clear;????????????????%清除所有的變量
clc;??????????????????%關(guān)閉所有指令窗
close?all;????????????%關(guān)閉所有未隱藏的窗口
load?GPSsignal.mat????%從GPSsignal.mat中獲得所有變量到Workspace中
??????????????????????%n=length（GPSsignal）;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
SvNum=12;
%調(diào)用fGenerateCAcode3.m文件，?獲得衛(wèi)星編號為12的C/A碼
Temp=fGenerateCAcode3（SvNum）;
index1=find（Temp==0）;?%找出C/A碼中的低電平，?形成列向量存放在index1中
Temp（index1）=-ones（1length（index1））;?%返回一個與index1相同長度的一維數(shù)組?
SinWave=sin（［0:2*pi/8:2*pi*7/8］）;???%產(chǎn)生一個步進2*pi/8的正弦波
SinWave=single（SinWave）;??????????????%將SinWave矩陣轉(zhuǎn)換成單精度矩陣
GpsMatch=zeros（11）;??????????????????%生成一個1*1的零矩陣
SinWave=[SinWave?SinWave?SinWave?SinWave?SinWave];
???????GPSsignal.mat??????		　%生成一個5?ms的連續(xù)信號?
?for?i=1:length（Temp）
?????GpsMatch=[GpsMatch?Temp（1i）*SinWave];
?end
GpsMatch=GpsMatch（2:length（GpsMatch））;?%生成本地匹配信號并去掉第一個元素
n=length（GpsMatch）;
m=50000;
for?i=1:m
????Res（i）=GpsMatch*GPSsignal（1i:i+n-1）‘;
???　　　%將本地生成匹配信號GpsMatch與GPSsignal循環(huán)卷積?
end
plot（1:mRes）;??????????%圖示卷積的幅值

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Res2=abs（Res）;
for?i=1:100??????????????%該循環(huán)目的是找出Res中的最大值
［C?I］=max（Res2）;
Res2（1I）=0;
Index（1i）=I;
end;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%下面是要找到GPS?signal中的導航電文%?
%方法是檢驗GPS?signal（已被C/A?code調(diào)制過）的每個最大值處是否具有相位偏移%
w=length（GpsMatch）;
m=1;
for?i=Index（11）:w:（length（GPSsignal）-w+1）
????NavigationBit（m）=（GPSsignal（i:i+w-1）*GpsMatch′）/w;
????m=m+1;
end
NavigationCode=zeros（11）;
NavigationCode（11）=NavigationBit（11）;
m=2;Count=0;

for?i=2:length（NavigationBit）
????if（NavigationBit（1i）～=NavigationBit（1i-1））
???????????　　NavigationCode（1m）=NavigationBit（1i）;
		m=m+1;
????????????Count=0;
????else
?????????Count=Count+1;
?????????if（Count>=5）
?????????????　NavigationCode（1m）=NavigationBit（1i）;
????????????m=m+1;
????????????Count=0;
?????????end
????end
end
%%%%%我們已得到導航碼NavigationCode下面將它轉(zhuǎn)化成數(shù)字%%%%
NavigationCode=NavigationCode./abs（NavigationCode）;
index1=find（NavigationCode<0）;
NavigationCode（index1）=zeros（1length（index1））;
Table1=[0?0?0?0;
??????　?0?0?0?1;
???????　0?0?1?0;
???????　0?0?1?1;
??????　?0?1?0?0;
???????　0?1?0?1;
??????　?0?1?1?0;
　　　　?0?1?1?1;
?????????1?0?0?0;
?????????1?0?0?1;
?????????1?0?1?0;
???????1?0?1?1;
???????1?1?0?0;
???????1?1?0?1;
???????1?1?1?0;
???????1?1?1?1;];
Result=″;
for?i=1:4:length（NavigationCode）
???????TT=NavigationCode（i:i+3）;
???????MatchTable=Table1（:1:4）-[TT;TT;TT;TT;TT;TT;TT;TT;TT;TT;TT;TT;TT;TT;TT;TT];
???????MatchTable=sum（abs（MatchTable）‘）;
??????????????TempChar=‘0‘;
??????????????BestMatch=find（MatchTable==min（MatchTable））;
%用查表的方式將導航碼NavigationCode轉(zhuǎn)換成十六進制數(shù)???
???????switch?（BestMatch）
???????????case?1???????
?????????????????????????TempChar=‘0‘;
???????????case?2???????
?????????????????????????TempChar=‘1‘;
???????????case?3???????
?????????????????????????TempChar=‘2‘;
???????????case?4??????
?????????????????????????TempChar=‘3‘;
????????

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????文件????????4316??2013-07-30?15:38??huodaohangxinxi.m