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Garmin Varia RTL510 sending incorrect Target Speed

9541059
over 4 years ago

Clone of https://www.thisisant.com/forum/viewthread/7237/ : No response for a while

Hi Garmin Radar Team,

I am implementing Radar on a Stages Bike Computer and am testing with the Garmin RTL510 Model 2954, HW Rev 51, FW version 3.50 (serial 33000006678). I am noticing that the radar target speed value the sensor is reporting is not correct. It appears to be about twice the value that it should be.


I used an RTL500 and verified that this radar is returning the correct speed.

I verified the results on an Ant simulator also.

Please let me know if the Garmin RTL510 is using the conversion shown on the ANT Radar spec of speedTarget: 1bit=3.04m/s (Range 0-45.6m/s). Document number D000001664

NOTE: I retested with version 3.70 and it looks like the speed value reported is in Miles/hour instead of meters/second as per the standard.

Thanks,
Abid Esmail

  • 0 over 4 years ago

    I passed you observations on to Garmin. They confirmed that they are seeing the same thing for the RTL510 build 3.70.

    I'm sure they will fix it, but they would need to give a timeline for that work.

  • 0 over 4 years ago in reply to aweatherall

    So nobody from the garmin Varia programmers did check this before release the new 3.70 Firmware some days ago. Looks like good quality control

    . 

    https://forums.garmin.com/sports-fitness/cycling/f/varia-series/210788/new-varia-radar-rtl510-version-3-7-now-available

    Change History
    Changes made from version 3.50 to 3.70:
    Improve radar handling of very high-traffic environments.

  • 0 over 3 years ago in reply to aweatherall

    6 months and still no change. Maybe a kind reminder would help ?

  • 0 over 3 years ago in reply to catalin.onel

    Hi Catalin.onel and kd2357,

    The Lead Garmin engineer on their Radar product got back to me and he informed me that there is a difference in the RTL500 and RTL510 in terms of speed rounding, he said "The difference in the speed between the RTL500 and the RTL510 is due to different rounding internally. The RTL510 rounds up the speed where necessary to err on the side of caution."

    The engineer also mentioned that they are not actively working on improvements on the Radar.

    I retested RTL 510 with version 3.70 radar FW and there is only a difference of 1 Ant speed unit (3.04m/s or 6.80 miles/hr). I rode with the RTL510 some more with the Stages Dash2 M50/L50 and this speed difference is not very noticeable with the way we implement Radar where we don't show the actual speed of the vehicle but color code the cars.