Disable power saving and still get GNSS periodically (weekly) in Asset Tracker 2

[Marshall]

I'm using Asset Tracker V2

My device is permanently powered, and I would like a quick response time to commands sent from the cloud, so I have turned off the power saving features

CONFIG_MODEM_AUTO_REQUEST_POWER_SAVING_FEATURES=n

This works great, and the unit remains online all the time, with a quick response from cloud commands. 

However I would like to update the GNSS location every now and then to see if the unit has moved. 

How would I best achieve this? 

Thanks 

Marshall

[helsing]

Hi Marshall,

Just letting you know I have started looking into this.

[helsing]

However I would like to update the GNSS location every now and then to see if the unit has moved. 

How would I best achieve this? 

Check out the section on Real-time configurations. You may alter the Location timeout in order to retrieve the location more often. The default value is 300 seconds.

Do you keep your device in Active mode or Passive mode? If the device is in Passive mode, then the Passive Movement timeout is also relevant. If the no movement is detected, there will be an update after 3600 seconds, by default.

[Marshall]

Thanks, let me rephrase the question.

If the device never enters PSM then the GNSS will never work. 

What is the suggested method to get a GNSS fix when no power saving mode is implemented.?

Regards

Marshall

[helsing]

Thank you for rephrasing.

I would like a quick response time

How quick does the response time need to be?

If your modem has a fresh fix it could produce more fixes in RRC Idle for a limited time. However, you would need to accept longer response times every now and then to get a fix from scratch. RRC Idle is usually not enough without either eDRX or PSM in use in order to prolong the sleep interval of the LTE stack.  

If your application requires the device only to be mostly on, then eDRX could be part of the solution. You could experiment with different values to find a suiting compromise between latency for LTE and how long time it takes to get a fix.

In any case, consider A-GPS as it is much faster and because it will make it less  difficult to get a fix.

An alternative is to use an external GNSS module, and then use nRF9160 for LTE only. However, it might still be challenging to get a fix, considering the potential RF-interference from LTE. Please let me know if this is something you consider, and I could try to get some of my other team members who have more expertise in this area to comment on the topic.

[Marshall]

Thanks for the response. and apologies for not providing enough information. 

I would like a quick response time - during business hours. 

The user will be operating/testing the device from the cloud on occasion. during these operations I would like a quick response say <10sec. 

The unit is largely static and might move once a week. so I was thinking that a daily location update would be fine. 

So the ideal would be. 

1. no power savings during business hours so that we can obtain <10sec response time
2. 2:00am location update - update speed is not an issue, 
3. the rest of the time it can do the default Asset tracker stuff.

Regards

Marshall