DWM1000 ranging accuracy and error

Hi everyone,

I am new to using the DWM1000 chips and I have many questions about their operation. I am using them for a university project that requires to measure the distance between an anchor and a tag. However I found that for distances more than a meter, the measurement shows that the distance is approximately 75 cm more than the actual distance. This error increases slightly for larger distances (more than 20-25 m), reaching approximately 1m (I only carried out measurements for up to 35 m for now, indoors). I am using an open source library from github and the LONGDATA_RANGE_ACCURACY mode (https://github.com/thotro/arduino-dw1000). I didn’t calibrate the antenna delay and Tx and Rx power yet. Did anyone have similar results? Are they expected? If not does anyone know the reason I’m getting these results? My measurements are shown below.

Thank you in advance for your time!

If you look at decawave app note 11 you will see that there is a signal level dependent error that will give errors with a range of around 20 cm from one extreme to the other and increases with range following roughly the pattern you describe.
If the library you are using doesn’t compensate for this then that combined with an error in your assumed antenna delay would explain everything you’re seeing.

Also ensure you keep the relative orientation of the antennas and their boards the same all the time, you can easily see orientation dependent range errors in the 20cm range.

Thanks for getting back to me! Is it expected to have an increasing error as the distance increases (or when the received power decreases)? Because the bias is both negative and positive so it is definitely not just that. When it comes to the antenna delay, could it cause this type of increasing error? Do you know the reason behind that?


You said that the error is +75 cm at 1 m and +100 cm at > 30 m.

The signal strength related errors are around -10 cm at short range and +10 cm at long range.
Antenna delay errors are fairly constant at all ranges for a given radio configuration and orientation.

So it sounds like you have an antenna delay error of about 85 cm and then the signal strength related errors on top of that.