changing the ncs nrf driver for agps sample

[paul_tanner]

I want to build on the agps sample for 9160-dk

This involves changing the destination and format of outputs to cloud

I saw that multiple GPS hits are consolidated and formatted in ncs/nrf/drivers/gps/gps_sim/gps_sim.c

I changed this file but it does not get re-complied when I use "west build -b nrf9160dk_nrf9160ns -p"

Is there a way to make this happen pls?

[Albrecht Markus Schellenberger]

Hello Paul,

Unless you haven’t changed that, the agps sample uses the nrf9160_gps drivers and not gps_sim by default.

prj.conf

CONFIG_NRF9160_GPS=y

../nrf/drivers/gps/CMakeLists.txt

 

add_subdirectory_ifdef(CONFIG_NRF9160_GPS nrf9160_gps)

If you want to keep your modifications separated from the original drivers, you can also add your own modified drivers to the application.

Regards,

Markus

[paul_tanner]

Thanks for that Markus.  It sheds light on the way the build works.

However, nrf9160_gps.c does not seem to format the output.  I identified gps_sim.c by looking for something like 

GPS_NMEA_SENTENCE "$GPGGA,%02d%02d%02d.200,%8.3f,%c,%09.3f,%c,1,12,1.0,0.0,M,0.0,M,,*%02X"

Where is this formatting done in the default version pls?

I see that some masks are referenced in main.c.  This suggests that the formatting may be performed in firmware by feeding it with masks such as NRF_GNSS_NMEA_GGA_MASK.  However, I don't see where any of these are defined. 

[Albrecht Markus Schellenberger]

Hello Paul,

Gps_sim is a simulation, which is why the NMEA string format is defined there.  For the nrf9160_gps, the formatting is done in the modem firmware, as you already mentioned. You can enable them by setting the CONFIG_NRF9160_GPS_NMEA_GGA option.

May I ask why you want to change the destination and formation? I wonder what you would like to achieve with that?

Regards,

Markus