone in 2014. Technology marches on, and they might get there eventually, but it probably won't be in the next year to so...... 
:
Interestingly, he mentions at minute 13 that a slightly moving device has an easier time finding its footing compared to a stationary device.
Select to expand quotesailquik said..
I would think a 'Scientist' might ask the obvious question: "Does WindsportTracker record the error data?"
The only time that "error data" are every relevant is in the GPSTC challenge. You, who seems to be the person who has the final say about device approval, have made it clear that there is no chance that only devices with error data can be approved.
So as a GPSTC member, I ask:
1. Are you planning to approve logging with phone as long as the data have speed errors?
2. Will you have minimum requirements for actual accuracy, or will you approve phones with poor accuracy, like Roo's?
3. How will you deal with the vast variety of phones and GPS chips in the phones?
4. Will you allow any self-written phone recording software? If not, which criteria will you use to decide if logging software is acceptable?
5. Is there a formal, publicly available protocol for device approval that anyone interested in using a phone for GPSTC could use as a guideline?
I've got plenty of "$60" Android phone lying around that I'd love to use, as well as Android logging software I've written in the past. I never bothered trying to get anything approved, since I got the impression that actual accuracy would be not just very important for approval, but also needs to be shown without any doubt. But perhaps I misunderstood what you, as the apparent gatekeeper for GPTC device approval, said.
Select to expand quoteboardsurfr said..
The only time that "error data" are every relevant is in the GPSTC challenge. You, who seems to be the person who has the final say about device approval, have made it clear that there is no chance that only devices with error data can be approved.
So as a GPSTC member, I ask:
1. Are you planning to approve logging with phone as long as the data have speed errors?
2. Will you have minimum requirements for actual accuracy, or will you approve phones with poor accuracy, like Roo's?
3. How will you deal with the vast variety of phones and GPS chips in the phones?
4. Will you allow any self-written phone recording software? If not, which criteria will you use to decide if logging software is acceptable?
5. Is there a formal, publicly available protocol for device approval that anyone interested in using a phone for GPSTC could use as a guideline?
I've got plenty of "$60" Android phone lying around that I'd love to use, as well as Android logging software I've written in the past. I never bothered trying to get anything approved, since I got the impression that actual accuracy would be not just very important for approval, but also needs to be shown without any doubt. But perhaps I misunderstood what you, as the apparent gatekeeper for GPTC device approval, said.
Wow! So unnecessarily aggressive! 
It's clear that everything is not always as it 'seems' to you. 
You have no idea of the accuracy of Roo's phone. You jumped to a conclusion based on a single image which you knew nothing about including where it came from, what phone it was and how it was being used. Very unscientific of you. 
However,
Devices that demonstrate that they can reliably produce Doppler velocity data with closely comparable levels of accuracy and consistency as the better currently approved devices, and which can produce the Doppler error validation data can be approved for use in the GPSTC.
There is a formal document of guidelines and procedures that is available on request to those who wish to apply to have their device approved.
If you have any Android phones 'laying around' that you think could meet the requirements, go ahead and knock yourself out. As said, it would have to demonstrate comparable or better, accuracy and consistency, as the better currently approved devices, and produce Doppler error data of the same type as the currently approved devices, that backed this up.
But, if you don't think it can be clearly demonstrated that it is at least as good as your own currently approved home made ublox based device, you probably should save yourself the bother.
I don't need error data, but I do need on-water display of distance, speed, and time of day, along with uploading the track for archiving.
The Timex Ironman GPS does a great job of this. When I wear it next to my GW-60 on the same arm and go out foiling, the two max speeds, two speed displays, two distance displays, and uploaded tracks are indistinguishable from each other as I observe them (without error data, of course, for the Timex).
Roo wants simple. The Timex is simplicity itself. The firmware has some adjustable settings that work just right for our sport. At USD$75 on amazon, the Timex is a great deal. I have two of them sitting here next to my computer.
Select to expand quotesailquik said..
Wow! So unnecessarily aggressive!
It's clear that everything is not always as it 'seems' to you.
Look who's talking. You jumped in on Roo's thread, even though the two of you could not have more different opinions about which GPS units should be allowed on GPSTC, to attack me. Your very next sentence is just another example of that. Select to expand quotesailquik said..
You have no idea of the accuracy of Roo's phone. You jumped to a conclusion based on a single image which you knew nothing about including where it came from, what phone it was and how it was being used. Very unscientific of you.
That's both false and aggressive. There are very good reasons to believe that phones in general, and $60 phones in particular, will have worse accuracy that devices like the Motion that have been specifically developed for high precision speed measurements. You only need to read the application note about GNSS antennas on the u-blox site. That information seems quite accurate, from what I have seen looking at both phones and the Sparkfun u-blox M9 GPS with a chip antenna.
If Roo's phone actually gives him speed accuracy estimates that are comparable to approved devices, it would be quite easy for him to post them. Select to expand quotesailquik said..
There is a formal document of guidelines and procedures that is available on request to those who wish to apply to have their device approved.
That's news to me. There was no such "formal document" when I tried to get prototype devices approved in 2018. So please send it to me, you have my email, and you know that I am currently working on a plug-and-play prototype.
Wow! You have a very strange and aggressive way of seeing things, and addressing anything the slightest bit critical of anything you say or do.
Look at yourself!
You jumped in Roo's thread to belittle him: (Since when did threads 'belong' to anyone anyhow 
)Select to expand quoteboardsurfr said..
If Roo can write a program on Android studio, I guess that pretty much proves that anyone can do so. So Roo says.
That sounds very derogatory, aggressive and totally uncalled for to me! And not even a hint that you might be trying to be humorous.
You are still very wrong about the screen image Roo posted. It's just a fact that you jumped to conclusions in ignorance. And you don't seem to be able to see it at all. You're the one who bragged about your 'scientific prowess', trying to project superiority to put me down. LOL! I think that comment was a very fair retort.
I made no value judgement on the accuracy or otherwise of any smartphone GPS or it's Doppler error data. If they meet the standards required, great! If they don't. So be it. You seem to think you know more about what I am thinking than I do.
And you seem to think you know what Roo is thinking as well. He had not indicated at any time that he was interested in getting a smartphone approved for GPSTC. (although he is certainly welcome to try if he wants to) More jumping to unsubstantiated, unwarranted conclusions.
Settle down and let it go. You are not doing yourself any favours with this carry on.
Can we just be left to discussing things that interest us now without all that rubbish?
Andrew, my thought about this thread was that it was having a dig at Peter, it's no wonder he jumped in.
I agree this should settle down, but it's certainly not all one sided.
We know Roo is a stirrer he's done it often enough to you in the past, now it seems it's Peter's turn to be targeted
Roo must be pissing himself laughing after he stirred the pot and stepped back to watch you two old keyboard warriors have a go at each other.
Select to expand quotesailquik said..
You are still very wrong about the screen image Roo posted. It's just a fact that you jumped to conclusions in ignorance.
This is a great example of how sailquick always attacks those who dare to disagree with him - grand statements that they are wrong, and then personal attacks undermining their credibility.
When u-blox announced the M9 series of GPS chips, sailquick got excited enough to post a link here, citing their marketing. When I showed data that the chip has some peculiar issues, and specific detailed data about why the accuracy may not be quite as great as the marketers make you believe, he must have hated it, since he started going into attack mode, writing:Select to expand quotesailquik said..
So far we have just seen some results that suggest ONE particular 25Hz device MAY not be anymore accurate for Doppler speed @25Hz than if running it at lower Hz. Lets try not to get carried away trying to formulate a 'Grand Theory of Everything Doppler Accuracy' on such a limited sample.
Never mind that the "one particular device" is the only chip that has 25 Hz and error data that is commercially available. Never mind that Julien Le expressed multiple times that the M9 chip is mostly marketing hype, and choose to stay with the M8 for the Motions.
So he said I was getting "carried away" and that I was trying to formulate a 'Grand Theory of Everything Doppler Accuracy', which would be complete nonsense if he had not written it to undermine my credibility. He repeated the same comment a bit later, and then stepped up his attacks. But at no point in time has he presented a single bit of data that contradicted anything I said.
Select to expand quotesailquik said..
There is a formal document of guidelines and procedures that is available on request to those who wish to apply to have their device approved.
I have requested that "formal document" here, but not received anything from you. You have my email.
Does such a document really exist? There was no such thing in May 2018, when I first tried to get a prototype approved. If there is a document that actually has been approved by the GPSTC advisory group, why do you not send it out as requested? Or better yet, post it here or on the GPSTC web site so anyone interested can see it?
Select to expand quoteJohn340 said..
Roo must be pissing himself laughing after he stirred the pot and stepped back to watch you two old keyboard warriors have a go at each other.
So true. This is one of the best trolling attempt I have ever seen. Hats off to Roo, the super troll !
Select to expand quoteboardsurfr said..sailquik said..
So far we have just seen some results that suggest ONE particular 25Hz device MAY not be anymore accurate for Doppler speed @25Hz than if running it at lower Hz. Lets try not to get carried away trying to formulate a 'Grand Theory of Everything Doppler Accuracy' on such a limited sample.
Never mind that the "one particular device" is the only chip that has 25 Hz and error data that is commercially available. Never mind that Julien Le expressed multiple times that the M9 chip is mostly marketing hype, and choose to stay with the M8 for the Motions.
I used the neo-m9 in a Gyro, Ublox changed quite some stuff, especially under the cover.
But it is the same design as a 5, 6 or 7...
For my Gyro designs it is a very nice and welcome improvement.
