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Which phone / GPS receiver should I buy? Report your experiences here

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  • That works very well with Samsungs and other Android devices.
  • edited October 2014
    All fixed here, can't wait to use racechrono on track ASAP!!!

    1 question where do my lap sessions get logged?? On the phone memory?? Do I need to get a memory card for my phone???

    Also can I mount my XGPS under my tail unit or does it need to be open to the air?? Just a bit worried if I come off and it gets damaged???
  • aolaol
    edited October 2014
    Preferably in open air. But if you try it first under the tail section, make sure there's no metal between the receiver and the sky, only plastic. I've run the XGPS in race cars, always inside the car, on the dash. So there's glass in front, don't know how that compares to plastic.
  • Hi

    I just purchased a 2nd hand qstarz gps receiver however i just realized its the BT-Q818 not the 10mhz...i think its only the 1mhz model :(

    How much will this affect the accuracy of my lap times? i know that the 10mhz is preferred but i will be using it on the Phillip Island Race circuit which is a fast long track. Will it still be accurate?

    I will be using this on my Galaxy S4 phone.



  • wrcpug, with 1Hz accuracy is about 0.1s, with 10Hz about 0.01s.
  • THEORY: The difference in lap timing accuracy is not directly in relation to the update rate. If you assume the devices are 100% same but just configured to different update rates, the difference in lap timing accuracy is marginal, if the finish line is in long straight well before the braking point. RaceChrono interpolates the finish lines, so if the speed and direction does not change that much, the lap timing accuracy is virtually the same.

    Better update rate wins big when you're looking at driving line and braking points. Also devices with higher update rate seem to be generally better than devices with lower update rate. Not to mention internal GPS on virtually all phones, which have subpar antenna and reception quality.
  • great
    thanks heaps for the info guys

    Phillip island has a long fast straight with the finish line well before the 1st corner.
    If its only 0.1 of a sec difference i,m not too fussed then and the 1hz should suit my needs perfectly.

    Thanks again for the reply

  • Some more speculation.
    In practice: You are always accelerating or braking on the start/finish straigth, and gps accuracy is always "bad" when speed is not constant.
    If you are driving with a "slow" car, 100-200hp/1000-2000kg, on a long straigth, I would guess lap timing accuracy is very good even with a 1Hz gps.
    Vs motorcycle, 100-200hp/250-300kg (bike+driver), much more acceleration, then 1Hz gps gives you abaut 0.1s accuracy on lap timing.
    I have mainly been driving bikes on track. That is why my first gut feeling was "1Hz accuracy is about 0.1s, with 10Hz about 0.01s"
  • Yeah, on a very fast vehicle you're probably right. Didn't calculate how fast, but I think it needs to be very fast. There is also positional accuracy, let's say you get ~4m lap-to-lap positional accuracy on your GPS, and drive over the finish line 40 m/s. This is already +-0.1s to the lap time.
  • I have made a comparison between the QStarz-818XT and the Garmin GLO for anyone wondering which device to buy and use.

    You can read the reports here:

    http://racetrackrefugee.com/2014/04/02/garmin-glo-vs-qstarz-818xt-part-1/

    and

    http://racetrackrefugee.com/2014/06/29/garmin-glo-vs-qstarz-818xt-part-2/

    There's one more analysis to come... when I find some time!

    :)
  • Price of Garmin GLO and Qstarz BT-Q818XT are basically the same for me (~$125AUD shipped). Given that, which one would be better to buy? I am using Pro on Android 4.4 if that matters.

    FWIW, the Dual XGPS160 is almost 2x the price so not an option. Have also seen the cheap Holux type devices from DealExtreme for about $50 but not sure they'd be any good.
  • I'd buy the Garmin GLO. We have got much better results with it in Nurburgring full track on a race car. We have run Qstarz, Garmin and Dual.
  • Thanks Antti.
  • I have a BT818X, I guess it works just as well as the BT818XT (since it should be run at 5Hz not 10)? Or would the XT still be an improvement?
  • Hi Guys,
    I am planning to purchase an external GPS but cant make up my mind between QStarz-818XT and Dual XGPS 160 at the moment. I am currently in Australia and using Samsung Galaxy S Note 4 (Android version 4.4.4). My usage of RC pro and GPS will be mainly for my car on tracks (Sydney & Goulburn NSW). Any input / help would be greatly appreciated.
  • aolaol
    edited March 2015
    djdoc: Dual XGPS 160 is far better in my experience here in Europe. Must be partly due to the GLONASS support.
  • edited April 2015
    My QSTARZ BT-818XT is a bit tired from the abuse it had over the years.

    Is the XGPS160 the best device to buy or shall I look for something else ?
  • Helo, i hope you can help me fast :)
    I have a BMW M3E46 wirh obd2 and a gopro3+ what i need for this app to?
    I'm a iphone user and want to buy me a andeoid phone for this nice app :)
    I hope you can say me what i need for nice movies :)
    Thank you very much guys. Sry my english is not so good
  • Finally got to use my Garmin Glo at the track and very impressed with the accuracy. 30+ laps follow the exact same path perfectly while previously using the internal phone GPS had it going all over the place, often 50+m off track.

    Just need to get a phone holder now so I can do video as well, syncing data with gopro footage in racerender is too much effort!
  • sti04, there will be soon a beta that can remote control your GoPro create automatic sync points for the video files :)
  • Best. App. EVER!

    I'm going to sign up to the beta program ASAP :)
  • Hi to everyone.
    I have a Samsung I8150 with android 4.0.4, now i have connected a Holux M-1000 (setted to 5hz with minigps). When i use racechrono and i watch the gps settings, i see hz to 5, 4 ,3.2,1 ...etc etc.

    How can i solve?
    with the Note 2 the hz are stable to 5.

    Thanks
  • aolaol
    edited May 2015
    Unfortunately this is due to the bluetooth stack on some phone's firmware. There's nothing app developer can do about it :(

    You can try to change the GPS settings to mitigate this (there is some MTK settings app available, and probably comes with the GPS). If possible make GSA and GSV sentences only come every 1 - 10 seconds, you do not need them every 0.2 second. If you do not mind losing the "satellites gauge", you can even disable these sentences, so that only RMC and GGA are left.
  • Now I set GSA and GSV 10, and seems more stable.

    I do not know very well these settings, to use it only as a chrono can i disable them?

    thanks
  • You can disable GSA an GSV if you like, but you will lose the "satellites gauge". It's only for checking the state of GPS reception while recording (by the user), not a functional part of recording the session or lap timing.
  • I have disabled GSA and GSV, at the first attempt it was again instable, after about 20 minutes is became stable to 5hz.
    I think that is necessary switch on gps some time first for stable transmission to 5hz.
    thanks
  • Fully working with Galaxy Tab 4 T230 incl. internal GPS and SkyPro XGPS160 and ELM327 Mini blue OBDII bluetooth interface. Only exeption that i noticed is importing movs from iPhone is not supported. You need to bring it in mp4.
  • Just downloaded RC Pro and have been testing it with my HTC One (M7) and Hero 3+ (going around and around my block). Thanks for the great app!

    I am getting an XGPS160. How do everyone mount it in their cars?
  • I use velcro tape and/or 3M dual lock. One trick is to have soft side of velcro at the mounting surface, and 3M dual lock on the device, and it will stick securely enough, but is still much easier to remove...
  • I have this head unit rooted and running racechrono http://www.tradesolution.hk/e/ptxwebstore_product/1274.html

    I love race chrono but sick of the poor radio reception and boot up time of the android unit. Looking at a more man stream one.

    Are there any head units that racechrono will connect to using something like mirrorlink?
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