nRF91 Geolocation and Cell Triangulation

[mschweig]

Hi, 

I would like to implement cell triangulation with the nRF91 in order determine the location of the device via cellular. I already had a look at the available posts such as https://devzone.nordicsemi.com/f/nordic-q-a/44093/nrf9160-dk-geolocation-through-lte

However, the problems were not solved and it seems there was not much development around this topic.

According to the documentation the %NBRGRSRP command should return the neighbor cells which could be a good start for my purpose. Unfortunately, this command returns only "OK" and no information about cells.

I tested this command with the at_client and the latest modem firmware, while being connected to NB-IoT.

• How can this command be used, respectively is there another possibility for retrieving the neighbouring cells? 
• Is there already any approach avaible for cell triangulation? 

Thanks in advance, 

Manuel

[Jasu]

Hi Manuel,

Check new modem firmware version mfw_nrf9160_1.3.0 and AT&NCELLMEAS feature

[mschweig]

Hi, I checked NCELLMEAS of the new modem firmware, but I am only getting the information of my current cell. However, the module sees at least 3 cells, since there are 3 different networks available. 

Am I missing some prerequesits? I am using AT-client v1.5.1. 

[Jasu]

Could you try to repeat the same and now make sure that device (modem) is in idle state. You can see when modem enter idle by enabling unsolicited CSCON AT notifications.

1. Set first "AT+CSCON=1"

2. Trigger connection and other AT commands that you use as normally

3. Wait that device (modem) enter idle state. You should see "+CSCON: 0" notification

4. Now trigger AT%NCELLMEAS

[mschweig]

Hi, 

I just tried and triggered NCELLMEAS after CSCON:0, but same error. I am only receiving my current cell. 

[Håkon Alseth]

Hi,

 

Could you ensure that you are in PSM or eDRX while enabling/querying NCELLMEAS, and let it run for a while?

Some networks might support providing neighboring cells in connected mode, but we only do the measurement while we're in a power saving mode (PSM or eDRX).

 

Kind regards,

Håkon

[mschweig]

Hi, 

I just tried with PSM enabled but still same issue. I already sent a modem trace to Didrik.

Kind regards, 
Manuel

[Jasu]

Ok, can you also copy-past the AT response here. Just for reference.