GPRMC date ?

[antonius]

Dear Member

I tried to get date from GPRMC, but not getting any response:

code :

sscanf(str,"$GPRMC,%s,%2hhd%2hhd%2hhd,%c,%f,%c,%f,%c,%f,%c,%f,%f,%2hhd%2hhd%2hhd,%f,%c,%c,*%2s\r\n",&GPS.GPRMC.xxRMC,&GPS.GPRMC.UTC_Hour,&GPS.GPRMC.UTC_Min,&GPS.GPRMC.UTC_Sec,&GPS.GPRMC.status,&GPS.GPRMC.Latitude,&GPS.GPRMC.NS_Indicator,&GPS.GPRMC.Longitude,&GPS.GPRMC.EW_Indicator,&GPS.GPRMC.spd,&GPS.GPRMC.cog,&GPS.GPRMC.UTC_Day,&GPS.GPRMC.UTC_Month,&GPS.GPRMC.UTC_Year,&GPS.GPRMC.mv,&GPS.GPRMC.mvEW,&GPS.GPRMC.posMode,&GPS.GPRMC.CheckSum);

Am I missing something here ?

Thanks

[Tesla DeLorean]

What does sscanf() actually return?

You're going to need to debug your own code.

Suggest you test on a PC, where you feed it test strings, prove that works.

Make sure the compiler/library you are using supports sscanf() properly.

The use of 32-bit floats for latitude/longitude is not advisable.

I probably would not parse it this way, NMEA can have empty fields and variable formatting.

[antonius]

I got :

$GPRMC,112421.00,A,3208.00557,S,11559.30809,E,0.060,,010519,,,A*67

I try to print it

the code :

str=strstr((char*)GPS.rxBuffer,"$GPRMC,");
		if(str!=NULL)
		{
				memset(&GPS.GPRMC,0,sizeof(GPS.GPRMC)); //for the date page 55 u-blox6-GPS-GLONASS----
			sscanf(str,"$GPRMC,%2hhd%2hhd%2hhd.%3hd,%c,%f,%c,%f,%c,%f,%f,%2u%2u%2u,%f,%c,%c,*%2s\r\n",
			&GPS.GPRMC.UTC_Hour,&GPS.GPRMC.UTC_Min,&GPS.GPRMC.UTC_Sec,&GPS.GPRMC.UTC_MicroSec,
			&GPS.GPRMC.status,&GPS.GPRMC.Latitude,&GPS.GPRMC.NS_Indicator,&GPS.GPRMC.Longitude,
			&GPS.GPRMC.EW_Indicator,&GPS.GPRMC.spd,&GPS.GPRMC.cog,&GPS.GPRMC.UTC_Day,
			&GPS.GPRMC.UTC_Month,&GPS.GPRMC.UTC_Year,&GPS.GPRMC.mv,&GPS.GPRMC.mvEW,
			&GPS.GPRMC.posMode,&GPS.GPRMC.CheckSum);
			
 printf(str);printf("\r\n");
			printf("======================GPRMC PARSING =================\r\n");
			printf("Course over ground value: %lf degree \r\n",GPS.GPRMC.cog);
			printf("Date : %2u-%2u-%2u \r\n",GPS.GPRMC.UTC_Day,GPS.GPRMC.UTC_Month,GPS.GPRMC.UTC_Year);
			printf("====================== D O N E !=================\r\n");
		}

but I got 0-0-0 on date value,

What's missing here ??

Thanks

[Tesla DeLorean]

How many fields does sscanf() report successfully parsing?

Does it support the format methods you're using?

[antonius]

it works well on this :

if( (HAL_GetTick()-GPS.LastTime>50) && (GPS.rxIndex>0))

   {

      char   *str,*str2;

      #if (_GPS_DEBUG==1)

      printf("%s",GPS.rxBuffer);

      #endif

      str=strstr((char*)GPS.rxBuffer,"$GPGGA,");

      if(str!=NULL)

      {

         memset(&GPS.GPGGA,0,sizeof(GPS.GPGGA));

         sscanf(str,"$GPGGA,%2hhd%2hhd%2hhd.%3hd,%f,%c,%f,%c,%hhd,%hhd,%f,%f,%c,%hd,%s,*%2s\r\n",&GPS.GPGGA.UTC_Hour,&GPS.GPGGA.UTC_Min,&GPS.GPGGA.UTC_Sec,&GPS.GPGGA.UTC_MicroSec,&GPS.GPGGA.Latitude,&GPS.GPGGA.NS_Indicator,&GPS.GPGGA.Longitude,&GPS.GPGGA.EW_Indicator,&GPS.GPGGA.PositionFixIndicator,&GPS.GPGGA.SatellitesUsed,&GPS.GPGGA.HDOP,&GPS.GPGGA.MSL_Altitude,&GPS.GPGGA.MSL_Units,&GPS.GPGGA.AgeofDiffCorr,GPS.GPGGA.DiffRefStationID,GPS.GPGGA.CheckSum);

.................

   memset(&GPS.GPVTG,0,sizeof(GPS.GPVTG));

         sscanf(str,"$GPVTG,%f,%c,%f,%c,%f,%c,%f,%c,%f,*%2s\r\n",

         &GPS.GPVTG.cogt,&GPS.GPVTG.T,&GPS.GPVTG.cogm,&GPS.GPVTG.M,

         &GPS.GPVTG.knots,&GPS.GPVTG.N,&GPS.GPVTG.kph,&GPS.GPVTG.K,

         &GPS.GPVTG.posMode,&GPS.GPVTG.CheckSum);

       printf(str);printf("\r\n");

     printf("======================GPVTG PARSING =================\r\n");

         printf("Course over ground value: %f degree \r\n",GPS.GPVTG.cogt);

         printf("Speed in km/h          : %f km/h \r\n",GPS.GPVTG.kph);

         printf("====================== D O N E !=================\r\n");

}

it doesn't work with the bold area.... is it related with ==> if( (HAL_GetTick()-GPS.LastTime>50) && (GPS.rxIndex>0))) ?

or I can not use sscanf with those many fields ??

Thanks

[antonius]

Perhaps, my stack is not enough ?

[antonius]

typedef struct
{
 
	
	uint8_t			UTC_Hour;
	uint8_t			UTC_Min;
	uint8_t			UTC_Sec;
	uint16_t		UTC_MicroSec;
	
	char status;
 float Latitude;
	double			LatitudeDecimal;
	char				NS_Indicator;
	float				Longitude;
	double			LongitudeDecimal;
	char				EW_Indicator;
	float spd;
 float cog;
	
	int			UTC_Day;
	int			UTC_Month;
	int			UTC_Year;
	
	float mv;
	char mvEW;
	char posMode;
	
 char				CheckSum[2];	
	
}GPRMC_t;

[antonius]

I got from printf on line 10

$GPVTG,,T,,M,0.074,N,0.138,K,A*2A
 
$GPGGA,070050.00,3208.00548,S,11559.30824,E,1,10,0.82,36.0,M,-30.6,M,,*51
 
$GPGSA,A,3,23,26,06,09,22,01,03,16,19,07,,,1.52,0.82,1.28*05
 
$GPGSV,5,1,17,01,21,009,23,02,01,214,,03,52,084,37,04,40,264,31*7B
 
$GPGSV,5,2,17,06,33,233,35,07,40,341,25,09,54,244,28,11,04,005,*79
 
$GPGSV,5,3,17,16,15,089,12,17,06,297,,19,09,273,27,22,32,066,32*76
 
$GPGSV,5,4,17,23,60,164,35,26,12,117,21,30,09,332,19,42,41,046,*7E
 
$GPGSV,5,5,17,50,41,046,*4D
 
$GPGLL,3208.00548,S,11559.30824,E,070050.00,A,A*72
 
$GPRMC,070051.00,A,3208.00541,S,11559.30818,E,0.146,,030519,,,A*61
 
$GPVTG,,T,,M,0.146,N,0.271,K,A*24
 
$GPGGA,070051.00,3208.00541,S,11559.30818,E,1,10,0.82,36.1,M,-30.6,M,,
 

[antonius]

This what I got from function ProcessNMEALine((char*)GPS.rxBuffer)

DecodeNMEA
 
$GPRMC,074341.00,A,3208.00668,S,11559.30844,E,0.029,,030519,,,A*6E
 
$GPVTG,,T,,M,0.029,N,0.055,K,A*28
 
$GPGGA,074341.00,3208.00668,S,11559.30844,E,1,10,0.79,32.5,M,-30.6,M,,*54
 
$GPGSA,A,3,23,02,26,06,09,22,03,16,07,30,,,1.46,0.79,1.23*07
 
$GPGSV,4,1,15,01,03,012,,02,14,225,25,03,38,061,31,04,50,239,31*7A
 
$GPGSV,4,2,15,06,41,255,36,07,62,333,32,09,60,209,42,16,20,108,28*7A
 
$GPGSV,4,3,15,19,00,290,,22,17,053,20,23,49,137,35,26,09,134,20*7D
 
$GPGSV,4,4,15,30,27,326,37,42,41,046,,50,41,046,*4B
 
$GPGLL,3208.00668,S,11559.30844,E,074341.00,A,A*72
 
$GPRMC,074342.00,A,3208.00667,S,11559.30843,E,0.057,,030519,,,A*6C
 
$GPVTG,,T,,M,0.057,N,0.106,K,A*26
 
$GPGGA,074342.00,3208.00667,S,11559.30843,E,1,10,0.79,32.6,M,-30.6,M,,*5C
 
$GPGSA,A,3,23,02,26,06,09,22,03,16,07
 
Fields 13
 
#00 : $GPRMC
 
#01 : 074341.00
 
#02 : A
 
#03 : 3208.00668
 
#04 : S
 
#05 : 11559.30844
 
#06 : E
 
#07 : 0.029
 
#08 : 
 
#09 : 030519
 
#10 : 
 
#11 : 
 
#12 : A
 
 

[Vangelis Fortounas]

Hi,

scanf works for fixed length and format messages.

Depending on sentence validity or fix validity or state (A or V , 2D,3D,etc) the sentences may change length by omitting fields and change signs.

Also for different versions of NMEA output the decimal part of Latitude and Longitude can vary from 2 to 5 digits.

An option is to feed raw data to a State Machine and by byte per byte process to extract Talker, Command, Data fields, Checksum or other proprietary data. Using an atoi function can convert arithmetical fields to numbers.