Re: GPS and WM5 SirfIII problem

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Hi Mike, thanks for respond.
The position is changin while it has 3 satellites being tracked in
$GPGGA but when it increases to 4 it changes 6 times and get fixed to
41.367.843N, 369.040E very long time. This time is always very long
and it doesn't matter if I'm moving or not.
If you want that I pass you all the track I can do.

Thanks again

On 11 abr, 11:06, "Mike Edwards" <t...@xxxxxxxx> wrote:
It's hard to say from the data as none of the example NMEA strings have more
than three satellites. Do you have any more sample data that shows what the
program receives while you're having the problem? The data you've provided
does show that the position is changing.

It won't be the serial port configuration - it's pretty much either right or
wrong. If you're getting that much NMEA data, then the port is configured
correctly.

Mike.

<jonnyp...@xxxxxxxxx> wrote in message

news:1176198096.744064.243530@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Hi, I'm developing a software that use GPS that tells you what's the
closer point of your actual position of a list of points of one
database.
This software works perfectly in WM2003 and SirfII chipset.
With WM5 and SirfIII chipset works until it gets more than 3
satellites, when the position received is always the same if I go
walking, this problem doesn't occurs if I go with more velocity (by
car). The time that takes GPS to change the position seems to be
randomly, and the error can be more than 100 meters perfectly when I
go at low speed or walking (or stopped).
My surprise arrives when I do the same with other commercial programs,
and I check that happen the same. It happen me with TomTom 5.21,
Pocket CompeGPS Land, GPSLocator, etc.
I thought that may be a serialport configuration problem, but I have
tried a lot of configurations with no luck.
I've tried commercial programs in FujitsuSiemens LOOX 520, Mio
Digiwalker A701, Qteck S100 (I think) with the same results.

Had somebody the same problem?
I don't know what to do!!!

I paste a copy of my serialport configuration and the NMEA sentences
when pass 3 to 4 satellites.
Thanks a lot and sorry for my english

This is the serialport configuration

cp = new SerialPort(comport, (int)baudrate, Parity.None, 8,
StopBits.One);
cp.Handshake = Handshake.None;
cp.ReceivedBytesThreshold = 64;
cp.DtrEnable = true;
cp.RtsEnable = true;

try
{
cp.Open();
}
catch (Exception e)
{
OnError(e,"Could Not Open Com Port "+comport,"");
cp.Dispose();
setstate=States.Stopped;
return;
}
cp.ErrorReceived+=new SerialErrorReceivedEventHandler(cp_OnError);
cp.DataReceived+=new SerialDataReceivedEventHandler(cp_DataReceived);

And this is the mnea sentences (the numbers between the NMEA sentences
are the cp.BytesToRead before do the cp.ReadExisting())
64
$GPGGA,080228.638,4136.7020,N,00036.8982,E,1,03,4.4,110.9,M,51.6,M,,
0000*52
$GPGSA,A,2,22,18,19,,,,,,,,,,4.5,4.4,1.0*32
$GPRMC,080228.638,A,4136.7020,N,00036.8982,E,1.42,69.15,100407,,,A*56

64
$GPGGA,080229.638,4136.7079,N,00036.8947,E,1,03,4.4,110.9,M,51.6,M,,
0000*56
$GPGSA,A,2,22,18,19,,,,,,,,,,4.5,4.4,1.0*32
$GPRMC,080229.638,A,4136.7079,N,00036.8947,E,2.16,190.26,100407,,,A*67

64
$GPGGA,080230.638,4136.6972,N,00036.8994,E,1,03,4.4,110.9,M,51.6,M,,
0000*53
$GPGSA,A,2,22,18,19,,,,,,,,,,4.5,4.4,1.0*32
$GPRMC,080230.638,A,4136.6972,N,00036.8994,E,1.12,121.35,100407,,,A*6D

64
$GPGGA,080231.638,4136.6999,N,00036.8998,E,1,03,4.4,110.9,M,51.6,M,,
0000*5B
$GPGSA,A,2,22,18,19,,,,,,,,,,4.5,4.4,1.0*32
$GPGSV,3,1,10,19,72,327,26,22,50,066,26,18,22,045,24,03,73,117,30*79
$GPGSV,3,2,10,11,25,268,15,16,14,172,,14,13,118,,08,05,302,*73
$GPGSV,3,3,10,27,01,280,,28,00,328,*75
$GPRMC,080231.638,A,4136
80
$GPRMC,080231.638,A,4136.6999,N,00036.8998,E,0.66,128.79,100407,,,A*66
$GPGGA,080232.638,4136.6992,N,00036.9045,E,1,03,4.4,110.9,M,51.6,M,,
0000*5B
$GPGSA,A,2,22,18,19,,,,,,,,,,4.5,4.4,1.0*32
$GPRMC,080232.638,A,4136.6992,N,00036.9045,E,0.94,191.88,100407,,,A*67

64
$GPGGA,080233.642,4136.7125,N,00036.9030,E,1,03,4.4,110.9,M,51.6,M,,
0000*50
$GPGSA,A,2,22,18,19,,,,,,,,,,4.5,4.4,1.0*32
$GPRMC,080233.642,A,4136.7125,N,00036.9030,E,1.85,61.91,100407,,,A*5B

64
$GPGGA,080234.638,4136.7874,N,00036.9104,E,1,04,2.7,237.7,M,51.6,M,,
0000*5B
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPRMC,080234.638,A,4136.7874,N,00036.9104,E,1.52,154.26,100407,,,A*6B

64
$GPGGA,080235.638,4136.7847,N,00036.8985,E,1,04,2.7,223.0,M,51.6,M,,
0000*58
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPRMC,080235.638,A,4136.7847,N,00036.8985,E,2.26,157.82,100407,,,A*67

128
$GPGGA,080236.000,4136.7850,N,00036.9001,E,1,04,2.7,232.3,M,51.6,M,,
0000*57
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPGSV,3,1,10,19,72,328,30,03,72,118,22,22,50,065,31,18,22,044,23*7F
$GPGSV,3,2,10,11,25,268,22,14,14,118,,16,13,172,21,08,05,301,*77
$GPGSV,3,3,10,28,01,328,,27,00,280,*75
$GPRMC,080236.000,A,4136.7850,N,00036.9001,E,2.61,147.86,100407,,,A*6D

64
$GPGGA,080237.000,4136.7898,N,00036.9057,E,1,04,2.7,255.3,M,51.6,M,,
0000*50
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPRMC,080237.000,A,4136.7898,N,00036.9057,E,2.88,167.80,100407,,,A*68

64
$GPGGA,080238.000,4136.7900,N,00036.9062,E,1,04,2.7,258.0,M,51.6,M,,
0000*57
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPRMC,080238.000,A,4136.7900,N,00036.9062,E,1.48,167.86,100407,,,A*68

64
$GPGGA,080239.000,4136.7867,N,00036.9046,E,1,04,2.7,249.3,M,51.6,M,,
0000*53
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPRMC,080239.000,A,4136.7867,N,00036.9046,E,0.53,96.14,100407,,,A*50

64
$GPGGA,080240.000,4136.7843,N,00036.9040,E,1,04,2.7,244.4,M,51.6,M,,
0000*57
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPRMC,080240.000,A,4136.7843,N,00036.9040,E,0.00,,100407,,,A*7C

64
$GPGGA,080241.000,4136.7843,N,00036.9040,E,1,04,2.7,244.4,M,51.6,M,,
0000*56
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPGSV,3,1,10,19,72,328,28,03,72,118,29,22,50,065,27,18,22,044,23*7A
$GPGSV,3,2,10,11,25,268,21,14,14,118,,16,13,172,14,08,05,301,*72
$GPGSV,3,3,10,28,01,328,,27,00,280,*75
$GPRMC,080241.000,A,
78
$GPRMC,080241.000,A,4136.7843,N,00036.9040,E,0.00,,100407,,,A*7D
$GPGGA,080242.000,4136.7843,N,00036.9040,E,1,04,2.7,244.4,M,51.6,M,,
0000*55
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPRMC,080242.000,A,4136.7843,N,00036.9040,E,0.00,,100407,,,A*7E

64
$GPGGA,080243.000,4136.7843,N,00036.9040,E,1,04,2.7,244.4,M,51.6,M,,
0000*54
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPRMC,080243.000,A,4136.7843,N,00036.9040,E,0.00,,100407,,,A*7F

64
$GPGGA,080244.000,4136.7843,N,00036.9040,E,1,04,2.7,244.4,M,51.6,M,,
0000*53
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPRMC,080244.000,A,4136.7843,N,00036.9040,E,0.00,,100407,,,A*78

64
$GPGGA,080245.000,4136.7843,N,00036.9040,E,1,04,2.7,244.4,M,51.6,M,,
0000*52
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPRMC,080245.000,A,4136.7843,N,00036.9040,E,0.00,,100407,,,A*79

64
$GPGGA,080246.000,4136.7843,N,00036.9040,E,1,04,2.7,244.4,M,51.6,M,,
0000*51
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPGSV,3,1,10,19,72,328,27,03,72,118,29,22,50,065,21,18,22,044,24*74
$GPGSV,3,2,10,11,25,268,23,14,14,118,,16,13,172,,08,05,301,*75
$GPGSV,3,3,10,28,01,328,,27,00,280,*75
$GPRMC,080246.000,A,4136.7843,N,00036.9040,E,0.00,,100
76
$GPRMC,080246.000,A,4136.7843,N,00036.9040,E,0.00,,100407,,,A*7A
$GPGGA,080247.000,4136.7843,N,00036.9040,E,1,04,2.7,244.4,M,51.6,M,,
0000*50
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPRMC,080247.000,A,4136.7843,N,00036.9040,E,0.00,,100407,,,A*7B

64
$GPGGA,080248.000,4136.7843,N,00036.9040,E,1,04,2.7,244.4,M,51.6,M,,
0000*5F
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPRMC,080248.000,A,4136.7843,N,00036.9040,E,0.00,,100407,,,A*74

64
$GPGGA,080249.000,4136.7843,N,00036.9040,E,1,04,2.7,244.4,M,51.6,M,,
0000*5E
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPRMC,080249.000,A,4136.7843,N,00036.9040,E,0.00,,100407,,,A*75

64
$GPGGA,080250.000,4136.7843,N,00036.9040,E,1,04,2.7,244.4,M,51.6,M,,
0000*56
$GPGSA,A,3,22,03,18,19,,,,,,,,,2.9,2.7,1.0*3F
$GPRMC,080250.000,A,4136.7843,N,00036.9040,E,0.00,,100407,,,A*7D


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