Why does AGPS take a long time like 5 to 20 sec to fix?

[Yusuke]

<environment>
Windows10
ncs v1.3.0
modem fw v1.2.0
DK 0.9.0

I made one-shot agps app by modifying gps sample app. The behavior is this.

- download SUPL data from supl.google.com before first fixing
< loop >
- enable LNA
- turn on GPS(AT+CFUN=31)
- fix position
- turn off GPS(AT+CFUN=30)
- disable LNA
- sleep a few seconds
Then back to the loop head

I tested it under the open sky. 

The first fix is around 30 sec as SUPL data is downloaded and I guess an interference by LTE happens.

After that the app fixes positions at the interval of 5 to 20 sec. This is much longer than expected. As long as I remember, it should be 2 or 3 sec.

Why does it takes so long time? I know nRF9160 doesn't support GLONASS. 

[Stian Røed Hafskjold]

Hi, because of summer vacations there will be some delays in the response time here on Devzone. I will have a look at this on Monday next week. Hope that's ok. Sorry for the inconvenience.

[Yusuke]

That's fine. I've already known it. I'll be waiting for your reply

[Yusuke]

I figured out the cause of this issue. I initiated and started and close socket after I get the first fix every time. This causes the slow GPS fix. I initiate GPS socket only once and start/stop GPS repeatedly. Then hot start works out.

[mikael.kallberg]

Hi Yusuke.

Do you still have the code for the mentioned ?
I would be really happy if you do and would share it?
Thanks // Mike