What is Wittra’s core technology?
- We use 6LowPAN (6LoWPAN is an acronym of IPv6 over Low -Power Wireless Personal Area Networks.) This is a Sub GHz radio mesh radio network. We choose sub-GHz to allow for long signal hops, low power, long range and good penetration through building structures.
- The Wittra Mesh Routers will form the mesh network. The Wittra network is self-forming and self-healing (if one router fails, the network will reroute the signal to another WiTTRA Sense 360). This eliminates challenges with lost data packets.
- Wittra also employs frequency hopping as a robust solution against interference. The system will listen to a channel before communicating. If the channel has interference, it will find a clear channel. This can be considered a “polite” solution to allow other users in these bands.
- Future proof architecture allows for over-the-air firmware updates as the technology moves forward.
What is the Range of a Wittra network?
- Range is dependent on placement within the environment and the type of environment. Adding more routers and gateways can increase range significantly
- We can state an approximate 500m radius for the Gateway, and 300m per Mesh Router would be achievable figures in open air, with line of sight between the devices. Ideal placement of the Gateway is about 2m high.
- When devices are installed indoors it is then a question of how many walls or floors there are in the direct path from WiTTRA Sense 360 to Mesh Router that will determine achievable distance. Every object the radio wave passes through attenuates the signal a little.
- If the positioning feature is required then we recommend Mesh Routers are spaced every 30 to 100 metres horizontally in a grid pattern, if possible. Vertically, you can expect reliable connection through 2 floors of reinforced concrete.
- Currently our positioning is only in 2D. For 3D positioning we require the plug-in air pressure sensor and an updated map, which are coming in Q3’21
Does the position of the Mesh Router matter?
- Yes the position of the Mesh Routers is important, especially if the use case is asset tracking (positioning).
- Ideally the Mesh Routers are actually installed around the boundaries of the area or zone where positioning needs to be done. This will give the most accurate results in the calculated position of the WiTTRA Sense 360 relative to the (minimum of three) Mesh Routers.
- If the distance between Mesh Routers is more than about 30 metres (due to being placed around the zone boundaries) we would recommend one or more additional mesh routers are placed towards the middle of the zone (if positioning is required)
Can you package the Gateway to attain a higher IP rating (currently IP51)?
- Yes the Gateway can be fitted with a waterproof antenna connector as a factory option.
- An antenna cable can be used in theory; however due to FCC rules about preventing customers from using high gain antennas we cannot explicitly allow this option.
What is the operating voltage and power consumption?
- The Gateway uses a 12-Volt DC power supply (included in the kit). Current consumption is about 1 Amp, depending on what tasks the Gateway is doing.
- The Mesh Routers require an Input power during charge: 5V, 100mA. Average current consumption during normal operation: 8mA
Can you track an asset sensor if it has left the network area?
- Not at this point in time. This is a forthcoming functionality later this year that will include a few options:
- The ability to cover a much wider area (using MIOTY)
- A GPS module which can offload position data through the MIOTY network.
Can you track assets that are mobile?
- Yes we can position mobile assets within the site boundaries. We do not market this as a true RTLS (Real Time Location System) since we do not update the position in real time; however we can provide location updates down to 30 - 60 second intervals, depending on how many mobile tags are in the network
- Of course frequent position updates will affect achievable battery run-time (after which the WiTTRA Sense 360 battery will need charging via the micro-USB interface). Alternatively, a plug-in external battery pack (available Q3/2021) can be used to triple the capacity of the on-board battery.
How accurate is the positioning?
- Wittra can deliver as accurate as <1m of positioning accuracy.
- That is one of the functions of the Mesh Routers (included in the kit). A WiTTRA Sense 360 needs to be able to communicate with a minimum of three mesh routers to enable the positioning function to work with a high degree of accuracy (<1m)
- Thus for such a use case, proper site planning is important, in terms of ensuring correct Mesh Router placement to achieve proper coverage for accurate positioning.
How is positioning calculated?
- There are 2 approaches to positioning.
- RSSI (Received Signal Strength Indicator) - signal strength from tag to 3 mesh routers.
- TOF (Time of Flight) – Q3’21 we will release a firmware update to allow our patented “Time of Flight” tech. This is a significant step-up from signal strength. This will measure the time the radio signal takes from tag to mesh router. The benefit is a less dense network is required for positioning (i.e. greater distance between Mesh Routers).
Would each remote site need additional extenders/repeaters to track assets at each location?
- Yes, each site requires its own set of Gateways and routers. However, once a tag enters the new location (site), they begin sending data automatically. The new site gateway will recognize and register the tag seamlessly. Similar to a “roaming” capability.