Android Bluetooth 5.1 Direction Finding (AoA / AoD) in android app.

[Tasawar Khaliq]

Hi,
    As an IoT Mobile app manager, my company goal is to provide development services for iOT-based (Android/ iOS) apps. We are currently developing an indoor map or positioning system product. As BLE 5.1 now supports direction finding of BLE devices so that users can track their location or position according to nearby Bluetooth 5.1-based beacons or devices.

We have an nRF52833 DK board-based device and Android mobile supporting Bluetooth 5.2 So how can I check the AoA /AoD or antenna Array whatsoever data is required to calculate position, in the nRF Connect app? Any info on Advertising data to check the direction data is available in the nRF52833 DK board which we have? OR by Default, the firmware of the nRF52833 DK board is not showing the direction-finding features and we have to write the firmware? If yes then from where I can get the demo firmware to test the direction-finding feature?

Also, we have an nRF52840 DK board but I think that not supports direction finding.

Please help and explain every concern in the question because we develop apps using the nordic board.

[Elfving]

Hello Tasawar,

 So how can I check the AoA /AoD or antenna Array whatsoever data is required to calculate position, in the nRF Connect app?

You can't get this data from the nRF Connect App. In order to calculate the distance using Bluetooth Direction Finding, you have to send packets with a CTE extension (I know that not all smartphones are able to use this, but I've seen a few that brag about being able to send CTE's).

What you need for a Direction Finding setup to work is to have a locator (reciever), and a tag (beacon). On the locator side, you also need an antenna array (eg. this one from Insight SiP). The CTE is then compared on each of these antennas, which is used to calculate I/Q values and from there calculate the angles. This procedure is also explained in further detail here in our whitepaper on direction finding.

If yes then from where I can get the demo firmware to test the direction-finding feature?

You can get the firmware to test direction finding in our nRF Connect SDK. There are samples for both the locator and tag, for both with and without connection. These will give you the I/Q data, but does not include an angle algorithm. That is something you will have to create yourself (note that this is no small undertaking, but everything you theoretically need is mentioned in the whitepaper).

Also, we have an nRF52840 DK board but I think that not supports direction finding.

Correct, only the nRF52833 and nRF5340 support both locator and tag roles. Starting off with the '33 sounds like a good choice.

Regards,

Elfving

[fgunnars]

Curious about this comment above "I know that not all smartphones are able to use this, but I've seen a few that brag about being able to send CTE's"

Any information about which ones that brag about CTE support?

I noted this app in Apple Store (https://apps.apple.com/tt/app/antble/id1620976703?platform=iphone). Does that mean that iPhones have support for CTE?

[Elfving]

fgunnars said:

I know that not all smartphones are able to use this, but I've seen a few that brag about being able to send CTE's

I was mainly thinking of Huawei Honor View 20. Last time we checked it wasn't supported by Android or iOS, and haven't seen any mention of it in later releases either.

fgunnars said:

Does that mean that iPhones have support for CTE?

I am not sure, but I do not think so.

Regards,

Elfving