Forums > Windsurfing   Gps and Speed talk

GPSLogit phones speed resolution

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Created by Roo > 9 months ago, 17 Aug 2015
decrepit
WA, 12061 posts
9 Oct 2015 5:20PM
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yoyo said..
<<
All three perhaps. I thought I had ticked "screen on" but it kept going off. Mike what "min speed" setting do you use?


You need to invest in a box of Ferrero Roche chocolates and make yourself a plastic shield, that's the only way I've found to keep the display on.

Depends on wind, yesterday I set it to 20knots and that was right, as the wind increases, so does the min speed I set. It's a bit annoying hearing it all the time.

decrepit
WA, 12061 posts
9 Oct 2015 5:22PM
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John340 said..
Mike, I'll persevere with the Pixie and see if I can get some more consistent results.


It's certainly got to have everything optimal, I'll report back on how it goes on my head.

eastcoast
94 posts
28 Oct 2015 6:26AM
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i have been reading this thread and the main logit thread with great interest, for myself the talk back function is absolute gold! i sail quite testing choppy lake conditions and I'm constantly tweaking and questioning to seek that extra knot or 2 and to get live speed talked back is priceless i think - as roo said 'a game changer!'

as many others will be i will upload my gt31 to gpss etc but will get the logit/app/bag/phones for the talk back. theres been a lot of testing with experia and pixie but i see many of the samsungs have the better resolution but not much mention of them here? can anyone comment on the antennas or testing etc? i totally get the concept of getting a cheap as poss phone but hey if I'm going to spend £40 whats an extra £30 if its more accurate

p.s top work to all the people like sailquik and decrepit etc for putting in amazing efforts in testing etc to help the cause

decrepit
WA, 12061 posts
28 Oct 2015 6:34PM
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I have tested my main phone, a samsung galaxy ace3 on the road with push bike and car, and it has better satellite sensitivity than either the pixie3 or xperia e1 and has the higher resolution. If somebody gives me any other phones I'm willing to test them on land and/or sea.

eastcoast
94 posts
29 Oct 2015 2:50AM
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Thanks decrepit,
I have found samsung j1 on a special so would be great to hear if anyone has tried one, it appeared on the recommended phone list quite early so someone's tested it. it's got the resolution but in terms is satellite sensitivity would be good to know,
Think there on offer for a while and with xmas on its way may drop a touch more

Roo
780 posts
29 Oct 2015 3:51AM
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No real test of satellite sensitivity to gauge the best phone for the app. You would need to measure SNR ratio to find out but no easy way of doing that. Highest speed resolution is the most desired feature. GP3S now accepts the gps logit app for posting speeds. Best to stick the GT31 on your head as a backup.

eastcoast
94 posts
29 Oct 2015 6:05AM
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Cheers roo, for me the logit would be back up unless the 31 dies, really want it for the talk back, but would do my bit to test the phone

sailquik
VIC, 6089 posts
29 Oct 2015 12:06PM
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Since the accuracy and error in any Phone with the GPS-Logit app cannot be verified, and resolution is a different thing, best stick to posting from your GT-31 if you possibly can, and, as you say, use the App for info and feedback.

High resolution is not important at all for feedback. The ease of use of the phone and how cheap it is become the deciding factors.

Go the cheapest phone that works for you. That is why these are the ones we have been testing. Nothing to be gained from using an expensive phone except to use as a phone - which I don't.

Roo
780 posts
29 Oct 2015 9:47AM
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If GPSLogit gets more people out on the water and posting then lets go for it. The phones are cheap, easy to use, accessible and use doppler...so what's not too like. It's not about records or being accurate to 0.1 of a knot, it's about time on water. I could be recording at 10hz day in day out, but who really cares. I enjoy my windsurfing more than ever now and a lot of that is down to speedchat and the app. 99.9% of windsurfers will never be going for records so get a phone, load the app, queue your favorite tunes, point the board to the horizon and sheet in. The simpler we can make it the better.

decrepit
WA, 12061 posts
29 Oct 2015 6:17PM
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Eastcoast, Elmo has the J1, maybe you could PM him, I think I've seen him post it's results somewhere, but not sure if he also posted his GT results as well, I'll see if I can find it a bit later.

Agreed Roo, but if speed chat is telling you a few knots more than you're doing, it's not a lot of help. And with the xperia e1 that's what it can do if it's on the arm, so for me good sensitivity is the difference between being able to wear it on your arm instead of your head, and still get meaningful speed chat. The xperia e1 is even sensitive to which arm it's on, I've found it gives better results on the trailing arm, when it's a bit further away from my head. So if I'm on a starboard downwind run, my head is turned towards my right arm, if the phone is on my left arm, it's further from my head, and gives better results on the speed run.

elmo
WA, 8716 posts
29 Oct 2015 9:16PM
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I don't normally post my phone results although I have sent you some files, if anyone wants them to compare data let me know and I'll email both sets of data.

I primarily use the phone for sexy Sadie to whisper sweet nothings in my ear such as "Far queue are slow you fat basket"

decrepit
WA, 12061 posts
29 Oct 2015 9:26PM
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elmo said..
I don't normally post my phone results although I have sent you some files, if anyone wants them to compare data let me know and I'll email both sets of data.

I primarily use the phone for sexy Sadie to whisper sweet nothings in my ear such as "Far queue are slow you fat basket"


Thanks Elmo, I'll check my files, and come back a bit later.

Ok found them, silly old sieve brain forgot all about them, I think I've linked them to the GTC posts.
So we have one on the 5/9/15.
www.gpsteamchallenge.com.au/sailor_session/show?date=2015-09-05&team=2
2s 28.623, 5x10 25.242, 1hr 7.849, alpha 20.225, NM 19.621, dist 15.742
and the logit says
5/9/15 alby's logit
2s 48.1, 5x10 30.599, 1hr 8.038, alpha 20.418, NM 21.211, dist 14.886
So there's huge difference there, was this the xperia or the J1 Elmo.

and from the 12/9/15
gtc www.gpsteamchallenge.com.au/sailor_session/show?date=2015-09-12&team=2

2s 35.154, 5x10 33.741, 1hr 7.864, alpha 19.831, NM 29.382, dist 34,076

logit
2s 35.553, 5x10 33.379, 1hr 7.161, alpha 18.087, NM 29.509, dist 30.245

This looks a lot better, most of the time there's 10sats being used with an occasional drop down to 8 or 9.

The previous one is all over the place, and never settled, it's varying between 5 and 10 constantly.
So Elmo, where do you have the phone? Where ever it is doesn't look that good.

John340
QLD, 3102 posts
30 Oct 2015 8:48AM
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elmo said..
I don't normally post my phone results although I have sent you some files, if anyone wants them to compare data let me know and I'll email both sets of data.

I primarily use the phone for sexy Sadie to whisper sweet nothings in my ear such as "Far queue are slow you fat basket"


We call her "Heidi" over on Moreton Bay.!

John340
QLD, 3102 posts
30 Oct 2015 9:01AM
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Roo said..
If GPSLogit gets more people out on the water and posting then lets go for it. The phones are cheap, easy to use, accessible and use doppler...so what's not too like. It's not about records or being accurate to 0.1 of a knot, it's about time on water. I could be recording at 10hz day in day out, but who really cares. I enjoy my windsurfing more than ever now and a lot of that is down to speedchat and the app. 99.9% of windsurfers will never be going for records so get a phone, load the app, queue your favorite tunes, point the board to the horizon and sheet in. The simpler we can make it the better.


Roo,

Your logic has merit and if you are not contributing to your team results then I agree with you. Your right, if its getting more sailors on the water, go for it.

However if you aspire or regularly contribute to your GPS Team's rankings for monthly bragging rights on GPSTC, then GPSLogit is not accurate enough. The typical over read on my Xperia compared to my GT-31 is 0.5 to 1.0kt. This is not relevant when using for feedback to optimise sailing angles.. However this speed difference can mean multiple positions in a division for the monthly team and individual rankings and hence unfairly represent a good result.

bartontb
66 posts
30 Oct 2015 9:49AM
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John340 said..

Roo said..
If GPSLogit gets more people out on the water and posting then lets go for it. The phones are cheap, easy to use, accessible and use doppler...so what's not too like. It's not about records or being accurate to 0.1 of a knot, it's about time on water. I could be recording at 10hz day in day out, but who really cares. I enjoy my windsurfing more than ever now and a lot of that is down to speedchat and the app. 99.9% of windsurfers will never be going for records so get a phone, load the app, queue your favorite tunes, point the board to the horizon and sheet in. The simpler we can make it the better.



Roo,

Your logic has merit and if you are not contributing to your team results then I agree with you. Your right, if its getting more sailors on the water, go for it.

However if you aspire or regularly contribute to your GPS Team's rankings for monthly bragging rights on GPSTC, then GPSLogit is not accurate enough. The typical over read on my Xperia compared to my GT-31 is 0.5 to 1.0kt. This is not relevant when using for feedback to optimise sailing angles.. However this speed difference can mean multiple positions in a division for the monthly team and individual rankings and hence unfairly represent a good result.


John, curious what the over read on your Pixie is compared to the GT-31. I'm using the Alcatel OneTouch Evolve 2 and the results shown in GPSResults appear (to me) to be pretty clean (i.e. not spikey or noisy) and the tracks also appear to be accurate (i.e. not wandering around as shown in some previous posts). I did a few test while driving the neighborhood in a car, holding the phone out the window - when plotted on Google Earth the tracks were surprising accurate (from a position perspective).

Regarding GPSLogit - I'm a Roo disciple. He told me about the App and the hardware. It has made a huge difference for me in motivating me to get more TOW, more enjoyment, and less time standing around on the beach grousing about the wind... as I now have mini-goals each day I sail because I have solid data to track my progress. I think we are all in agreement on the logic Roo expressed.

I'm also in the 99.9% that won't be going for records and even in our small GPSTC team, probably won't be contributing to the monthly team scores unless I improve significantly, but it is fun to see how my performance compares relative to others. Would I have joined the GPSTC if the only data allowed was from the GT-31 or GT-5x devices? Probably not because of the hassle of finding the devices and the extra expense. Now that I have had a little experience with GPSTC I might be willing to spring for the extra expense, but it is a pretty high extra barrier for a lot of weekend recreational sailors. My point in this rambling - similar to Roo's (and yours) - keep the entry barrier low to encourage participation. For the 1-10% that become 'record seekers', additional hardware expense might be expected.

John340
QLD, 3102 posts
30 Oct 2015 2:38PM
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^^Barton, the one time I used the Pixie, it was located on my upper arm, it told me I was doing 46kts in 10kts of breeze on my 20 year old raceboard. I haven't used it since but I'll give it another try.

Although the Pixie has good resolution, it is a very cheap phone (I purchased for $29.50 AUD) and it has very poor satelite reception / sensitivity and hence susceptible to spikes and incorrect records. You basically get what you pay for. The Onetouch Evolve 2 sells for $100+ AUD and hence is a level or two above the Pixie. It obviously has better satellite reception and maintains the same good resolution. From your's and Roo's experience it looks like it's a good compromise between cost and accuracy. I'm glad it got you into GPSTC. With TOW and feedback on the phone you will get faster, so in the not to distant future accuracy may well become important.

I only use the phone for real time feedback and my GT-31 for posting on GPSTC, so 0.7kt accuracy of the phone is not issue for me.

bartontb
66 posts
30 Oct 2015 9:09PM
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John, thanks for the info about the pixie - I had the misconception that the Pixie and the OneTouch Evolve2 were the same phones, just branded differently.

I hope you are right about TOW and feedback will improve my numbers - It seems to have made a noticeable difference so far (one month of data). Since it is easy for me to blame my gear, I'm removing equipment from the equation. Today I'm picking up my shipment of new stuff... iSonic 90 carbon, three Neil Pryde EVO6 race sails, and assorted bits .

sailquik
VIC, 6089 posts
31 Oct 2015 12:15AM
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John340 said..
Roo said..
If GPSLogit gets more people out on the water and posting then lets go for it. The phones are cheap, easy to use, accessible and use doppler...so what's not too like. It's not about records or being accurate to 0.1 of a knot, it's about time on water. I could be recording at 10hz day in day out, but who really cares. I enjoy my windsurfing more than ever now and a lot of that is down to speedchat and the app. 99.9% of windsurfers will never be going for records so get a phone, load the app, queue your favorite tunes, point the board to the horizon and sheet in. The simpler we can make it the better.


Roo,

Your logic has merit and if you are not contributing to your team results then I agree with you. Your right, if its getting more sailors on the water, go for it.

However if you aspire or regularly contribute to your GPS Team's rankings for monthly bragging rights on GPSTC, then GPSLogit is not accurate enough. The typical over read on my Xperia compared to my GT-31 is 0.5 to 1.0kt. This is not relevant when using for feedback to optimise sailing angles.. However this speed difference can mean multiple positions in a division for the monthly team and individual rankings and hence unfairly represent a good result.


This!! ^^

"Records" are not relevant to this discussion at all. But PB's and team results are!

decrepit
WA, 12061 posts
2 Nov 2015 8:31PM
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eastcoast said..
Thanks decrepit,
I have found samsung j1 on a special so would be great to hear if anyone has tried one, it appeared on the recommended phone list quite early so someone's tested it. it's got the resolution but in terms is satellite sensitivity would be good to know,
Think there on offer for a while and with xmas on its way may drop a touch more


I've had a look at Elmo's tracks, and it appears it's not affected by the display going off, but there are still quite a few anomalies, I don't think I can recommend it.

decrepit
WA, 12061 posts
16 Nov 2015 11:39AM
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Fin has just handed me a ZTE V811 to test, he bought it from coles for $29, I didn't expect much for that price, but it does have the 0.019kt resolution

Best
0.019 knots resolution
Samsung Galaxy S5
Samsung Galaxy S3
Samsung Galaxy SIII mini
Samsung Galaxy J1
Sony Xperia Z3
Alcatel One Touch Evolve 2
Alcatel One Touch Pixie3(4)
Huawei Ascend Y330
LG L7 2
Seans Mpie Mini 809T, but so far it's only been tested on a car dashboard, and the file has plenty of gaps in it, so sensitivity is suspect. We'll know more when Sean takes it out under open skys.
ZTE V811

Worst
0.486 knots resloution
Sony Xperia Z1 compact
Sony Xperia E1
Motorola Moto X
Motorola Moto E
Galaxy Ace 3 (GT-S727ST)



seanhogan
QLD, 3424 posts
16 Nov 2015 2:21PM
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don't hold your breath for the mpie, I drowned the poor little yellow bugger !

longwinded
WA, 344 posts
16 Nov 2015 1:39PM
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Have been watching this thread with interest, and have to ask the question.
Has anybody tried using the phone with the earplugs in? Most phones use the earplug wires as an antenna for FM radio reception (85-100 Mhz). While GPS is in the 1500 and 2500 MHz ranges, wondering if there is any increase in accuracy/reduction in noise or data drop-outs.
Just curious.

decrepit
WA, 12061 posts
16 Nov 2015 6:05PM
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Long winded, yes I've used it with earphones and it doesn't help. The GPS uses a separate antenna, the two have no connection.

decrepit
WA, 12061 posts
16 Nov 2015 6:06PM
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seanhogan said..
don't hold your breath for the mpie, I drowned the poor little yellow bugger !


Bad luck Sean!

longwinded
WA, 344 posts
17 Nov 2015 10:08AM
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decrepit said..
Long winded, yes I've used it with earphones and it doesn't help. The GPS uses a separate antenna, the two have no connection.



Thanks decrepit! Thought you may have, but the dumbest question is the one you never asked!

Decided to have a bit more of a look at this and found that the gps aerial is indeed separate to the phone antenna. Having a look around on the web at phone tear-downs and gps aerial in phone is only about 20mm in length whether it is integrated into the mainboard or whether it is a component.

Found an interesting article about external add-on aerial fixes. forum.xda-developers.com/showthread.php?t=1783196

May buy a cheap phone and have a play.

decrepit
WA, 12061 posts
17 Nov 2015 6:29PM
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Great idea, but we've had a discussion about external antennas before.
Matt points out that the more cable you have the more the losses are, and of course everything has to be waterproof, and as this one is, it needs to be active, (amplified) to overcome the cable losses.
It's quite a while since I've had anything to do with radio, but there's a vague recollection of having to get the impedance matching right, I think the coax should match the impedance of the old antenna and the new one. He doesn't mention anything about that.

The best place for the antenna is on your head, that way the phone could be on your wrist where it's easiest to read, you just have to keep the cable as short as possible.

If I'm near Jcar one day, I'll drop in and have a chat with them, they may have something useful on their shelves.

decrepit
WA, 12061 posts
1 Dec 2015 7:20PM
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Looking at Saltyheavens galaxy core prime file I've added it below
Best
0.019 knots resolution
Samsung Galaxy core prime. (This looks to have good sensitivity and doesn't seem to have the display off syndrome.)
Samsung Galaxy S5
Samsung Galaxy S3
Samsung Galaxy SIII mini
Samsung Galaxy J1
Sony Xperia Z3
Alcatel One Touch Evolve 2
Alcatel One Touch Pixie3(4) (this has very bad display off syndrome, it produces big spikes in the doppler data when it turns back on)
Huawei Ascend Y330
LG L7 2
Seans Mpie Mini 809T, but so far it's only been tested on a car dashboard, and the file has plenty of gaps in it, so sensitivity is suspect. We'll know more when Sean takes it out under open skys.
ZTE V811

Worst
0.486 knots resloution
Sony Xperia Z1 compact
Sony Xperia E1
Motorola Moto X
Motorola Moto E
Galaxy Ace 3 (GT-S727ST) (this has good sensitivity and doesn't have the display off syndrome)




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Forums > Windsurfing   Gps and Speed talk


"GPSLogit phones speed resolution" started by Roo