Ku波段卫星通信雨衰计算及分析外文翻译 本文关键词：外文，卫星通信，波段，翻译，计算
Ku波段卫星通信雨衰计算及分析外文翻译 本文简介：Ku波段卫星通信雨衰计算及分析徐慨、向顺祥、黄林书电子工程系海军工程大学中国武汉摘要：使用雨量计、频谱分析仪和其他设备，根据模拟结果，测量和分析了武汉市降雨率及雨衰对Ku波段卫星通信信号的影响。分析了降雨率和雨衰的关系，并将结果与国际电信联盟无线电通信部门（ITU-R）估计值进行了比较，分析了实际测
Ku波段卫星通信雨衰计算及分析外文翻译 本文内容：
Ku波段卫星通信雨衰计算及分析
徐慨、向顺祥、黄林书
电子工程系
海军工程大学
中国武汉
摘要：使用雨量计、频谱分析仪和其他设备，根据模拟结果，测量和分析了武汉市降雨率及雨衰对Ku波段卫星通信信号的影响。分析了降雨率和雨衰的关系，并将结果与国际电信联盟无线电通信部门（
ITU-R）
估计值进行了比较，分析了实际测量值与预测值之间的不同之处。利用测得的数据，对不准确的预测模型，提出了一个改进算法，证明
ITU-R提出的预测模型是正确的。实验结果表明，有必要通过长时间的测量，获得足够的数据，来确定不同站点雨衰与降雨率之间关系。
关键词：频谱分析仪、卫星通信、雨衰、预测模型
I
引言
在卫星通信链路设计，必须计算链路的效率和冗余。因为信号可能会被吸收和过滤，所以必须提供冗余或一些对抗措施，如自适应功率控制，通过分集接收来提高链路效率。然后有两个问题：应该提供多少冗余来满足链路的有效性要求；应采取什么措施来对抗雨衰。
虽然国内外已经做了许多理论的实验研究，但是对于不同的地域链路的设计要求，实验结果不是很符合。
在论文中，通过一段时间测量武汉的降雨以及Ku波段卫星信号衰减，绘制了降雨和信号衰减之间的关系图。在比较获得的关系图和ITU-R给出的模型曲线后，证明ITU-R预测模型在不同地区之间存在一些错误，因此有必要进行一些测试，对ITU-R预测模型做一些修改。
II
测量系统的原理
图一显示了测量系统的原理。该图的左侧的是降雨衰耗估算
。下行链路信号由天线接收，并且其频率被转增下来的低噪声B转换，并且随后转到频谱。最后，通过RS-232接口，信号电压被保存到计算机。菱形天线
:0.6m，LNB振荡器频率
11300MHz
；输入频率：12.25GHZ~12.75GHZ；输出频率：950MHZ~1450MHZ；因为它是垂直极化测量信号,电源电路是采用12.5
V直流
；光谱频率范围:3KHZ~
3GHZ,10个值是每分钟收集。
右侧是降雨量的测量。这个雨量计的测量精度:0.1毫米~
7毫米/小时,运行电压:9
~
24
v直流电源提供的收集器.雨量计得到了降雨的每分钟(毫米),并发送数据在计算机中的数据收集器。当数据乘以60,那么降雨的小时是有(毫米/小时)。
测试地点：武汉，纬度:30.52°；经度：114.31°；高度：23.3米测试频率：12.333GHz;仰角的天线：48.45°。
Fig.1
实验系统结构图
III
测试结果及建模分析
A.
ITU-R降雨衰减模型
A
=g×L
（dB）
（1）
g
=
a×Rb
（dB/km）
（2）
其中，L是降雨的有效路径，
g是降雨衰减比，
R是雨量比，
a，b是相关系数，其值随频率不同变化。
B.阳光下计算放的信号的参考电平
吸光度的衰减在雨天、云和大气的变化是缓慢的。大气吸收有氧气和水蒸气组成。其中水的蒸气在不同的天气变化最大。相比较而言，吸收衰减在慢衰减中是最主要的因素。
为了去除噪声和闪烁的影响，分析了在下雨之前三天和下雨之后三天的晴朗天气所有的信号电平，得到了晴朗天气的信号参考电平As。
C.计算雨衰
取在1分钟内获得的10个信号得平均值,就得到了雨中每分钟的信号电平。然后每分钟雨衰如下：
A
=
As
-
Ar
（dB）
其中，A是指雨衰，As是晴朗天气的信号参考电平，Ar是雨中的每分钟信号电平。
D.测量结果分析
图2表示的是武汉地区2008-05-03
的降雨情况。水平轴是时间,垂直是雨衰减率。信号随时间衰减如图3所示。比较两个图，
可以得出以下结论：
（1）降雨越大，雨衰也越大。最大的降雨发生在5月3号的21:00，恰好信号衰减发生在那个时候
（2）信号衰减是不仅发生在下雨的时候，下雨后也有，因为在某些方面天空中的云也使信号发生衰减。例如，5月3日在17:00-18:00，虽然不下雨，但很明显，仍然有信号衰减。
（3）
雨衰减率期间的降雨量是相对持久。在相同的降雨，信号由降雨引起的为20的衰减分钟显然是大于一个或两分钟。
Fig2.
武汉降雨环境
Fig
3
信号衰减
E.误差分析
雨衰减和信号衰减之间的关系如图4所示。水平轴是降雨,垂直轴的是雨衰减率。“*”曲线是降雨试验测得,“e”曲线是在ITU-R提供的公式模型的基础上绘制。“△”曲线是草拟的测量值处理的最小二乘方法算法。如图所示,由ITU-R提供雨衰模型与武汉地区实际情况有很大不同，并且随着降雨量的增加误差也增大。
图4：雨衰之间的关系
Fig
5.
误差曲线
IV
改进后的算法模型
修改后的ITU-R雨衰模型：
Ap=Aitu-r—Perror
其中,Ap是修正后的雨衰减，Aitu-r是ITU-R雨衰模型预测的雨衰，Perror是修正因子。
图5是误差曲线。“*”是图4所提供的误差值曲线，曲线是由最小二乘法得到的。表达式为：
Perror=-0.0006*R*R+0.1308*R-0.1847
(dB)
其中，R是降雨量。则修改后的预测模型是:
Ap=Aitu-r—(-0.0006*R*R+0.1308*R-0.1847
)
(dB)
V.
结论
在本文中，利用相关设备测量了降雨量和Ku波段卫星通信信号衰减的值。通过比较测量值和ITU-R提供的雨衰模型，发现了测量值和预测值之间的一些不同。通过分析测量数据，提出了一个修改算法来修正ITU-R提供的雨衰模型。结果表明，随着测得的数据的数量的增加这个修改后的数据会与实际值更吻合。
信号衰减与降雨持续时间有关。同样的降雨比,持续20分钟降雨引起的信号衰减比续1分钟或2分钟降雨大得多。与此同时,真正的
情况是非常复杂的、多方面的，特别是决定雨衰减一些因素,如雨滴的大小,降水在整个衰减路径的分布、风速和温度，他们都对雨衰有影响。所以我们应该建立一个长期的观察机制，来获得降雨衰减和降雨的足够数据。这些数据将是未来研究ka波段卫星通信重要的基础。
参考文献
[
1
]
Zulfajri
B
H，Kiyotaka
F,Kenichi
I,and
Mitsuo
T。日本九州岛Ku波段雨衰测量，[
J
]。IEEE天线与无线传播快报，2002（1）：116-119.。
[2]
J.Kang，H.Echigo
K.Ohnuma，S.Nishida，R.Sato，“VSAT系统三年测量和在Ku波段雨衰卫星通道CCIR估计”，IEICE
Trans.Commun，vol.E79-B，pp.1546-1558，1997年10月。
[3]Amaya
C,Rogers
D
V亚太海事展气候变化Ka波段卫星地球链接降雨衰减特性[J]。IEEE
Trans.
On
Microwave
Theory
and
Techniques,2002,50(1):
41-45
[4]
Dissanayake
A,Allnuh
J.雨衰减和其他传播障碍以及地球卫星路径的预测模型[J].IEEE
Trans.
On
Antennas
andPropagation,1997,45(10):
1546-1557.
[5]
Dong
You
Choi，使用1小时降雨率无1分钟降雨率转换的雨衰预测模型[J]。IJCSN计算机科学国际期刊和网络安全报,2006(6):130-133
[6]
Rec.ITU-R
PN.618-8，地球电信系统空间设计方法需要传播数据和预测方法[S].ITU,Geneva,2003.
作者：许凯（M
90）出生于1965年，江苏，中国。他在2001年成为联营公司教授。他的兴趣包括波的传播，散射和卫星通信系统。
外文原文：
Measuring
and
Analyzer
of
Rain
Attenuation
for
Satellite
Communication
in
Ku
band
XU
kai,Xiang
shunxiang,Huang
Linshu
Electronics
Engineering
Department,Naval
Univ.
of
Engineering,Wu
han,China
Abstract—Using
a
rain
gauge,spectrum
analyzer
and
other
equipments,rain
rate
and
rain
attenuation
for
the
satellite
communication
signals
in
Ku
band(14/12GHz)
in
Wuhan
city
are
measured
and
analyzed
simultaneously
according
to
simulations.
The
relation
between
rain
attenuation
and
rain
rate
are
analyzed,the
result
is
compared
with
the
estimated
International
Telecommunication
Union
Radio
Communication
Sector
(ITU-R)
and
the
difference
between
the
prediction
and
the
measuration
is
analyzed.
To
the
inaccuracy
of
the
forecasting
model,a
modified
algorithm
is
presented
and
by
using
the
data
measured,the
ITU-R
forecasting
model
is
corrected.
The
experiment
results
suggest
it
is
necessary
to
measure
for
long
time
to
get
enough
data
of
the
relation
between
rain
attenuation
and
rain
rate
at
differentstations.
Keywords：spectrum
analyzer;
satellite
communication;
rain
attenuation；forecasting
model
I.
INTRODUCTION
In
the
satellite
communication
link
designing,efficiency
and
redundancy
of
link
must
be
computed.For
the
signal
may
be
absorbed
and
glittering,enough
redundancy
or
some
counter-measure
must
be
provided,such
as
the
adaptive
power
control,receiving
by
dividing
to
improve
the
efficiency
of
link[1].
Then
there
are
two
problems:
how
much
does
the
link
redundancy
should
be
provided
to
meet
the
demand
of
the
efficiency
of
the
link;
what
kind
of
counter
measure
to
rain
attenuation
should
be
taken.
Although
many
theoretical
an
experimental
study
have
been
done
in
home
or
oversea[2-5],the
results
are
still
not
so
satisfied
the
design
demand
from
various
district
links.
In
the
paper,by
measuring
on
the
rainfall
in
Wuhan
and
the
satellite
signal
attenuation
of
Ku
band
for
a
period,the
relationship
shown
in
graph
between
the
rainfall
and
its
attenuation
are
got.
After
the
comparison
between
the
result
graph
and
the
modeling
curve
given
by
the
ITU-R,it
is
proved
that
inaccuracy
exist
in
the
ITU-R
forecasting
to
the
rainfall
in
various
district
then
it
is
necessary
to
take
some
testing
and
do
some
modification.
II.
PRINCIPLE
OF
MEASUREMENT
SYSTEM
Principle
of
measurement
system
is
shown
in
fig.1.
The
left
of
the
figure
are
the
rainfall
attenuation
measurement.
The
downlink
signal
is
received
by
the
antenna
and
its
frequency
are
conversed
down
by
the
Low
Noise
B
conversion
and
then
goes
to
the
spectrum.
At
last
it
saves
the
signal
voltage
to
the
computer
through
the
RS-232
interface.
Antenna
diamond:0.6m;
LNB
oscillator
frequency:
11300MHz
；
input
frequency：12.25GHz～12.75GHz；output
frequency：950MHz～1450MHz；since
it
is
the
vertical
polarized
signal
measured,the
power
supply
circuit
is
adapted
the
12.5V
DC;
the
spectrum
frequency
range
:3KHz～3GHz，
10
values
are
collected
per
minute.
The
right
is
the
rainfall
measurement.
The
pluviometer’s
measure
precision：0.1mm～7mm/h；
denotation
error
：
one-off
rainfall
?ü10mm
，error?ü±0.2mm，one-off
rainfall
>10mm，error?ü±2%；
running
voltage：9～24V
DC
are
provided
by
the
collector.
The
pluviometer
gets
the
rainfall
per
minute（mm）and
send
the
data
to
the
computer
by
the
data
collector.
When
the
data
are
multiplied
by
60,then
the
rainfall
of
that
hour
is
got（mm/h）.
Testing
place:
Wuhan;
latitude:30.52°；longitude114.31°
；
altitude
：
23.3m
；
testing
frequency
：12.333GHz；
elevation
of
the
antenna：48.45°。
Fig.1
Experimental
system
structure
III.
TESTING
RESULT
AND
MODELING
ANALYSIS
A.
ITU-R
rainfall
attenuation
model[6]
A
=g×L
（dB）
（1）
g
=
a×Rb
（dB/km）
（2）
Where,L
is
the
rainfall
effective
path,g
is
the
ratio
of
rainfall
attenuation,R
is
the
ratio
of
rainfall,a
、b
are
correlative
coefficient.
the
value
is
varied
with
the
different
frequency.
B.
Calculating
of
the
signal
referenced
level
in
sunshine
The
change
of
absorbance
attenuation
of
rain,cloud
and
atmosphere
is
slow
change.
Atmosphere
absorption
are
made
of
oxygen
and
water
vapors,among
them
the
water
vapors
are
varied
mostly
with
the
different
weather.
Taking
one
with
another,absorption
attenuation
are
the
most
important
factors
among
slow
change
attenuations.
To
remove
the
influence
of
the
noise
and
scintilla,the
mean
is
got
from
all
the
signal
levels
in
sunshine
weather
in
the
three
days
before
and
after
the
rain,the
signal
referenced
level
in
sunshine
weather
s
A
is
obtained
then
.
C.
Calculating
the
rain
attenuation
To
take
the
average
of
the
10
signal
levels
which
are
adapted
in
one
minute,the
signal
level
per
minute
in
rain
is
obtained
.Then
the
rain
attenuation
of
the
minute
is
got
as
follows:
A
=
As
-
Ar
（dB）
（3）
Where,A
is
the
rain
attenuation，As
is
the
signal
referenced
level
in
sunshine,r
A
is
the
signal
level
per
minute
in
rain.
D.
Measuring
Result
Analysis
It
is
shown
in
figure.2
that
the
raining
circumstance
in
Wuhan
district
on
2008-05-03.The
horizontal
axes
is
time,the
vertical
is
the
rain
attenuation
ratio.
The
signal
attenuation
corresponding
with
the
time
is
shown
in
figure.3.
Compared
the
two
graphs,these
conclusion
can
be
drawn:
(1)
The
heavier
is
the
rainfall,the
greater
is
the
corresponding
rain
attenuation
ratio.When
the
maximum
of
rainfall
happened
at
about
21:00
hour
on
May
3rd,the
signal
attenuation
happened
just
at
that
time
then.
(2).The
signal
attenuation
are
not
only
happen
during
the
rain
time,but
also
after
the
rain,because
the
cloud
in
sky
also
causes
the
attenuation
in
some
respects.
For
instance,during
17:00
-18:00
on
May
3rd,though
there
is
not
rain,but
it
is
obvious
that
there
is
still
signal
attenuation.
（3）
The
rain
attenuation
ratio
is
relative
with
the
period
which
the
rainfall
is
lasting.
To
the
same
rainfall,the
signal
attenuation
which
is
caused
by
the
rainfall
for
20
minutes
is
clearly
greater
than
that
for
one
or
two
minutes.
Fig2.
Raining
circumstance
inWuhan
Fig
3
Signal
attenuation
with
the
time
E.
Error
analysis
The
relationship
between
the
rain
attenuation
and
the
signal
rain
attenuation
is
shown
in
fig.4.
The
horizontal
axes
is
rainfall,the
vertical
is
the
rain
attenuation
ratio.
“*”-curve
is
the
rainfall
measured
in
experiment,“?e”-curve
is
drawn
based
on
the
formula
provided
by
the
ITU-R
model.
“△”-curve
is
drawn
up
of
measured
value
processed
by
the
method
of
Least
Squares
Algorithm.
As
shown,the
rain
attenuation
model
provided
by
ITU-R
is
greatly
varied
from
the
real
situation
in
Wuhan
district
and
the
error
increases
with
the
rainfall’s
increasing
IV.
MODIFIED
ALGORITHM
TO
THE
MODEL
To
modify
the
rain
attenuation
model
from
ITU-R,it
is
defined
as:
Ap=Aitu-r—Perror
（4）
Where,P
A
is
the
rain
attenuation
after
compensating,ITU
R
A
-
is
the
forecasted
attenuation
from
the
ITU-R
model,error
P
is
the
compensating
factor.
Fig.5
is
the
error
curve.
“*”is
the
error
value
provided
by
the
result
of
fig.4
and
curve
is
drawn
up
by
the
method
of
Least
Squares
Algorithm,the
expression
is:
Perror=-0.0006*R*R+0.1308*R-0.1847
(dB)
Where,R
is
the
rainfall.
Then
the
modified
rainfall
forecasting
model
is:
Ap=Aitu-r—(-0.0006*R*R+0.1308*R-0.1847
)
Fig
4
Relationship
between
the
rain
attenuation
Fig
5.
The
error
curve.
V.
CONCLUSION
In
this
paper,the
rainfall
and
Ku-band
satellite
signal
attenuation
are
measured
by
using
the
equipments.
And
then
the
measured
value
is
compared
with
the
rainfall
model
provided
by
the
ITU-R
and
some
differences
are
found
between
the
measured
and
forecasted.
We
propose
a
modified
algorithm
to
modify
the
model
provided
by
ITU-R
by
analyzing
the
measured
data.
The
result
shows
that
after
modifying
data
will
be
more
consistent
with
the
real
value
with
the
increasing
of
the
measured
data
number.
Signal
attenuation
is
related
with
the
rainfall
lasting
period.
For
the
same
rainfall
ratio,the
signal
attenuation
caused
by
rainfall
lasting
for
20
minutes
is
greater
then
the
one
for
one
or
two
minutes.
Meanwhile,the
real
situation
is
very
complex
and
various,especially
some
factors
decided
the
rain
attenuation,such
as
the
dimension
of
raindrop,the
rainfall
distributing
on
the
whole
attenuation
path,wind
velocity
and
temperature,they
are
all
even.
Then
it
is
necessary
for
us
to
set
up
a
long-time
observation
mechanism
to
obtain
enough
data
about
rainfall
attenuation
and
rainfall.
These
data
will
be
the
important
foundation
in
the
research
for
the
Ka-band
satellite
communication
in
the
future.
REFERENCES
[1]Zulfajri
B
H,Kiyotaka
F,Kenichi
I,and
Mitsuo
T.Measurement
of
Ku-Band
Rain
Attenuation
Using
Several
VSATs
in
Kyushu
Island,Japan[J].
IEEE
Antennas
and
Wireless
Propagation
Letters,2002(1):
116-119.
[2]J.Kang,H.Echigo,K.Ohnuma,S.Nishida,and
R.Sato,”Three-year
measurement
by
VSAT
system
and
CCIR
estimation
for
rain
attenuation
in
Ku-band
satellite
channel,”IEICE
Trans.Commun.,vol.E79-B,pp.1546-1558,Oct.1997.
[3]Amaya
C,Rogers
D
V.
Characteristics
of
Rain
Fading
on
Ka-Band
Satellite–Earth
Links
in
a
Pacific
Maritime
Climate[J].
IEEE
Trans.
On
Microwave
Theory
and
Techniques,2002,50(1):
41-45.
[4]
Dissanayake
A,Allnuh
J.
A
Prediction
Model
that
RainAttenuation
and
other
Propagation
Impairments
alongEarth-Satellite
Path[J].
IEEE
Trans.
On
Antennas
andPropagation,1997,45(10):
1546-1557.
[5]
Dong
You
Choi,Rain
attenuation
prediction
model
by
using
the
1-hour
rain
rate
without
1-minute
rain
rate
conversion[J].IJCSNS
International
Journal
of
Computer
Science
and
Network
Security,2006(6):130-133.
[6]
Rec.ITU-R
PN.618-8,“Propagation
data
and
prediction
methods
required
for
the
design
of
earth-space
telecommunications
systems“[S].ITU,Geneva,2003.
Author:
Xu
Kai(M’90-)
was
born
in
1965,in
Jiangsu,China.
He
became
an
associate-Professor
in
2001.His
interests
include
wave
propagation,scattering
and
satellite
communication
system.1097