Angle / bearing of DECAWAVE device

Is there any way to derive the direction that a tag is pointing?

I suspect the answer is a resounding ‘no’, but I’m interested in any ideas experts on here might have.

For example, is there anything about the antenna’s directionality or are there any bits of squiggly waveform phase processing that could help?

I suspect this is obvious, but my use case is… in addition to knowing the position of the tags, I’d like to know the direction of a robot holding a tag. I suspect I just need to use a compass or INS of some sort, but I thought I’d explore whether there’s an RF way of doing it too, even if that’s just to counter any magnetic interference.

Any/all ideas of interest. I’ve read this and this about antenna gain.

The obvious answer would be to use a DW3000 part with phase difference of arrival. That will give you the angle for each message received. There was a DW1000 based PDoA system available for a while, I’m not sure it that’s still being sold or not.

For a single antenna system you’re probably going to have to fall back to some other form of augmentation. In theory the antenna gain pattern could give you a clue but unless you made it deliberately non-uniform the differences are probably too small to get any accuracy. And if you antenna pattern is very non-uniform then your position accuracy is probably going to be compromised. Unless you got into some fancy system where you made multiple sets of measurements while rotating a non-uniform the antenna.

Hi Andy,

Could you by any chance elaborate on how to use a single DW3000 to get the angle of arrival of a signal?


There are two versions of the DW3000 chip (ignoring package type), the DW3x10 and the DW3x20.
The parts ending in 20 have two antenna ports.

From the DW3000 user manual:

4.2 TDoA and PDoA support
The two-antenna port variants of DW3000 chip can measure the phase of incoming signal. This information can be used to help determine the direction of arrival and location of the transmission when combined with knowledge of the antenna response. More details of how this is performed will be given in an associated application note.

The “associated application note” doesn’t currently seem to be on the decawave web site but I’m guessing it will be very similar to the one for their short lived DW1000 based PDoA modules that achieved a similar result using two DW1000 chips on the same PCB. While that too seems to no longer be available from the main web page I’m sure there are some copies somewhere on the internet.

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