简单GPS数据处理(gps数据分析)

int ParseGPSData(char *szGPSData, TGPSPosition *pGPSPosition)
{
// NMEA 0183格式：$GPRMC,204700,A,3403.868,N,11709.432,W,001.9,336.9,170698,013.6,E*6E
char *pBegin;
char *pTemp;
char *pTime;
char szTime[3];
char *pbAvail;
char *pLatitude;
char *pBearing;
char *pbEasting;
char *pDate;
char *pSpeed;
char szDate[3];
char *pLongitude;
char *pbNorthing;
int Y;
int X;
TGPSPosition *pGPSPosition;

memset(pGPSPosition, 0, sizeof(TGPSPosition));

pBegin = strstr(szGPSData, "$");
if (pBegin == NULL)
{
return -1;
}
pTemp = strstr(pBegin+3, "RMC");
if (pTemp != (pBegin+3))
{
return -1;
}

//时间
pBegin = strchr(pBegin, ',');
if (pBegin == NULL)
{
return -2;
}
pTime = pBegin + 1;
memset(szTime, 0, sizeof(szTime));
szTime[0] = pTime[0];
szTime[1] = pTime[1];
pGPSPosition->wFixHour = atoi(szTime);
memset(szTime, 0, sizeof(szTime));
szTime[0] = pTime[2];
szTime[1] = pTime[3];
pGPSPosition->wFixMinute = atoi(szTime);
memset(szTime, 0, sizeof(szTime));
szTime[0] = pTime[4];
szTime[1] = pTime[5];
pGPSPosition->wFixSecond = atoi(szTime);

//是否否有效的GPS
pBegin = strchr(pTime, ',');
if (pBegin == NULL)
{
return -2;
}
pbAvail = pBegin+1;
if (*pbAvail != 'A')
{
return -3;
}

//纬度
pBegin = strchr(pbAvail, ',');
if (pBegin == NULL)
{
return -5;
}
pLatitude = pBegin + 1;
pGPSPosition->dbLatitude = atof(pLatitude)/100;
Y = (int)pGPSPosition->dbLatitude;
pGPSPosition->dbLatitude = pGPSPosition->dbLatitude - Y;
pGPSPosition->dbLatitude = pGPSPosition->dbLatitude*100/60 + Y;
/*
if (thePrefile.m_dbMaxY < pGPSPosition->dbLatitude
|| thePrefile.m_dbMinY > pGPSPosition->dbLatitude)
{
return - 5;
}
*/

//是否北半球
pBegin = strchr(pLatitude, ',');
if (pBegin == NULL)
{
return -2;
}
pbNorthing = pBegin+1;
if (*pbNorthing == 'N')
{
pGPSPosition->bNorthing = XOS_TRUE;
}
else if (*pbNorthing == 'S')
{
pGPSPosition->bNorthing = XOS_FALSE;
}
else
{
return -4;
}

//经度
pBegin = strchr(pbNorthing, ',');
if (pBegin == NULL)
{
return -5;
}
pLongitude = pBegin + 1;
pGPSPosition->dbLongitude = atof(pLongitude)/100;
X = (int)pGPSPosition->dbLongitude;
pGPSPosition->dbLongitude = pGPSPosition->dbLongitude - X;
pGPSPosition->dbLongitude = pGPSPosition->dbLongitude*100/60 + X;
/*
if (thePrefile.m_dbMaxX < pGPSPosition->dbLongitude
|| thePrefile.m_dbMinX > pGPSPosition->dbLongitude)
{
return - 5;
}
*/

//是否东半球
pBegin = strchr(pLongitude, ',');
if (pBegin == NULL)
{
return -6;
}
pbEasting = pBegin+1;
if (*pbEasting == 'E')
{
pGPSPosition->bEasting = XOS_TRUE;
}
else if (*pbEasting == 'W')
{
pGPSPosition->bEasting = XOS_FALSE;
}
else
{
return -7;
}

//速度
pBegin = strchr(pbEasting, ',');
if (pBegin == NULL)
{
return -8;
}
pSpeed = pBegin + 1;
pGPSPosition->dbSpeed = atof(pSpeed)*1.852;
if (pGPSPosition->dbSpeed > 150)
{
return -9;
}

//方向
pBegin = strchr(pSpeed, ',');
if (pBegin == NULL)
{
return -10;
}
pBearing = pBegin + 1;
pGPSPosition->dbBearing = atof(pBearing);

//日期
pBegin = strchr(pBearing, ',');
if (pBegin == NULL)
{
return -11;
}
pDate = pBegin + 1;
memset(szDate, 0, sizeof(szDate));
szDate[0] = pDate[0];
szDate[1] = pDate[1];
pGPSPosition->wFixDay = atoi(szDate);
memset(szDate, 0, sizeof(szDate));
szDate[0] = pDate[2];
szDate[1] = pDate[3];
pGPSPosition->wFixMonth = atoi(szTime);
memset(szDate, 0, sizeof(szDate));
szDate[0] = pDate[4];
szDate[1] = pDate[5];
pGPSPosition->wFixYear = atoi(szDate);

if ((pGPSPosition->dbLatitude == 0) && (pGPSPosition->dbLongitude == 0))
{
return -12;
}

return 0;
}