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Positioning in multi-GNSS mode

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(1)
(2)

Positioning in

multi-GNSS mode

(3)

Drawbacks

of

single-GNSS

(4)

Limited

(5)

1

of

visible

satellites

A low number

reduces the quality

of the positioning

(6)

P

osition

D

ilution

O

f

P

recision

2

The

geometry

of the satellites affects the position precision

(7)

High

PDOP

value

the

precision

of positioning

decreases

(8)

Multipath

highly

degrades

positioning

(9)

Mass market

receivers are

less precise

than high-end receivers

(10)

Multi-GNSS

solutions

Could

(11)

GPS

GLONASS

Galileo

(12)

1

of

visible

satellites

Low number

(13)

1

Galileo BeiDou GPS

8.7

4.7 4.8

New constellations

show a

low number

of visible

satellites

(14)

The combination

of

GNSS

1

rises

the number of visible

satellites

Galileo BeiDou Galileo + GPS BeiDou + Galileo

11.7

7.3

4.7 4.8

(15)

High

PDOP

value

(16)

0 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 PDOP

(17)

3

A high mask

of elevation

allow

reducing

the

multipath

effect

(18)

Elevation mask: 30° Galileo E1 GPS L1 GPS + Galileo

3

0.9 1.5 1.1 DGPS results (3D RMS) expressed in metres

Multi-GNSS

solutions are

more precise

than single-GNSS solutions

(19)

Mass market

receivers

are

less precise

(20)

4

0 1 2 3 GPS Galileo BDS P reci sion on p os itio n 0 1 2 3

E1/L1 E5a/L5 E5b/B2

ex pr ess ed in me tr es

Multi-GNSS

solution leads to

more precise positions

regardless of the type of receiver used

GPS + Galileo C1 GPS + Galileo C5 Galileo + BeiDou C7 DGPS result s (3D RM S)

(21)

Drawbacks

of

(22)

Differences

lead to

additional biases!

Time systems

Coordinate systems

Hardware delays

(23)

computed in DGPS mode

can be

removed

once estimated!

Constant biases:

Differential hardware delays (ISBs)

(24)

Conclusions

In challenging environments with high

multipath, 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.

(25)

Contacts

Cécile Deprez

PhD Candidate

University of Liège

Email:

cecile.deprez@ulg.ac.be

René Warnant

Professor

University of Liège

Email:

rene.warnant@ulg.ac.be

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