How accurate is the Marvelmind indoor positioning system in noisy environments?
Can Marvelmind RTLS be accurate in noisy environments, for example, a factory floor or a concert? – clearly, yes.
Noisy where?
- Near the mobile beacon? – use NIA or MF NIA – mobile beacons emit ultrasound and don’t care about the noise. Fly noisy drones
- Or near the stationary beacons? – use IA – the stationary beacons emit ultrasound and don’t care about the noise
Typically, noise levels differ near mobile and stationary beacons.
How noisy?
- It is all about signal/noise ratio – not about the noise level
- Thus, if have a very noisy environment, you can place stationary beacons denser and closer to the mobile beacons, thus, drastically increasing signal-to-noise ratio
- Or you can try to be farther from the sources of noise, thus, decreasing the noise and once again increasing the signal-t0-noise ratio
Type of noise?
- Remember that, though, we an acoustic-based and ultrasound time-of-flight based system, we operate in ultrasound, after all. Thus, something very loud in the audible spectrum can be relatively quiet in the ultrasound and vice versa – something rather quiet in the audible spectrum can have very high ultrasound noise. The latter is rare but not impossible
- Typical bad noise: something wideband and loud – strong air conditioners, air pumps, drilling or milling and similar. Strong rain over metal – droplets produce the acoustically close to our ultrasound pulses noise
- Loud music or voice – mild or now impact
- Short bursts like gun shots – can be extremely strong but they are very short and to interfere they must badly coincide with our timing, which is unlikely
- Unexpected and nasty can be motors, AC-DC or DC-DC converters, some lamps. They can have high ultrasound noise with modest acoustic noise or no noise at all. These are rare but not impossible. Quite often, you can easily fight them by properly choosing ultrasound frequencies used in the affected areas
It is a combination of solutions
- We offer different architectures for different cases: drones – NIA or MF NIA. In some cases, IA, if you use deflectors or distances are small. People – IA. Robots and forklifts – typically, IA, but NIA and MF NIA is fine as well. Other requirements may affect more on the architecture selection
- Very sharp digital filters. As discussed above, it is not about the noise level but about the signal to noise ratio. Our sharp digital filter pass our narrow-band signal and cut off wideband noise
- Noise density drops very quickly with the frequency. Thus, loud music or speech is typically not a problem
- You can use higher ultrasound frequencies, if your environment is noise-nasty. Higher frequency bands are quieter in ultrasound
- You can even use special deflectors in special cases: Indoor positioning system for drone shows and swarms
- Optimal placement increases the signal-to-noise ratio. Direct the beacons to the right using Magnetic Holders, for example