自己做的gps定位板搜星信号很差很慢，请教

zjwzcc

自己用gs-89 gps模块做的一个gps定位板子，板子上还附带有gprs模块，支持gps定位和gprs数据传输

现在发现gps模块搜星能力很差，板子是放在窗口的，天线用的是无源陶瓷天线(考虑到总体积尽量要求小，因此不选用室外gps天线)

现在测试发现往往开机后10-15分钟后，才能搜到4颗以上卫星。搜索能力极差，请问大家这个是不是天线部分没做好的原因还是？？



gps内置无源陶瓷天线 (原文件名:IMAG0083.jpg)

d_xin

布局的问题吧，天线放SIM卡边上。。。。。。

俺的做法是所有东西离天线有多远扔多远。

实在扔不了远的要做好抗干扰

zjwzcc

回复【楼主位】zjwzcc  
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附上当前从gps模块串口截得的数据和信号图



gps软件截取数据 (原文件名:jwd.jpg)


$GPGGA,073318.407,3020.7285,N,12006.1696,E,2,03,5.9,-7.0,M,7.0,M,2.3,0000*6B
$GPGSA,A,2,28,10,13,,,,,,,,,,6.0,5.9,1.0*31
$GPGSV,3,1,10,10,51,200,34,28,36,182,33,13,18,116,32,17,70,044,*73
$GPGSV,3,2,10,04,56,308,,02,21,271,,20,21,043,,23,20,087,*7A
$GPGSV,3,3,10,12,04,324,,42,48,144,30*72
$GPRMC,073318.407,A,3020.7285,N,12006.1696,E,0.00,173.07,141011,,,D*64
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073319.407,3020.7286,N,12006.1696,E,2,03,5.9,-7.0,M,7.0,M,2.3,0000*69
$GPRMC,073319.407,A,3020.7286,N,12006.1696,E,0.00,173.07,141011,,,D*66
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073320.407,3020.7281,N,12006.1699,E,2,03,5.9,-7.0,M,7.0,M,2.3,0000*6B
$GPRMC,073320.407,A,3020.7281,N,12006.1699,E,0.00,173.07,141011,,,D*64
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073321.407,3020.7281,N,12006.1699,E,2,03,5.9,-7.0,M,7.0,M,1.3,0000*69
$GPRMC,073321.407,A,3020.7281,N,12006.1699,E,0.00,173.07,141011,,,D*65
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073322.407,3020.7280,N,12006.1700,E,2,03,5.9,-7.0,M,7.0,M,2.3,0000*69
$GPRMC,073322.407,A,3020.7280,N,12006.1700,E,0.00,173.07,141011,,,D*66
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073323.407,3020.7281,N,12006.1700,E,2,03,5.9,-7.0,M,7.0,M,3.3,0000*68
$GPGSA,A,2,28,10,13,,,,,,,,,,5.9,5.9,1.0*3B
$GPGSV,3,1,10,10,51,200,34,28,36,182,33,13,18,116,32,17,70,044,*73
$GPGSV,3,2,10,04,56,308,,02,21,271,,20,21,043,,23,20,087,*7A
$GPGSV,3,3,10,12,04,324,,42,48,144,28*7B
$GPRMC,073323.407,A,3020.7281,N,12006.1700,E,0.00,173.07,141011,,,D*66
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073324.407,3020.7280,N,12006.1700,E,2,03,5.9,-7.0,M,7.0,M,4.3,0000*69
$GPRMC,073324.407,A,3020.7280,N,12006.1700,E,0.00,173.07,141011,,,D*60
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073325.407,3020.7276,N,12006.1701,E,2,03,5.9,-7.0,M,7.0,M,2.3,0000*66
$GPRMC,073325.407,A,3020.7276,N,12006.1701,E,0.00,173.07,141011,,,D*69
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073326.407,3020.7281,N,12006.1696,E,2,03,5.8,-7.0,M,7.0,M,2.3,0000*63
$GPRMC,073326.407,A,3020.7281,N,12006.1696,E,0.00,173.07,141011,,,D*6D
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073327.407,3020.7281,N,12006.1696,E,2,03,5.8,-7.0,M,7.0,M,2.3,0000*62
$GPRMC,073327.407,A,3020.7281,N,12006.1696,E,0.00,173.07,141011,,,D*6C
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073328.407,3020.7281,N,12006.1696,E,2,03,5.8,-7.0,M,7.0,M,3.3,0000*6C
$GPGSA,A,2,28,10,13,,,,,,,,,,5.9,5.8,1.0*3A
$GPGSV,3,1,10,10,51,200,34,28,36,182,33,13,18,116,32,17,70,044,*73
$GPGSV,3,2,10,04,56,308,,02,21,271,,20,21,043,,23,20,087,*7A
$GPGSV,3,3,10,12,04,324,,42,48,144,29*7A
$GPRMC,073328.407,A,3020.7281,N,12006.1696,E,0.00,173.07,141011,,,D*63
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073329.407,3020.7281,N,12006.1695,E,2,03,5.8,-7.0,M,7.0,M,4.3,0000*69
$GPRMC,073329.407,A,3020.7281,N,12006.1695,E,0.00,173.07,141011,,,D*61
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073330.407,3020.7281,N,12006.1695,E,2,03,5.8,-7.0,M,7.0,M,5.3,0000*60
$GPRMC,073330.407,A,3020.7281,N,12006.1695,E,0.00,173.07,141011,,,D*69
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073331.407,3020.7284,N,12006.1697,E,2,03,5.8,-7.0,M,7.0,M,1.3,0000*62
$GPRMC,073331.407,A,3020.7284,N,12006.1697,E,0.00,173.07,141011,,,D*6F
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073332.407,3020.7283,N,12006.1697,E,2,03,5.8,-7.0,M,7.0,M,2.3,0000*65
$GPRMC,073332.407,A,3020.7283,N,12006.1697,E,0.00,173.07,141011,,,D*6B
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073333.407,3020.7284,N,12006.1697,E,2,03,5.8,-7.0,M,7.0,M,3.3,0000*62
$GPGSA,A,2,28,10,13,,,,,,,,,,5.9,5.8,1.0*3A
$GPGSV,3,1,10,10,51,200,34,28,36,182,33,13,18,116,32,17,70,044,*73
$GPGSV,3,2,10,04,56,308,,02,21,271,,20,21,043,,23,20,087,*7A
$GPGSV,3,3,10,12,04,324,,$GPGGA,073456.407,3020.7294,N,12006.1694,E,2,03,5.5,-7.0,M,7.0,M,2.3,0000*68
$GPRMC,073456.407,A,3020.7294,N,12006.1694,E,0.00,173.07,141011,,,D*6B
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073457.407,3020.7296,N,12006.1694,E,2,03,5.5,-7.0,M,7.0,M,1.3,0000*68
$GPRMC,073457.407,A,3020.7296,N,12006.1694,E,0.00,173.07,141011,,,D*68
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073458.407,3020.7295,N,12006.1694,E,2,03,5.5,-7.0,M,7.0,M,2.3,0000*67
$GPGSA,A,2,28,10,13,,,,,,,,,,5.5,5.5,1.0*3B
$GPGSV,3,1,10,10,51,200,34,28,36,182,32,13,18,116,31,17,70,044,*71
$GPGSV,3,2,10,04,56,308,,02,21,271,,20,21,043,,23,20,087,*7A
$GPGSV,3,3,10,12,04,324,,42,48,144,28*7B
$GPRMC,073458.407,A,3020.7295,N,12006.1694,E,0.00,173.07,141011,,,D*64
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073459.407,3020.7295,N,12006.1694,E,2,03,5.5,-7.0,M,7.0,M,3.3,0000*67
$GPRMC,073459.407,A,3020.7295,N,12006.1694,E,0.00,173.07,141011,,,D*65
$GPVTG,173.07,T,,M,0.00,N,0.0,K,N*00
$GPGGA,073500.407,3020.7294,N,12006.1

zjwzcc

回复【1楼】d_xin  晚风
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sim卡放天线旁边有很大影响么？？

另外我看很多设计说天线要先做阻抗匹配才能用，这个具体是怎么理解？？

luok

回复【3楼】zjwzcc
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就是天线到GPS芯片之间的走线要做好阻抗匹配，不然信号衰减严重，好像是50欧吧

hanfeng000

用外置天线试试。 用ublox比较好。

zjwzcc

回复【4楼】luok  
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50欧的阻抗匹配还真不大清楚，要去查查看。。。

zjwzcc

回复【5楼】hanfeng000  
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没有外置天线，而且这东西设计不让用外置，得内置的=。=

zjwzcc

再传张板子的正面图
帮忙分析下是什么原因导致呢，干扰大么



正面图 (原文件名:jwd.jpg)

zjwzcc

天线到gps之间的走线做好阻抗匹配，具体要怎么操作？是要加另外的元器件还是？

Appcat

那板子放到完全开阔的地方试试，窗口不好说。还有，如果GPS没有内置LNA，直接用无源天线比较吃亏的。

zjwzcc

刚去楼顶测试了下，有时候可以很快定位，有时候就只能获取时间信息，看来应该是天线设计问题，请教大家了

zctc2008

你用的是内置天线，做好电路和抗干扰，以及阻抗，然后考虑的就是内置天线与成绩的匹配，如果确定其他都没问题的话，找到供应天线的厂家去调试天线（阻抗，EMI值）

eess

如果是第一次搜，10-15分钟搜到4颗貌似已经不差了
旁边楼宇高么，要移到更开阔的地方吧，愚见。