We’ve acquired a number of merchandise that discuss bands – we simply launched two merchandise that includes Quectel’s LG290P, the RTK Postcard and the Quadband Breakout Board. We even have merchandise that boast triband reception, just like the RTK Torch and the mosaic-X5. We talked about L-band a number of months in the past, the frequency at which GNSS communications are despatched from satellites. However now that we all know what bands are, why do we would like extra of them? Effectively, I’m glad you requested.
What are GNSS Bands?
GNSS alerts are broadcast over a number of frequency ranges inside the L-band, these ranges are known as “bands.” L1, L2, and L5 are widespread GPS bands that every one transmit several types of knowledge. As we talked about in our weblog about l-band, we use this frequency band as a result of these frequencies are low sufficient to penetrate atmospheric layers successfully, however excessive sufficient to supply dependable knowledge transmission, even in difficult environments like forests or city areas. The time period “band” refers to a particular vary of frequencies inside the radio spectrum. This terminology originates from radio engineering, the place your complete electromagnetic (EM) spectrum is split into frequency “bands” (e.g., VHF, UHF, L-band) based mostly on traits, regulatory allocations, and customary makes use of..
At the moment, different GNSS constellations—resembling Galileo (Europe), GLONASS (Russia), and BeiDou (China)—have their very own allotted frequency bands inside the L-band and different ranges, usually near the GPS frequencies. To forestall interference, worldwide agreements and regulatory our bodies , just like the Worldwide Telecommunication Union (ITU), coordinate these frequency allocations. Via a system of shared requirements and monitoring, GNSS constellations function side-by-side with minimal interference, and “multi-constellation” GNSS receivers can decide up alerts throughout a number of constellations to supply extremely dependable, correct positioning.
That’s a number of bands! So if every one has a particular objective and consumer group, why will we make merchandise that tout multiband reception? The brief reply is it provides you higher accuracy. The lengthy reply? Let’s get into it.
What’s so nice about multiband?
The radio spectrum is broad, starting from 3 Hz to 3000 GHz. This implies radio waves can have a wavelength as small as 1mm all the way in which as much as 100km. The frequencies used for satellite tv for pc communications had been chosen resulting from their means to penetrate by way of objects and interference, however even inside that small vary, totally different frequencies have totally different traits that make them helpful for various purposes.
Decrease frequencies penetrate by way of extra materials, however at the price of having decrease bandwidth (much less knowledge per second). Greater frequency alerts with greater power are absorbed/mirrored extra simply, however they’ll carry extra knowledge extra shortly. Radio is ideal for satellite tv for pc communications due to atmospheric home windows.
Decrease frequency radio waves penetrate the Earth’s environment extra simply due to their longer wavelengths, which implies they work together much less with the molecules within the air, permitting them to move by way of with minimal disruption, not like greater frequency waves that are extra readily absorbed or scattered by the environment’s parts.
When a receiver can soak up knowledge from all these totally different bands, it raises the chance of that receiver getting a sign, which implies a sooner repair and a extra correct repair. Extra info paints a clearer image of precision.
Dilution of Precision
Dilution of Precision is a dimensionless quantity that specifies the error in a GNSS positional repair. This quantity depends upon a receiver’s relative geometry to the satellites it is receiving alerts from. The upper this quantity, the weaker the geometry and the decrease the accuracy of the alerts.
Complicated geometry is used to calculate this quantity, however we have illustrated it for you within the determine set above. In case you’re counting on a number of satellites, their distribution within the sky is necessary – in the event that they’re too shut to one another, your sign turns into much less dependable due to the overlap between alerts.
The extra satellites and alerts you get, the higher your sign will likely be. For this reason accessing a number of bands and a number of constellations is helpful to your accuracy.
What sort of {hardware} is able to multiband reception?
All receivers obtain a base GNSS sign from at the very least one constellation; L1 (GPS), E1 (Galileo), B1 (Beidou), and so forth. Many receivers can purchase base alerts from all constellations.
Extra superior receivers can obtain a number of bands from all constellations.
Essentially the most superior receivers can obtain throughout many bands (L1/L2/L5) and constellations.
The subsequent time you are on the lookout for {hardware} in your GNSS initiatives, take into consideration what sort of accuracy you are on the lookout for, in addition to reliability in several environments. Multiband is likely to be in your future!
