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

[Håkon Alseth]

Hi,

 

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.

The modem will not search for neighboring cells unless the link quality is underneath a threshold: https://devzone.nordicsemi.com/f/nordic-q-a/57705/cannot-get-rsrp-values-of-multiple-nearby-nb-iot-base-stations-anymore-with-newer-modem-firmware/233902#233902

 

Do note that this AT command gives you the physical cell id, which is different from the one that you're trying to use for location:

https://devzone.nordicsemi.com/f/nordic-q-a/53462/physical-cell-id-of-the/216323#216323

 

We do not currently have any way to fetch the cell id of neighboring cells. If you contact your local regional sales manager (RSM for short), they might have additional information if this is a scenario that we plan to support in the future.

If you do not know the details of your RSM, please send me a direct message with your location and I'll provide the contact information.

 

Cheers,

Håkon

[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.