Positioning in
multi-GNSS mode
Drawbacks
of
single-GNSS
Limited
1
of
visible
satellitesA low number
reduces the quality
of the positioningP
ositionD
ilutionO
fP
recision2
Thegeometry
of the satellites affects the position precisionHigh
PDOP
valuethe
precision
of positioningdecreases
Multipath
highly
degrades
positioning
Mass market
receivers areless precise
than high-end receivers
Multi-GNSS
solutions
Could
GPS
GLONASS
Galileo
1
of
visible
satellitesLow number
1
Galileo BeiDou GPS
8.7
4.7 4.8
New constellations
show a
low number
of visiblesatellites
The combination
ofGNSS
1
rises
the number of visiblesatellites
Galileo BeiDou Galileo + GPS BeiDou + Galileo
11.7
7.3
4.7 4.8
High
PDOP
value0 1 2 3 4 5 6 GPS Galileo BDS PD OP 0 1 2 3 4 5 6
E1/L1 E5a/L5 E5b/B2
GPS + Galileo C1 GPS + Galileo C5 Galileo + BeiDou C7
2
improve
the PDOP3
A high mask
of elevationallow
reducing
the
multipath
effectElevation mask: 30° Galileo E1 GPS L1 GPS + Galileo
3
0.9 1.5 1.1 DGPS results (3D RMS) expressed in metresMulti-GNSS
solutions are
more precise
than single-GNSS solutions
Mass market
receiversare
less precise
4
0 1 2 3 GPS Galileo BDS P reci sion on p os itio n 0 1 2 3E1/L1 E5a/L5 E5b/B2
ex pr ess ed in me tr es
Multi-GNSS
solution leads tomore precise positions
regardless of the type of receiver used
GPS + Galileo C1 GPS + Galileo C5 Galileo + BeiDou C7 DGPS result s (3D RM S)
Drawbacks
of
Differences
lead to
additional biases!
Time systems
Coordinate systems
Hardware delays
computed in DGPS mode
can be
removed
once estimated!
Constant biases:
Differential hardware delays (ISBs)
Conclusions
In challenging environments with highmultipath, multi-GNSS allow the use of higher masks of elevation, thus leading to more precise positioning results
Multi-GNSS positioning improves solutions
computed with Galileo-only and BeiDou-only satellite systems by reducing the PDOP and increasing the number of visible
satellites
In DGPS, the biases introduced by the multi-GNSS mode are constant with high-end receivers, and may be removed.