How to build maps larger than 30x30m?

Marvelmind indoor positioning system supports today (Jan.2022) up to 250 beacons (stationary + mobile combined) and up to 250 submaps per map.

Each submap can be up to 1,000m2. Actually, it is a bit overstretch, because the recommended maximum distance from beacons is 30m. Nevertheless, 1,000m2 or up to 30m in absolute distance is an easy to remember rule.

Thus, it is possible to build very large maps. For example, if you have an empty warehouse, like a stadium under a roof, it is possible to cover up to 250×1000=250,000 m2. But it is a rather theoretical upper limit, because the real coverage is limited by the line of sight, first of all. Therefore, the maximum size of a map mostly depends on the complexity the area rather than on its sheer area in square meters.

See more examples how to build maps for different applications in the Placement Manual.

Remember the main requirement for the system:

  • To have tracking the mobile beacon must have a direct line of sight (hearing) to two or more stationary beacons within 30 meters for 2D or three or more for 3D

The main required defines nearly everything in the system: the number of beacons required, update rate, complexity, etc.

Maps, submaps, service zones

First of all, check the video about maps submaps, service zones, handover zones.

  • Map consists of submaps. Each map can have up to 250 submap
  • Submap comprises of 1, 2, 3, or 4 stationary beacons. If you need more than 4 beacons in a map, you must build another submap
  • One submap can have up to 250 mobile beacons. And the whole map may have up to 250 beacons … well, in fact, up to 255 beacons 🙂
  • Service zones – areas that a particular submap is responsible for tracking of mobile beacons
  • Handover zones – overlapping areas of service zones of neighboring submaps

Examples of larger maps

Maximum size of submap

Maximum size of a submap is defined by the main requirement for the system: to have tracking the mobile beacon must have a direct line of sight (hearing) to two or more stationary beacons within 30 meters for 2D or three or more for 3D.

Therefore, to be very precise, the maximum recommended area of a 2D submap is smaller than 1,000m2, because the maximum distance for 1,000m2, if the area is square-shaped is sqrt(1000) and that is more than 30m.

But the 30m limit is not a hard limit either. The system is pretty comfortably supports 33.33m maximum distance as well. Thus, an approximation of up to 1,000m2 per submap holds.

The size of a submap depends on many parameters:

  • Signal to noise ratio
  • Relative position between the beacons. For example, face to face vs. side to size. See more about the sensitivity and transmission diagrams
  • Lower frequencies (19/22/25 kHz) have lower attenuation and allow larger maps – quite easily to up to 50m in quiet areas
  • Particularly strong is 25kHz. It is a recommended frequency for the largest coverage
  • Higher frequencies – 45kHz – have much lower external noise, typically. Thus, though the 45kHz channel signal (TX+RX) can be up to 10 times weaker than that in the strongest 25kHz channel, the resulting signal/noise ratio in the channel may be about the same, since the noise level for the 25kHz could be also up 10 times higher in the same area as compared with the noise in 45kHz band
  • Middle channels – 28/31/34kHz – show middle characteristics

Further development

Today, out of the box, Marvelmind indoor positioning system supports a single modem configuration. See more about the architectures.

In upcoming released and available based on the real business cases:

  • Multi-Modem architecture – suitable to cover a campus with several buildings or a multi-floor large building
  • Multi-layer addressing supporting tens of thousands beacons – good for very large and relatively condensed maps with a single modem

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