Galileo OS SIS ICD.indd - GSA - Europa

● TOT m(X) is the physical satellite TOT for the signal combination X retrieved through
pseudo-range measurements
● Δt SV(X) is the satellite time correction for the signal combination X computed by
means of the time correction data retrieved from the navigation message
This satellite time correction is modelled through the following second order polynomial:
where
Δt SV(X) = a f0(X) + a f1(X)[t - t 0C(X)] + a f2(X)[t - t 0C(X)] 2 + Δt r (s) Eq. 13
● a f0(X), a f1(X), and a f2(X) are defi ned in 5.1.3
● t 0c(X) is the reference time for the clock correction as defi ned in 5.1.3
● t is the GST time in seconds
● Δt r (s) is a relativistic correction term, given by Δt r=F e A 1/2 sin(E) with
the orbital parameters (e, A 1/2, E) as described in paragraph 5.1.1 and
F = -2μ 1/2/c 2 = -4.442807309 x 10 -10 s/m 1/2
5.1.5. Broadcast Group Delay
The Broadcast Group Delay BGD(f1,f2) broadcast through the Galileo navigation
message is defi ned as follows:
TR1
− TR2
BGD(
f1,
f2
) =
2
� f � 1
Eq. 14
1 − �
�
�
�
� f2
�
where
● f 1 and f 2 denote the carrier frequencies of two Galileo signals
● TR 1 and TR 2 are the group delays of the signals whose carrier frequencies are
respectively f 1 and f 2.
A single frequency user receiver processing pseudo-ranges from the frequency f1 applies the following correction to the SV clock correction ΔtSV which is defi ned in
paragraph 5.1.4
Δ ( f ) = Δt
( f , f ) − BGD(
f , f )
Eq. 15
tSV 1 SV
48 © European Union 2010
Document subject to terms of use and disclaimers p. ii-iii
OD SIS ICD, Issue 1, February 2010
1
A single frequency user receiver processing pseudo-ranges from the frequency f2
applies the following correction to the SV clock correction ΔtSV which is defi ned in
paragraph 5.1.4
2
f
tSV 2 SV 1 2
f �
2
�
� �
�
2
1
( f ) = Δt
( f , f ) − � BGD(
f , f )
Δ 1 2
Eq. 16
� �
A dual frequency user receiver processing pseudo-ranges from the two frequencies f 1
and f 2 does not apply any additional correction for group delay. The Broadcast Group
Delay is coded according to the values stated in Table 66.
1
2