What is Multi-GNSS?
- Multi-GNSS is short for Multiple Global Navigation
- Multi-GNSS devices calculate their position by
received simultaneously from multiple satellite constellationis.
- Most Garmin products produced before 2012
operated at the mercy of GPS, the only global navigation system available
- Performance improvements included
additional channels, high-sensitivity receivers and WAAS/EGNOS support.
- When introduced in 2011, the eTrex x0 series was the
first PND to market capable of using both GPS and GLONASS.
- These devices offered users the option to
choose between using GPS only or both GPS + GLONASS.
- Nearly a decade later, Garmin began
manufacturing GPSr that included access to the newly available Galileo
- Garmin GPSr users now had additional options:
GPS only, GPS + GLONASS, or GPS + Galileo, but never all three.
- With the advent of Multi-GNSS receivers,
simultaneous access to multiple navigation systems is now
- GNSS constellation compatibility may include: GPS, GLONASS,
Galileo, BeiDou, QZSS, and NavIC.
- More is better?
- Legacy device accuracy was primarily limited
due to poor signal sensitivity and the number of channels available.
- High-sensitivity receivers and WAAS/EGNOS
implementation greatly enhanced these products
accuracy and usability.
- Adding GLONASS effectively doubled the number
of available satellites and significantly reduced signal loss complications.
- Including support for the newer and potentially more
accurate Galileo system provided additional redundancy and precision.
- BeiDou, QZSS and NavIC also provide
additional redundancy and regional coverage.
- Variety is the spice of life!
- While a 2D location can be calculated using
just three satellite signals, an additional signal is needed for
precise clock synchronization.
- A Navigation system with 24 equally spaced satellites
orbiting the Earth should theoretically always have 12 visible for any given
time or location.
- Satellites near the horizon are most sensitive
to interference from terrestrial objects and atmospheric conditions.
- Satellites located directly overhead are
suited for determining elevation and/or altitude values.
- The remaining satellites located midway in the
sky are best used for latitude and longitude calculations.
- Given these considerations, calculating a
position in deep canyons, near tall buildings, or under dense foliage can be
- Having access to multiple navigation
can substantially improve the reported position accuracy.