Minimum numSat value for Fix & Position

[Matha 1]

Hello,

I'm using the sample Spresense gnss sketch. I do get a reading where numSat=4 after a cold start and approximately 25 mins of readings. Unfortunately, no Fix and Position values are being written to the Serial monitor when numSat=4. The Type is reported as GPS. How long before a Fix is reported? (I've let it run for hours previously unattended but there has been no change in the Fix status).

FWIW, in the same general area, I run two ublox NEO-6M modules (which are GPS only) with their respective detachable antennae. Changing the Spresense antenna for an external mount is beyond my job grade, sadly.

Thanks.

Kind regards.

[Matha 1]

@Matha-1
Please consider the issue closed!

I started receiving Position data (to known precision) but still No-Fix status. Presently have 10 GPS satellites detected.

Kind regards.

[jens6151 0 1 1]

@Matha-1

I was having these issues too ... Maybe before closing the issue.

As you have no fix status, if you do a HOT_START, the GPS gives you the last position data known (saved in some persistent memory). This needs to be considered.

With 10 GPS satellites you should get a fix within about a minute. So it is strange that there is no fix.

Getting a fix really depends on your local conditions and the current time (satellite constellation).

In the end I challenged adding an antenna. I am no soldering pro and struggled for 2 hours using 4 connectors ... Not really recommended as the pads are below the connector only. The difference is (perceived) huge though.

[Matha 1]

@jens6151-0-1-1

The time required for the first fix from a cold start is generally proportional to the time required to download the Almanac data (my presumption). I turned on the reporting for GPS and GNSS and noticed that 21 satellites were detected but the sample gnss.ino sketch keeps switching between No-Fix and Fix every few minutes. While a more desirable placement of the stationary board would improve the situation, my target solution (once I have weatherproof case) will eliminate satellite reception angles.

Kind regards.

[jens6151 0 1 1]

@Matha-1
You are right for the time required for the first fix.

 gnss.ino sketch keeps switching between No-Fix and Fix every few minutes. 

You probably noticed that this sketch restarts the GPS on purpose every 5 minutes. See RESTART_CYCLE (60 * 5)

[Matha 1]

@jens6151-0-1-1

Yes, thanks!

Kind regards.