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    BME280 relative altitude not stable

    Established Member

    BME280 relative altitude not stable

    Hi all,
    I'm using a BME280 sensor to estimate the realtive altitude of an object, but the results are not really stable.

    This is the formula I use:


    float heightOutput_mm = (44330.77f * 1000.0f) * (1.f - pow((p1 / p0), 0.190294957f));



    • p1 -> current pressure
    • p2 -> reference pressure taken at ground level

    The problem is that keeping the object STATIC at ground level I get a very highly changing relative altitude in the range [-0.5,+0.5] m

    The sensor is configured in as suggested in the datasheet for INDOOR NAVIGATION:


    	bme280_dev.settings.osr_h = BME280_OVERSAMPLING_1X;
    	bme280_dev.settings.osr_p = BME280_OVERSAMPLING_16X;
    	bme280_dev.settings.osr_t = BME280_OVERSAMPLING_2X;
    	bme280_dev.settings.filter = BME280_FILTER_COEFF_16;
    	bme280_dev.settings.standby_time = BME280_STANDBY_TIME_0_5_MS;


    Any suggestion to inprove the stability of the readings?

    Thank you

    4 REPLIES 4
    Occasional Contributor

    Re: BME280 relative altitude not stable

    The relative accuracy for the pressure part of the BME280 is 12pa -> 96cm. The highly changing relative altitude in the range [-0.5,+0.5] m is acceptable.

    Could you please provide the ground truth and the height value you measured?

    Established Member

    Re: BME280 relative altitude not stable

    My ground truth is "zero" since I'm not measuring the altitude relatively to the sea level, but to the first value I get from the barometer (the sensor is steady).

    This is the formula that I use to estimate the relative altitude:


    float rel_height_m = ((pow((p0 / p1), 1.f/5.257f) - 1.f) * (temp + 273.15f)) / 0.0065f;



    • p0: reference pressure
    • p1: current pressure
    • temp: current sensor temperature

    Attached a 30' plot of the relative altitude


    Re: BME280 relative altitude not stable

    Hi Myzhar,

    Your plot suggests a testing time of of 30 minutes. Without a reference sensor, there is no way to real real pressure change (Building ventilation, doors/windows opening, weather, etc.) with sensor drift.

    Do you have access to a reference pressure sensor?

    Established Member

    Re: BME280 relative altitude not stable

    I have not a pressure reference sensor... I search for one. Any suggestion?