Estimating pointing loss for user terminals of a satellite communications system
View Patent ↗Techniques are provided herein for monitoring the performance of a satellite communications system, including techniques for determining the pointing loss of a plurality of user terminals in the satellite communications system using the isotropic radiated power (EIRP) of the satellite.
1. A method for estimating the pointing loss for a plurality of user terminals of a satellite communications system, the method comprising:
calculating a terminal specific constant for each user terminal in the plurality of user terminals, the plurality of user terminals having a similar effective isotropic radiated power (EIRP) of the satellite;
identifying a terminal in the plurality of user terminals having a maximum terminal specific constant, the terminal associated with the maximum terminal specific constant having a minimum pointing loss in the plurality of terminals;
calculating the EIRP of the satellite using the terminal specific constant for the terminal having the maximum terminal specific constant; and
estimating the pointing loss for each of the plurality of user terminals, except for the terminal having the maximum terminal specific constant, using the EIRP of the satellite.
2. The method of claim 1 wherein the terminal specific constant is a function of a symbol rate of the link, Bolzmann's constant, path loss and a measured signal to noise ratio.
3. The method of claim 1 wherein calculating the terminal specific constant further comprises solving for the following equation:
[
C
(
n
)
]
=
[
R
sym
]
+
[
k
]
+
[
L
p
]
+
[
(
S
N
)
DL
]
,
where
1
≤
n
≤
N
wherein the notation [x] represents 10 Log 10(x), R sym represents the symbol rate of the link k represents Boltzmann's constant, L p , represents propagation loss including any rain loss, and (S/N) DL represents a downlink signal to noise ratio.
4. The method of claim 1 wherein calculating the EIRP of the satellite using an ideal gain-to-noise-temperature (G/T) and the terminal specific constant for the terminal having the maximum terminal specific constant further comprises:
calculating the value of EIRP of the satellite for using the following equation:
[
EIRP
sat
]
=
[
C
(
n
*
)
]
-
[
(
G
T
)
ideal
]
wherein the notation [x] represents 10 Log 10(x), EIRP sat represents the EIRP of the satellite, C(n*) represents the maximum terminal specific constant, and (G/T) ideal represents the ideal gain-to-noise-temperature (G/T) for the plurality of user terminals.
5. The method of claim 1 wherein estimating the pointing loss for each of the plurality of user terminals using the EIRP of the satellite further comprises:
estimating the value of pointing loss for each user terminal using the following equation:
[
L
point
(
n
)
]
=
[
EIRP
sat
]
-
[
G
T
ideal
]
-
[
C
(
n
)
]
,
where
1
≤
n
≤
N
wherein the notation [x] represents 10 Log 10(x), EIRP sat represents the EIRP of the satellite, C(n) represents the user terminal specific constant, (G/T) ideal represents the gain-to-noise-temperature (G/T) for the user terminal having the maximum terminal specific constant further comprises, and n* represents the user terminal having the maximum terminal specific constant.