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Radio triangulation

MrMonkeybat
Explorer
I posted this idea on another thread but I am starting this thread just to ask the question: Does anybody know if this could actually work?

One idea i was recently considering the feasibility of is: If you had a little radio frequency absorbing sphere (or maybe a tetrahedron, cube or polyhedron) and you covered it with lots of little aerials. So that when it receives a ping from one of the base stations or trackers, by comparing the signal strength on the different facets of the ball you should be able to calculate the relative angle of the tracker, hopefully very accurately. So that with two or more base stations you will be able to triangulate the exact position of your trackers. The trackers could be simple pingers or have there own directional aerials to to provide more triangulation points.
7 REPLIES 7

raidho36
Explorer
The problem is that it's not very accurate. You get much better luck with coil sensors.

owenwp
Expert Protege
The way sixense sensors work for instance is as a set of compasses. The transmitter emits a field that mimics a bar magnet in each cardinal direction. Then the receiver behaves like a 3-dimensional compass, pointing along the field lines for each.

The geometry works out so that you can determine both position and orientation without relying on something as imprecise as field strength. It is thrown off by anything that would affect a compass, but its still far better than radio ranging.

MrMonkeybat
Explorer
And the Sixence reads the direction of the magnetic field by comparing the strength of the induction on the the 3 axis coils, so it is similar to my idea of finding the direction of a radio signal by comparing the signal strength on different aerials.

I know that attempts at triangulation by signal strength are not at accurate, and the radio waves have too long a wave length for time of flight calculation to be much more accurate than GPS, with shorter wavelengths being vulnerable to occlusion. But I have not read of any attempts at VR scale position tracking through directional triangulation of radio waves. So that is why I was pondering the possibility of creating a compact direction finding antenna.

Tgaud
Honored Guest
if I'm not mistaken, Radio is one of the best technology for rift.

But it seems radio usage need a license, somewhat different for each country, so it would be complicated

Davideus
Honored Guest
This is already developed and it works pretty well for a prototype.


MrMonkeybat
Explorer
That looks great, Oculus should buy him with their FB money. I wont bother learning radio engineering then someone has beat me to it. That thing looks damn accurate why have large companies being fooling around with magnetic fields etc.

aldrialdri
Honored Guest

That’s an interesting idea and technically possible, but there are quite a few practical challenges. Estimating direction based on signal strength (RSSI) isn’t very reliable, since radio waves are easily distorted by reflections, interference, and obstacles. You’d need extremely sensitive sensors, perfect calibration, and a clean environment. Plus, managing data from lots of directional antennas gets complex quickly. In short: it could work, but not easily—and probably not better than more established methods like UWB or time-of-flight systems. That said, it might be easier to écouter radio en ligne than to get precise angles this way!