Navigation Messages column in the GPSTest database

[Maud Barthélémy]

Dear Sean, 

I'm Maud, currently employed at GSC alongside Emilio. 

Our current focus involves compiling a comprehensive list of devices capable of interpreting INAV messages. This compilation serves as an initial stride toward leveraging the OSNMA service. 

As far as my understanding goes, if a device is listed in the GPSTest database as supporting Navigation Messages, it implies its capability to read INAV. Consequently, such devices can be deemed compatible with OSNMA. 

Could you confirm if my interpretation is correct? 

Many thanks,

Best regards 

Maud Barthelemy

[Sean Barbeau]

Hi Maud,

Thanks for reaching out!

Unfortunately the Android APIs themselves that I'm using to determine support for navigation messages don't give us specifics on what the APIs mean.

On Android S and higher, I use https://developer.android.com/reference/android/location/GnssCapabilities#hasNavigationMessages(), which says:

>Returns true if GNSS chipset supports navigation messages, false otherwise.

Below Android S, I use https://developer.android.com/reference/android/location/GnssNavigationMessage.Callback#STATUS_READY, which says:

>GNSS Navigation Messages are successfully being tracked, it will receive updates once they are available.

Beyond that, there is no guarantee on specifics, as GPSTest doesn't currently read the contents of the navigation message data.

I do have an issue open, though, to add specific observed navigation message types in the future (i.e., read the contents in GPSTest):

https://github.com/barbeau/gpstest/issues/522

Based on what the community has shared in the past, I seem to recall some devices only providing navigation messages for certain constellations. Or some other unexpected behavior - I'll see if I can dig up more info on this.

If anyone else's memory serves them better and you have links to past discussions on this topic, please feel free to chime in too.

Sean