Hi, everyone. Trying to understand the technology and its use cases…
I am trying to leverage distance measurements between two points, A and B up to a max distance up to 12 feet, with the most likely typical distance being around 6 feet. A and B would both be moving points within that radius, and the most common environment for this activity would be outdoors. I have been attempting to use bluetooth and RSSI measurements with various algorithms, but the technology is terrible for this use case.
I am encouraged by the information on the site, but trying to make sense of it. It seems Decawave may be a triangulation solution(?) and thus would require 3 points rather than 2 – and since I am outdoors with no control over the area, a third point will likely be impossible.
It sounds like what you want would be a basic TWR (Two Way Ranging) system. Two devices that exchange messages back and forth and use that information to calculate the distance between them. Unlike the Bluetooth solution the calculation is based on time of flight rather than signal strength and so should give a more reliable and accurate result assuming the direct path between the two devices isn’t blocked.
The decawave hardware can easily perform this measurement. Software/firmware support depends on the exact platform and software stack used.
Alternatively there are commercial solutions based on the decawave chip that you can purchase if you want an off the shelf solution.
Thanks Andy, really appreciate your response! What would you suggest as the cheapest way to develop a proof-of-concept? I looked at the development tools and am not sure. For my PoC, I’d just want to have an LED change color based on distance (off, color 1, color 2) and/or a small cheap speaker that chirps. I have no requirements around PoC technology stack.
Looks like the EVK1000 is almost $600, while two DMW1001 boards would run under $100. What would I be missing in the latter that the former offers? Is antenna going to play a huge role at a max distance of 12’?
I can’t really help much with the differences between the modules, the only one I used was the DWM1000 before moving to custom hardware and I’ve only every used custom firmware/drivers.
However I think it’s fairly safe to say that any unit is easily going to give you 12’ range.
The antenna will also have an impact on orientation dependent errors. This are typically under 10 cm. Assuming you can constrain the relative orientations between the units then this will normally come down to a constant offset that you can easily zero out. Getting good cm level ranges between units that can rotate relative to each other can get tricky.
Thanks again so much for your help, Andy. That’s great to hear – 10cm is WELL within the specs I’d need for a successful application (I’d be fairly happy if it were accurate even at 20cm. I won’t be able to constrain the relative orientation too much as my anchor and tag will both be moving in fairly unpredictable ways, so that will be interesting to test out.
I’ll probably try a couple of DMW1001 boards to start and see if that does what I need.
