GPS RMC and pvt parsing

[Tron]

As far as I could see, only GGA NMEA sentences are enabled by default. I want to check if RMC sentences deliver positions faster, and in my prj.conf I do the following: 

CONFIG_NRF9160_GPS_NMEA_RMC=y
CONFIG_NRF9160_GPS_NMEA_GGA=n

My question, do the pvt parsing take into account RMC sentences when the trigger for the GPS handler is FIX, or do I have to parse the RMC sentences myself, and set my GPS trigger to NMEA?

[Bjørn Kvaale]

I cannot see any mention of CONFIG_NRF9160_GPS_NMEA_RMC or CONFIG_NRF9160_GPS_NMEA_GGA in the gps code. The only code I can see that may be relevant is the following in init_app:

	u16_t nmea_mask     = NRF_CONFIG_NMEA_GSV_MASK |
			      NRF_CONFIG_NMEA_GSA_MASK |
			      NRF_CONFIG_NMEA_GLL_MASK |
			      NRF_CONFIG_NMEA_GGA_MASK |
			      NRF_CONFIG_NMEA_RMC_MASK;

Regarding the quicker GPS fix, I have asked about this internally & will get back to you soon. It seems we are asking an external expert for some help regarding this.

[Tron]

When I look in the nrf9160_gps.c file in the drivers section of my project, I see that by default only gga sentences are enabled, 

In the c file, I see

#ifdef CONFIG_NRF9160_GPS_NMEA_GSV
nmea_mask |= NRF_CONFIG_NMEA_GSV_MASK;
#endif
#ifdef CONFIG_NRF9160_GPS_NMEA_GSA
nmea_mask |= NRF_CONFIG_NMEA_GSA_MASK;
#endif
#ifdef CONFIG_NRF9160_GPS_NMEA_GLL
nmea_mask |= NRF_CONFIG_NMEA_GLL_MASK;
#endif
#ifdef CONFIG_NRF9160_GPS_NMEA_GGA
nmea_mask |= NRF_CONFIG_NMEA_GGA_MASK;
#endif
#ifdef CONFIG_NRF9160_GPS_NMEA_RMC
nmea_mask |= NRF_CONFIG_NMEA_RMC_MASK;
#endif

And seggeg greys out the  not defined, and I see that only GGA is enabled. If I in my prj.conf defines the variables as described above, I see that RMC is enabled, but GGA is not. 

[Tron]

I have been testing, and i get fix relatively fast using RMC sentences. The GPS driver doesn't deliver a fix using the RMC sentences, it seems it uses only GGA to deliver fix events. 

In order to use RMC, I will have to manually parse the incoming NMEA sentences by hand. 

[Bjørn Kvaale]

Great to hear that you are making progress! Is there anything else I should ask about internally regarding RMC sentencing & parsing the NMEA sentences?