Questions about tracking high speed RC Aircraft

Hi Decawave Forum,

I have a few questions about using Decawave for a specific application. I want to attach some Decawave modules to multiple fast-moving RC aircraft to track their position at a field. I’m wondering how the modules will cope with the following:

  • Accuracy range at speeds of up to 200km/hr (with 130km/hr being an average speed), can I expect < 20cm accuracy at these speeds, if not, what accuracy should be feasible?
  • Tracking 4 or more of these tags at the same time at the above speeds, will the anchors cope with this?
  • How do the anchors deal with position calculations when the craft/tag is rapidly moving through pitch roll and yaw axis e.g. rolls and flips, does this mess with the position at all?
  • Does vertical movement hinder position calculations? I shouldn’t need to calculate height position, but if a craft gains altitude rapidly, will this mess with position calculations?
  • If I want to track these craft in a 300m * 300m space or greater, can I just cover the space in anchors? e.g. do all anchors need to see each other for calculations or only 3 anchors to triangulate at given area?



Just to answer the questions:

  1. According to DW1000 datasheet, the relative velocity can affect the transmission. This depends on the choosen communication parameters, see figure below. In practice, you may need to do a real test to check if it works for you use case.

  1. Tracking 4 Tags should be no problem. But this still depends on the update rate and your system design.

  2. I don’t see an issue here. As long as the communication maintains, the actions of the craft/tag won’t matter.

  3. As long as the radios can communicate, up or down won’t matter. By saying “I shouldn’t need to calculate height position”, If you mean you need 3D positioning, a DW1000 based RTLS should be able to do it.

  4. 300m*300m is very long distance. To achieve this, you may need to
    a) carefully choose your radio (DW1000) parameters to increase the transmission distance. Back to point 1 above, different parameters brings different performance versus relative velocity;
    b) use power amplifier to increase the transmission power, be very careful of the redio regulation;
    c) increase the density of anchors, e.g. put anchors at distance of 50m, and use 49 anchors to make a chessboard like deployment.

    In your use case, the RCs must be flying high in the air, this adds to the distance to the anchors too.

    Also I’d assume this is an outdoor use case, thus, you may need to check if this complies with your local radio regulation.


Thanks Weibo!

So it seems the modules are capable of up to 500m/s which far exceeds what we need for our application.

I tried briefly looking in the data sheet but couldn’t see anything about the refresh rate of messages e.g. how often you can get location data for a tag. I’d be interested to know that if a craft is moving at 130km/hr, how often can we expect an update on location, the forum seems to suggest update rates of 10hz+ are possible.

As for not needing to calculate height, it only needs to be a 2D solution at this stage, 3D might be handy later though.

In your example of needing 49 anchors, is that a realistic example? I’d be hoping to get away with much less anchors. 300m * 300m is a fairly large example of what we want to do, i imagine a size of 50m * 40m would be more common, for this i’d be hoping we could use less than 6 anchors, is this feasible?

Our height would typically be a maximum 80 meters.


Here we were talking about the performance of the DW1000 chip. An update rate is the feature of an RTLS system. To talk about the update rate, you have to first define the system, i.e. what location algorithm, what parameters, how many anchors etc.

The three points I mentioned above, points a) b) and c), are not all required. Sometimes you only need to implement one of them. But you may need to try them yourself and adjust a bit to find the best suitable system structure for you use case.