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Added checks to discard gps data if RMC or GLL status is invalid #32

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Merged
Bigmouseears merged 6 commits into from
Aug 8, 2026
Merged

Added checks to discard gps data if RMC or GLL status is invalid #32

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81b272a
Added checks to discard gps data if RMC or GLL status is invalid
Bigmouseears May 26, 2026
a787b67
Attempt at updating unit tests
Bigmouseears Jun 2, 2026
42c0ea7
Forgot to change the num_cases initalization. Here is the commit wher…
Bigmouseears Jun 3, 2026
8f706fc
Attempt to fix test cases
Bigmouseears Jun 9, 2026
c0293a1
GLL and RMC use their last valid information in the case of invalid d…
Bigmouseears Jul 30, 2026
339c2d2
Limited scope of previous valid gll/rmc variables to the file
Bigmouseears Aug 8, 2026
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8 changes: 5 additions & 3 deletions _test/driver/gps/cases/NMEA_inputs.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -7,11 +7,13 @@
"$GPVTG,90.16,T,,M,1.75,N,3.2,K,A*31",
"$GPGGA,134733.000,5540.3231,N,01231.2938,E,1,10,0.8,24.9,M,41.5,M,,0000*6D",
"$GPRMC,134733.000,A,5540.3231,N,01231.2938,E,1.83,113.00,041112,,,A*67",
"$GPRMC,134733.000,V,0000.0000,N,00000.0000,E,1.83,000.00,041112,,,A*67",
"$GPRMC,111111.111,V,1111.1111,N,11111.1111,E,1.83,111.11,041112,,,A*67",
"$GPGGA,134734.000,5540.3233,S,01231.2941,W,1,10,0.8,23.7,M,41.5,M,,0000*6F",
"$GPRMC,134734.000,A,5540.3233,N,01231.2941,E,1.23,107.22,041112,,,A*63",
"$GPGSA,A,3,03,22,06,19,11,14,32,01,28,18,,,1.8,0.8,1.6*3F",
"$GPGLL,3953.88008971,N,10506.75318910,W,034138.00,A,D*7A",
"$GPGLL,5109.0262317,N,11401.8407304,W,202725.00,A,D*79",
"$GPGLL,,,,,,,",


"$GPGLL,0000.0000000,N,00000.0000000,W,000000.00,V,D*79",
"$GPGLL,1111.1111111,N,11111.1111111,W,111111.11,V,D*79",
"$GPGLL,,,,,,,",
4 changes: 4 additions & 0 deletions _test/driver/gps/cases/gps_parse_actual.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -7,9 +7,13 @@
0.000000,0.000000,0.000000,0.000000,0.000000,0.000000,0,0,0,0,0.000000,0.000000,0,0,1.750000,0.000000,0,0,90.160004,T,0.000000,M,N,3.200000,K
55.672054,12.521564,0.000000,1231.293823,5540.323242,134733.000000,N,E,1,10,0.800000,24.900000,M,0,0.000000,0.000000,0,0,0.000000,0,0.000000,0,0,0.000000,0
55.672054,12.521564,0.000000,1231.293823,5540.323242,134733.000000,N,E,0,0,0.000000,0.000000,0,A,1.830000,113.000000,41112,0,0.000000,0,0.000000,0,0,0.000000,0
55.672054,12.521564,0.000000,1231.293823,5540.323242,134733.000000,N,E,0,0,0.000000,0.000000,0,V,1.830000,113.000000,41112,0,0.000000,0,0.000000,0,0,0.000000,0
55.672054,12.521564,0.000000,1231.293823,5540.323242,134733.000000,N,E,0,0,0.000000,0.000000,0,V,1.830000,113.000000,41112,0,0.000000,0,0.000000,0,0,0.000000,0
-55.672054,-12.521567,0.000000,1231.294067,5540.323242,134734.000000,S,W,1,10,0.800000,23.700001,M,0,0.000000,0.000000,0,0,0.000000,0,0.000000,0,0,0.000000,0
55.672054,12.521567,0.000000,1231.294067,5540.323242,134734.000000,N,E,0,0,0.000000,0.000000,0,A,1.230000,107.220001,41112,0,0.000000,0,0.000000,0,0,0.000000,0
0.000000,0.000000,0.000000,0.000000,0.000000,0.000000,0,0,0,0,0.000000,0.000000,0,0,0.000000,0.000000,0,0,0.000000,0,0.000000,0,0,0.000000,0
39.898003,-105.112549,0.000000,10506.752930,3953.880127,34138.000000,N,W,0,0,0.000000,0.000000,0,0,0.000000,0.000000,0,A,0.000000,0,0.000000,0,0,0.000000,0
51.150440,-114.030678,0.000000,11401.840820,5109.026367,202725.000000,N,W,0,0,0.000000,0.000000,0,0,0.000000,0.000000,0,A,0.000000,0,0.000000,0,0,0.000000,0
51.150440,-114.030678,0.000000,11401.840820,5109.026367,202725.000000,N,W,0,0,0.000000,0.000000,0,0,0.000000,0.000000,0,V,0.000000,0,0.000000,0,0,0.000000,0
51.150440,-114.030678,0.000000,11401.840820,5109.026367,202725.000000,N,W,0,0,0.000000,0.000000,0,0,0.000000,0.000000,0,V,0.000000,0,0.000000,0,0,0.000000,0
0.000000,0.000000,0.000000,0.000000,0.000000,0.000000,0,0,0,0,0.000000,0.000000,0,0,0.000000,0.000000,0,0,0.000000,0,0.000000,0,0,0.000000,0
4 changes: 4 additions & 0 deletions _test/driver/gps/cases/gps_parse_expected.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -7,9 +7,13 @@
"0.000000,0.000000,0.000000,0.000000,0.000000,0.000000,0,0,0,0,0.000000,0.000000,0,0,1.750000,0.000000,0,0,90.160004,T,0.000000,M,N,3.200000,K",
"55.672054,12.521564,0.000000,1231.293823,5540.323242,134733.000000,N,E,1,10,0.800000,24.900000,M,0,0.000000,0.000000,0,0,0.000000,0,0.000000,0,0,0.000000,0",
"55.672054,12.521564,0.000000,1231.293823,5540.323242,134733.000000,N,E,0,0,0.000000,0.000000,0,A,1.830000,113.000000,41112,0,0.000000,0,0.000000,0,0,0.000000,0",
"55.672054,12.521564,0.000000,1231.293823,5540.323242,134733.000000,N,E,0,0,0.000000,0.000000,0,V,1.830000,113.000000,41112,0,0.000000,0,0.000000,0,0,0.000000,0",
"55.672054,12.521564,0.000000,1231.293823,5540.323242,134733.000000,N,E,0,0,0.000000,0.000000,0,V,1.830000,113.000000,41112,0,0.000000,0,0.000000,0,0,0.000000,0",
"-55.672054,-12.521567,0.000000,1231.294067,5540.323242,134734.000000,S,W,1,10,0.800000,23.700001,M,0,0.000000,0.000000,0,0,0.000000,0,0.000000,0,0,0.000000,0",
"55.672054,12.521567,0.000000,1231.294067,5540.323242,134734.000000,N,E,0,0,0.000000,0.000000,0,A,1.230000,107.220001,41112,0,0.000000,0,0.000000,0,0,0.000000,0",
"0.000000,0.000000,0.000000,0.000000,0.000000,0.000000,0,0,0,0,0.000000,0.000000,0,0,0.000000,0.000000,0,0,0.000000,0,0.000000,0,0,0.000000,0",
"39.898003,-105.112549,0.000000,10506.752930,3953.880127,34138.000000,N,W,0,0,0.000000,0.000000,0,0,0.000000,0.000000,0,A,0.000000,0,0.000000,0,0,0.000000,0",
"51.150440,-114.030678,0.000000,11401.840820,5109.026367,202725.000000,N,W,0,0,0.000000,0.000000,0,0,0.000000,0.000000,0,A,0.000000,0,0.000000,0,0,0.000000,0",
"51.150440,-114.030678,0.000000,11401.840820,5109.026367,202725.000000,N,W,0,0,0.000000,0.000000,0,0,0.000000,0.000000,0,V,0.000000,0,0.000000,0,0,0.000000,0",
"51.150440,-114.030678,0.000000,11401.840820,5109.026367,202725.000000,N,W,0,0,0.000000,0.000000,0,0,0.000000,0.000000,0,V,0.000000,0,0.000000,0,0,0.000000,0",
"0.000000,0.000000,0.000000,0.000000,0.000000,0.000000,0,0,0,0,0.000000,0.000000,0,0,0.000000,0.000000,0,0,0.000000,0,0.000000,0,0,0.000000,0"
2 changes: 1 addition & 1 deletion _test/driver/gps/test_gps.c
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Original file line number Diff line number Diff line change
Expand Up @@ -138,7 +138,7 @@ void test_GPS_parse
/*------------------------------------------------------------------------------
Initializations
------------------------------------------------------------------------------*/
int num_cases = 15;
int num_cases = 19;
char buffer[200] = ""; // An NMEA message is 82 characters, but the way we parse may end up with more in order to represent the struct

// Source: https://github.com/esutton/gps-nmea-log-files/blob/master/AMOD_AGL3080_20121104_134730.txt
Expand Down
99 changes: 82 additions & 17 deletions gps/gps.c
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Original file line number Diff line number Diff line change
Expand Up @@ -59,6 +59,12 @@
Global Variables
------------------------------------------------------------------------------*/

/*------------------------------------------------------------------------------
Local Variables
------------------------------------------------------------------------------*/
static GPS_DATA gps_last_valid_rmc_data;
static GPS_DATA gps_last_valid_gll_data;

/*------------------------------------------------------------------------------
Procedures
------------------------------------------------------------------------------*/
Expand Down Expand Up @@ -280,12 +286,18 @@ int gps_mesg_validate(char *nmeastr){
* *
*******************************************************************************/
void GPS_parse(GPS_DATA* gps_ptr, char *GPSstrParse){




/* Get message type */
char token[8]; // Needs to be 8 chars for memory alignment
strncpy(token, GPSstrParse, 6);
token[6] = '\0';
int idx = 7; /* Skips "$GPXXX,"*/



/* Parse by message type */
if (!strcmp(token, "$GPGGA"))
{
Expand All @@ -303,27 +315,80 @@ if (!strcmp(token, "$GPGGA"))
}
else if (!strcmp(token, "$GPRMC"))
{
gps_ptr->utc_time = gps_string_to_float(GPSstrParse, &idx);
gps_ptr->rmc_status = gps_string_to_char(GPSstrParse, &idx); /* unused */
gps_ptr->nmea_latitude = gps_string_to_float(GPSstrParse, &idx);
gps_ptr->ns = gps_string_to_char(GPSstrParse, &idx);
gps_ptr->nmea_longitude = gps_string_to_float(GPSstrParse, &idx);
gps_ptr->ew = gps_string_to_char(GPSstrParse, &idx);
gps_ptr->speed_k = gps_string_to_float(GPSstrParse, &idx);
gps_ptr->course_d = gps_string_to_float(GPSstrParse, &idx);
gps_ptr->date = (int)(0.5 + gps_string_to_float(GPSstrParse, &idx));
gps_conv_latitude_longitude( gps_ptr );
/* Parse data */
float utc_time = gps_string_to_float(GPSstrParse, &idx);
char rmc_status = gps_string_to_char(GPSstrParse, &idx);
float nmea_latitude = gps_string_to_float(GPSstrParse, &idx);
char ns = gps_string_to_char(GPSstrParse, &idx);
float nmea_longitude = gps_string_to_float(GPSstrParse, &idx);
char ew = gps_string_to_char(GPSstrParse, &idx);
float speed_k = gps_string_to_float(GPSstrParse, &idx);
float course_d = gps_string_to_float(GPSstrParse, &idx);
int date = (int)(0.5 + gps_string_to_float(GPSstrParse, &idx));

/* Save status */
gps_ptr->rmc_status = rmc_status;

/* Save rest of data only if status is A: Active */
if ( rmc_status == 'A' )
{
gps_ptr->utc_time = utc_time;
gps_ptr->nmea_latitude = nmea_latitude;
gps_ptr->ns = ns;
gps_ptr->nmea_longitude = nmea_longitude;
gps_ptr->ew = ew;
gps_ptr->speed_k = speed_k;
gps_ptr->course_d = course_d;
gps_ptr->date = date;
gps_conv_latitude_longitude( gps_ptr );

/* Update last valid data */
gps_last_valid_rmc_data = *gps_ptr;
}
/* Discard new data, use last valid data instead if the status is V: Void */
else if ( rmc_status == 'V' )
{
*gps_ptr = gps_last_valid_rmc_data;

/* Re-save rmc_status since the previous statement may override it */
gps_ptr->rmc_status = rmc_status;
}
}
else if (!strcmp(token, "$GPGLL"))
{
gps_ptr->nmea_latitude = gps_string_to_float(GPSstrParse, &idx);
gps_ptr->ns = gps_string_to_char(GPSstrParse, &idx);
gps_ptr->nmea_longitude = gps_string_to_float(GPSstrParse, &idx);
gps_ptr->ew = gps_string_to_char(GPSstrParse, &idx);
gps_ptr->utc_time = gps_string_to_float(GPSstrParse, &idx);
gps_ptr->gll_status = gps_string_to_char(GPSstrParse, &idx);
gps_conv_latitude_longitude( gps_ptr );
/* Parse data */
float nmea_latitude = gps_string_to_float(GPSstrParse, &idx);
char ns = gps_string_to_char(GPSstrParse, &idx);
float nmea_longitude = gps_string_to_float(GPSstrParse, &idx);
char ew = gps_string_to_char(GPSstrParse, &idx);
float utc_time = gps_string_to_float(GPSstrParse, &idx);
char gll_status = gps_string_to_char(GPSstrParse, &idx);

/* Store status */
gps_ptr->gll_status = gll_status;

/* Save rest of data only if status is A: Data Valid */
if (gll_status == 'A')

@ETSells ETSells Aug 6, 2026

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oof ik i didnt follow parentheses spacing standards when i wrote this function so this is fine for consistency. still sadge, don't ever let sophomore me write code again

{
gps_ptr->nmea_latitude = nmea_latitude;
gps_ptr->ns = ns;
gps_ptr->nmea_longitude = nmea_longitude;
gps_ptr->ew = ew;
gps_ptr->utc_time = utc_time;
gps_conv_latitude_longitude( gps_ptr );

gps_last_valid_gll_data = *gps_ptr;
}
else if (gll_status == 'V')
{
*gps_ptr = gps_last_valid_gll_data;

/* Resave gll status since the previous statement may override it */
gps_ptr->gll_status = gll_status;
}
}


else if (!strcmp(token, "$GPVTG"))
{
gps_ptr->course_t = gps_string_to_float(GPSstrParse, &idx);
Expand Down