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Garmin Tempe - accuracy?

SMICKF
over 11 years ago
Hi,

I've recently bought a Garmin Tempe to go with my Montana and it works well. It was easy to pair up and the unit is neat and small. I'm very pleased with it. I'm well aware of the limitations of siting a thermometer and how you need to put it so it's not going to be influenced by heat/cold sources so it only samples the ambient air temperature.

My query is really out of interest rather than worry.

What is the accuracy of the Garmin Tempe?

I understand that the figures aren't published. I wondered if anyone had any comparative evidence of the Tempe's accuracy? Has anyone ever compared the Tempe to a recognised accurate temperature?

I'm just a normal chap in a normal domestic environment, and I don't have access to a decent accurate thermometer, but someone has one somewhere. Has anyone every checked the Tempe?

Has Garmin ever checked them?
If so, surely they must know something.

Regards,
Mick
  • 0 over 11 years ago
    What is the accuracy of the Garmin Tempe?


    I don't have an accurate thermometer either so I can't say for certain. What I can say is that my tempe agrees with my inside thermometers (of dubious accuracy) the times I've checked.

    Back in the early 1990's I was developing an accurate (electronic) temperature sensor and we used Silicon Oil and an accurate thermometer (+/- 0.25C) to characterize our design since measuring air temperature accurately is difficult due to air currents etc.

    My guess is that the tempe uses a commercial grade IC sensor and those are typically accurate to +/- 1F in my experience.

    My 2c.
  • 0 over 11 years ago
    Someone over here did a test with a Tempe in melting ice:



    The alcohol thermometer indicated -1 degree Celcius (but I understand it should be 0 degree C, just like the GPSMAP indicates...)
  • 0 over 11 years ago
    Excellent experiment!

    Yes, indeed, melting ice is 0degC, but you'd have to stir the ice/water to make sure the temperature was evenly distributed. Either way, it seems accurate enough at zero.

    Thanks for that, now we need a mid-range temperature test.

    Regards,
    Mick
  • 0 over 11 years ago
    It doesn't matter that much how accurate the Tempe is so long as Garmin stores temperature in fit/GPX format as whole degrees C. The Tempe only has to have that level of accuracy.
    c
  • 0 over 11 years ago
    Precision, Accuracy, and Resolution

    The tempe has a Precision and Resolution of 1C/F in a GPS unit

    https://forums.garmin.com/showthread.php?30792-Oregon-450-amp-Garmin-Tempe-BUG&p=154810#post154810

    and 0.1C in track logs from my Oregon 450.

    <extensions>
    <gpxtpx:TrackPointExtension>
    <gpxtpx:atemp>28.6</gpxtpx:atemp>
    <gpxtpx:hr>116</gpxtpx:hr>
    </gpxtpx:TrackPointExtension>
    </extensions>


    The Accuracy (correctness to a known standard) is unknown at this point.
  • 0 over 11 years ago
    The accuracy at 0degC is known at this point as per the post above describing the iced water.

    I understand the differences between resolution and precision, but thank you for the link.

    The resolution can only be as good as the readout on the GPS device. My Montana only displays whole numbers, but I know the tracklog has more resolution. But hey! It doesn't matter so long as the Montana only displays whole numbers.

    My question is really aimed at trying to resolve the differences that I'm seeing comparing a thermometer on our north-facing outside wall and the readings that the car shows on the dash-board and the readings on my Montana. None of these three readings agree. I'd like to think that the Tempe and Montana are correct (within the confines of a whole number)

    Thanks and regards,
    Mick
  • 0 over 11 years ago
    Precision, Accuracy, and Resolution

    The tempe has a Precision and Resolution of 1C/F in a GPS unit

    https://forums.garmin.com/showthread.php?30792-Oregon-450-amp-Garmin-Tempe-BUG&p=154810#post154810

    and 0.1C in track logs from my Oregon 450.



    The Accuracy (correctness to a known standard) is unknown at this point.


    Interesting. For the Edge 800, the VIRB Elite, and I believe the Fenix, temperature is only recorded in whole degrees C. Good to know that some Garmin device does better. Whether or not it can support the .1 C resolution is another question.
  • 0 over 11 years ago
    Interesting. For the Edge 800, the VIRB Elite, and I believe the Fenix, temperature is only recorded in whole degrees C. Good to know that some Garmin device does better. Whether or not it can support the .1 C resolution is another question.

    The Fenix also records temperature with a .1 C resolution.
  • 0 over 11 years ago
    The Fenix also records temperature with a .1 C resolution.


    Wow, sure enough, after finding a track off my Fenix, in the GPX it records to .1 C. So the 1 C stairstepping I see in the temperature plots on Garmin Connect must be due to me uploading the .fit file instead of the GPX from my Fenix. I'll have to remember to send the GPX from now on. Thanks!
  • 0 over 11 years ago
    must be due to me uploading the .fit file

    That is correct; the temperature is stored as an integer value in the FIT format.