R&S SMW-K44, User Manual

Page: 61 / 455

Space Vehicle Configuration Satellite Navigation
61 User Manual 1178.6379.02 ─ 01
9 Space Vehicle Configuration
About satellite's (SV) power calculation
In R&S SMW, you define the power level of the individual satellites or their signals and
the power level at the RF output is calculated automatically. All power levels are set
relative to a configurable reference level . By changing this level you boost or
decrease the signal power at the R&S SMW outputs, while maintaining the power ratio
between the satellites, their signals and, if enabled, the multi-path echoes.
Absolute SV power
The absolute SV power for a given signal P
SV,signal
is calculated as follows:
P
SV,signal
= P
Ref
+ P
SV,offset
+ P
Signal,offset
+ P
PathLoss
+ P
AntPat
, where:
●
P
Ref
is the reference power level, as set with the parameter Ref. Power
●
P
SV,offset
is the global power offset of the satellite, as set with the parameter Power
Offset
●
P
Signal,offset
is signal-specific power offset, as set with the parameter Signal Power
Offset
The value reflects the differences between the signals and the frequency bands.
●
P
PathLoss
is the free space path-loss over the satellite to receiver distance (range),
included if Add Power Path-Loss > "On".
See "Free space path-loss power" on page 61.
●
P
AntPat
is the power gain of the antenna, calculated automatically, depending on the
selected body mask
See
Chapter 10.6, "Antenna Configuration Settings" , on page 87.
Free space path-loss power
P
PathLoss
is the free space path-loss over the satellite to receiver distance (range), cal-
culated as follows:
P
PathLoss
= 20log
10
(R
0
/R), where:
●
R
0
=
√
(R
Orbit,SV
2 - r 2 )
R
0
is the reference range, equal to the range of a receiver on the ground to an SV
0
at 90° elevation
●
R is the receiver to satellite range.