GPS NMEA data using intermediate driver

[Solutionator]

Hi all,

Windows mobile SDK 6 has a FAKEGPS program wich provides fake NMEA data to the GPS. This FAKEGPS reads NMEA data from a txt file. This is perfect for testing on a emulator. But now i want to provide FAKEGPS my own txt file with a recorded trail.

For this reason i want to write a little program for my diamond which records NMEA strings into a textfile. Is this possible using the intermediate driver, or should this be done communicating to the device directly? Can anyone provide some sample code?

Thank you in advance!

[walshieau]

Hi all,

Windows mobile SDK 6 has a FAKEGPS program wich provides fake NMEA data to the GPS. This FAKEGPS reads NMEA data from a txt file. This is perfect for testing on a emulator. But now i want to provide FAKEGPS my own txt file with a recorded trail.

For this reason i want to write a little program for my diamond which records NMEA strings into a textfile. Is this possible using the intermediate driver, or should this be done communicating to the device directly? Can anyone provide some sample code?

Thank you in advance!


[DllImport("gpsapi.dll")]
static extern IntPtr GPSOpenDevice(IntPtr hNewLocationData, IntPtr hDeviceStateChange, string szDeviceName, int dwFlags);
[DllImport("gpsapi.dll")]
static extern int GPSCloseDevice(IntPtr hGPSDevice);
[DllImport("gpsapi.dll")]
static extern int GPSGetPosition(IntPtr hGPSDevice, IntPtr pGPSPosition, int dwMaximumAge, int dwFlags);
[DllImport("gpsapi.dll")]
static extern int GPSGetDeviceState(IntPtr pGPSDevice);

[Solutionator]

Thank you. I found this code also in the GPS example of the SDK.

But the GET_POSITION function on the driver does not return raw NMEA strings, it returns a struct wich is already formatted. What i would like is these raw strings:

$GPGGA,191938.767,4738.0173,N,12211.1873,W,1,06,1. 4,33.4,M,-17.2,M,0.0,0000*72
$GPGLL,4738.0173,N,12211.1873,W,191938.767,A*2A
$GPGSA,A,3,08,27,10,28,13,19,,,,,,,2.6,1.4,2.3*3E
$GPRMC,191938.767,A,4738.0173,N,12211.1873,W,0.103 296,21.60,291004,,*29
$GPGGA,191939.767,4738.0173,N,12211.1871,W,1,06,1. 4,33.4,M,-17.2,M,0.0,0000*71
$GPGLL,4738.0173,N,12211.1871,W,191939.767,A*29
$GPGSA,A,3,08,27,10,28,13,19,,,,,,,2.6,1.4,2.3*3E
$GPGSV,3,1,9,8,71,307,43,27,78,59,41,3,21,47,0,10, 26,283,32*72
$GPGSV,3,2,9,29,13,317,0,28,37,226,38,13,32,155,31 ,19,37,79,40*48
$GPGSV,3,3,9,134,0,0,0*46
$GPRMC,191939.767,A,4738.0173,N,12211.1871,W,0.097 420,25.48,291004,,*23

The MSDN site on this topic tells me there are two ways for retriving data from the intermediate driver:

1) Accessing Parsed GPS Data - I believe this is part of the example you provided. See http://msdn.microsoft.com/en-us/library/bb202033.aspx

2) Accessing Raw GPS Data - I hope this makes it possible to read all strings in NMEA. See http://msdn.microsoft.com/en-us/library/bb202097.aspx and http://msdn.microsoft.com/en-us/library/bb202019.aspx

The problem is that i don't understand what they are doing in the second example. "Open a connection to the GPS Intermediate Driver multiplexer, by calling CreateFile" Like.... how, where,what?

I found an example which listens to the GPS directly, but i prefer the intermediate driver if possible.

[walshieau]

you should check out
http://forum.xda-developers.com/showthread.php?t=394203

this project is using the intermediate driver which IS the solution you should be using.

[Solutionator]

Wauw. Great stuff. But RemoteTracker is still using intermediate driver option 1 (Accessing Parsed GPS Data).

Until I find out how I could manage to get option 2 to work (Accessing Raw GPS Data from the intermediate driver), I will extract some from the following code to get the full Raw NMEA string.

http://www.codeproject.com/KB/mobile/GpsTracerAppWMCE5.aspx

Sadly it is bypassing the intermediate driver, but hey, it works. For all other GPS actions i will use option 1 from the intermediate driver.