Unsteady Device update rate

edited August 2013 in RaceChrono for Android
I used Racechrono 2.34 on a Samsung S2 Plus (i9105P) with a iBlue 747 A+ GPS receiver on a track day this week. The recorded velocity plot looks very bad due to to unsteady device update rate (0,7-5 Hz). Settings were not changed, "Do not modify settings" is unchecked. The GPS-receiver was positioned at the tail of my motorcycle (as many times before), the cell phone next to it. Probably the problem is related to the Android version, it didn't occur before updating to 4.2.2 (stock ROM).
Is there anything to do about it or should I get a new phone/receiver?

Comments

  • edited August 2013
    Only way would be to check the "Do not modify settings" and use the MTK settings app to enable only RMC, VTG and ZDA sentences (and disable the GSA, GSV and all others). You'd lose the satellites view, but should free up some bandwidth. Unfortunately some phone+GPS combinations have low bandwidth for Bluetooth serial connections for some reason (not sure if depends on Android version).
  • Thanks for the fast reply. A few weeks ago the same device combination worked perfectly, so I'm pretty sure it depends on the Android version, at least for this device combination.
    Satellites view is not important for me, if that's the only disadvantage I will stick with my old devices. Which MTK settings app do you mean? I had a look in bt747 and I'm not sure about the settings. RMC, VTG and ZDA period can be found in "Flash settings" and "NMEA Output Settings" and periods between 1 and 5 can be assigned. Which value is correct and is there a manual for the configuration of MTK receivers?
  • edited August 2013
    RMC, VTG should be 1, ZDA can be 5, I think. Others 0. Sorry, you need to google for the MTK-II chipset manual.
  • Unfortunately it's not possible to change these settings in bt747, the field "Times left" in Flash settings is 0. I will use another cell phone next time.
    Thanks for your effort and this great app!
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