Global Positioning System Reference
In-Depth Information
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[24
Fi
gure 7.9 Example of multipath on the ionospheric carrier phase observable from a
ve
rtical planar surface.
(d
Lin
—
-2.
——
Lon
PgE
=
10 m
,
φ
1
= φ
2
=
0
)
α
.
When analyzing the ionospheric observable in order to map the temporal variation
of
the ionospheric delay, the multipath signature (7.18) cannot be ignored. In fact, the
m
ultipath variation of (7.14) might occasionally impact our ability to fix the integer
am
biguities, even for short baselines.
Figure 7.10 shows the effects of multipath on the pseudoranges P1 and P2, and
th
e ionospheric free function (6.91). We are using the expression for region 1 in
(7
.15) or (7.16), since we consider the case of a nearby reflection. The time delay
[24
∆τ
is
a function of the satellite elevation angle and can be computed from (7.11). The
fig
ures show the multipath for a satellite that rises
(
β =
0°
)
until it passes overhead
Fi
gure 7.10 Pseudorange multipath from a single reflection on a vertical planar surface.
(
α =
0
.
1
,d
=
5
λ
1
,
φ
1
= φ
2
=
0
)
