RE: GPS slow fix and unstable

taitk — Thu, 14 Oct 2021 09:34:35 GMT

Thanks Håkon,

That's clear for me. My board said PCA10090 1.0.0 2021.11.
As my thought, "using 4" means device chose 4 best, doesn't it?
Is there any way to improve signal strength? It's outside the window, and this is my best scene.
As my monitor, GPS soon get 3 satellites in used, but long after to get the 4th.
The situation when gps loses tracking should appear frequently, how could I improve for it to get track back fast from that?

Regards,
Taitk

RE: GPS slow fix and unstable

Håkon Alseth — Thu, 14 Oct 2021 08:50:36 GMT

Hello,

Your picture shows that you are tracking many satellites, but using 4.

If we decode the strings:

https://www.trimble.com/oem_receiverhelp/v4.44/en/NMEA-0183messages_GSV.html

We see that there's not many that has >30 dB/Hz signal strength, which is around the number you want to see to be able to track a satellite successfully.

[quote user=""] I've just got nrf9160dk[/quote]

Which version of the nRF9160DK do you have? Older versions, prior to v0.14.0, has a recommendation of using an external antenna.

With v0.14.0 and newer, you can safely use the on-board GPS antenna.

[quote user=""]

2. After got fix, device keep lost-fix and re-fix.

Is this normal or not? Please help me figure out

[/quote]

Do you mean that it successfully gets a fix, then after a while starts searching again? This is normal if the GPS loses track of a satellite (ie. it goes out of "line of sight"), and a new one comes into range.

Kind regards,

Håkon