Where do we save the GPS Ephemeris data?

[eyes999]

Hi team,

We have a customer who has some questions about GPS.

The questions are:

1. Where do we save the Ephemeris data when GPS code start? RAM or flash?
2. When use both NB-IOT and GPS functions, if the Modem enter into the PSM mode, after 30minutes, wake up from the PSM mode, what is the status of GPS? GPS will begin to cold start or hot start? They actually want to know whether the Ephemeris data is hold or not in PSM mode.

Thanks,

Jun

[Heidi-Irene Harvey Sollie]

Hi!

Where do we save the Ephemeris data when GPS code start? RAM or flash?

The GPS data is stored in RAM.

When use both NB-IOT and GPS functions, if the Modem enter into the PSM mode, after 30minutes, wake up from the PSM mode, what is the status of GPS? GPS will begin to cold start or hot start? They actually want to know whether the Ephemeris data is hold or not in PSM mode.

The GPS data is held in PSM mode, yes. 

If the GPS has accurate knowledge of all the prerequisites (time, location, satellite orbits), it will do a hot start. This will automatically happen if a new fix is requested within half an hour from the last successful fix. 

So, depending on how long ago the last successful fix took place, the GPS will either to a warm start or hot start. The fact that the modem was put into PSM mode is irrelevant. 

Best regards,

Heidi