Angle of Arrival (AoA) Calculation Producing Unexpected Values

RE: Angle of Arrival (AoA) Calculation Producing Unexpected Values

Elfving — Mon, 28 Apr 2025 08:22:45 GMT

Great, Amanda will take care of you there.

Regards,

Elfving

RE: Angle of Arrival (AoA) Calculation Producing Unexpected Values

Louis Chen — Sun, 27 Apr 2025 16:48:36 GMT

Hi Elfving ,

I am using aoa mode, and it can be identified from the print.

CTE[0]: samples count 45, cte type AOA, slot durations: 2 [us], packet status CRC OK, RSSI -790
IQ sample content :
sample[0] = I:-7 Q:-11 RSSI:-790
sample[1] = I:12 Q:-9 RSSI:-790
sample[2] = I:7 Q:12 RSSI:-790
sample[3] = I:-16 Q:8 RSSI:-790
sample[4] = I:-4 Q:-15 RSSI:-790
sample[5] = I:16 Q:-5 RSSI:-790
sample[6] = I:5 Q:13 RSSI:-790
sample[7] = I:-16 Q:4 RSSI:-790
sample[8] = I:13 Q:30 RSSI:-790
sample[9] = I:14 Q:1 RSSI:-790
sample[10] = I:20 Q:-45 RSSI:-790
sample[11] = I:-8 Q:-8 RSSI:-790
sample[12] = I:5 Q:-30 RSSI:-790
sample[13] = I:-41 Q:-28 RSSI:-790
sample[14] = I:50 Q:-24 RSSI:-790
sample[15] = I:-18 Q:3 RSSI:-790
sample[16] = I:-32 Q:17 RSSI:-790
sample[17] = I:-1 Q:12 RSSI:-790
sample[18] = I:47 Q:25 RSSI:-790
sample[19] = I:6 Q:-10 RSSI:-790
sample[20] = I:29 Q:5 RSSI:-790
sample[21] = I:26 Q:-41 RSSI:-790
sample[22] = I:14 Q:58 RSSI:-790
sample[23] = I:-2 Q:-17 RSSI:-790
sample[24] = I:-15 Q:-31 RSSI:-790
sample[25] = I:-15 Q:-4 RSSI:-790
sample[26] = I:-26 Q:42 RSSI:-790
sample[27] = I:9 Q:5 RSSI:-790
sample[28] = I:-9 Q:27 RSSI:-790
sample[29] = I:37 Q:21 RSSI:-790
sample[30] = I:-56 Q:17 RSSI:-790
sample[31] = I:16 Q:-7 RSSI:-790
sample[32] = I:30 Q:-15 RSSI:-790
sample[33] = I:1 Q:-18 RSSI:-790
sample[34] = I:-45 Q:-23 RSSI:-790
sample[35] = I:-10 Q:9 RSSI:-790
sample[36] = I:-30 Q:-8 RSSI:-790
sample[37] = I:-21 Q:43 RSSI:-790
sample[38] = I:-21 Q:-53 RSSI:-790
sample[39] = I:2 Q:16 RSSI:-790
sample[40] = I:12 Q:28 RSSI:-790
sample[41] = I:19 Q:-2 RSSI:-790
sample[42] = I:22 Q:-42 RSSI:-790
sample[43] = I:-8 Q:-7 RSSI:-790
sample[44] = I:9 Q:-25 RSSI:-790

My issue link :

devzone.nordicsemi.com/.../angle-of-arrival-application-exception-the-nrf52833-dk-antenna-array-cannot-be-started-normally-gpio-is-not-switched

RE: Angle of Arrival (AoA) Calculation Producing Unexpected Values

Elfving — Fri, 25 Apr 2025 16:11:10 GMT

Hi Louis,

I see you've gotten an answer from Milad here. I am not familiar with the exact antenna array that you are using, though if you are using the default NCS samples for this then it being configured to AOD might be one potential issue.

Feel free to open a new case if you are still having issues with this.

Regards,

Elfving

RE: Angle of Arrival (AoA) Calculation Producing Unexpected Values

miladflores — Tue, 15 Apr 2025 07:19:42 GMT

Hi Louis,

If I remember correctly I did not turn on that pin since it was used for AoD rather than AoA.

You should not be able to receive CTE on the PCB antenna only.
Are you controlling what pins are set high/low on the nRF? Also, do you possess the complete datasheet provided by CoreHW?

FYI, I did switch antenna array from CHW1010-ANT1 to U-blox B10 antenna instead.

Best regards,
Milad

RE: Angle of Arrival (AoA) Calculation Producing Unexpected Values

Louis Chen — Mon, 14 Apr 2025 10:07:34 GMT

Hi Sir,

I have some questions and would like to ask you if it is convenient. I am currently using a similar configuration of NRF52833+Antenna (CHW1010-ANT1-1.0) as yours. How do I use your ANT RF SWITCH PIN9 (D0: Digital control input)?

Another question is, after setting the ANT pattern, I tried to connect to the CTE link AOA mode, but I found that my antenna array would not switch. I tried to measure from GPIO 3/4/28/29 but couldn't get it? Did you make any changes? I removed the ANT array and used the PCB antenna instead, but it didn't move at all.

RE: Angle of Arrival (AoA) Calculation Producing Unexpected Values

Elfving — Tue, 11 Mar 2025 14:20:00 GMT

No problem at all Milad 🙂

Let us know if there is anything else!

Regards,
Elfving

RE: Angle of Arrival (AoA) Calculation Producing Unexpected Values

miladflores — Tue, 11 Mar 2025 13:54:16 GMT

Thank you for your assistance Elfving!

Best regards,

Milad

RE: Angle of Arrival (AoA) Calculation Producing Unexpected Values

Elfving — Tue, 11 Mar 2025 08:06:48 GMT

I guess we do not have that much in regards to materials on this, though this previous response by another customer might be worth a look.

Regards,

Elfving

RE: Angle of Arrival (AoA) Calculation Producing Unexpected Values

miladflores — Tue, 11 Mar 2025 06:46:15 GMT

You are completely right about it looping through until there are no more samples. However, I still have a concern regarding the calibration with the reference sample, I cannot wrap my head around a way to figure it out and there is not much information out there, do you have any advice regarding this?

Milad

RE: Angle of Arrival (AoA) Calculation Producing Unexpected Values

Elfving — Mon, 10 Mar 2025 13:05:41 GMT

Precisely :)

Note that the pattern is just a list, and you can repeat antennas on there. I acctually think the pattern needs to loop back on the one used in the reference at one point for it to follow the spec.

The WP is great for the understanding, though it unfortunately mentions a few things that is not correct as to how the sample in the SDK works. The main use-case of the WP was to explain the HW limitations, though those are ofcourse more than what SW limits us to. The documentation from BLE SIG and the little documentation we have here is should be correct in case you find any discrepancies. Though let me know if you have questions, and I can help clear things up as well.

Elfving

RE: Angle of Arrival (AoA) Calculation Producing Unexpected Values

miladflores — Mon, 10 Mar 2025 12:10:01 GMT

[quote userid="103347" url="~/f/nordic-q-a/119525/angle-of-arrival-aoa-calculation-producing-unexpected-values/526358"]Did the WP clear things up for you regarding the antenna patterns?[/quote]

Yes, thank you for the clarification!
If I got it right, it means that the first antenna in the antenna pattern is used 8 times during the reference period and after the reference period the pattern goes on to the 2nd antenna in the pattern and loops through the whole pattern until all the samples have been collected.

Milad

RE: Angle of Arrival (AoA) Calculation Producing Unexpected Values

Elfving — Fri, 07 Mar 2025 13:36:39 GMT

[quote user="miladflores"]

In my cpunet.overlay I have set "dfe-antenna-num = <16>" since the antenna array consists of 8 antenna patches with polarization. Even numbers are horizontal and odd numbers are vertical.

[/quote]

I guess that depends mainly on the antenna, so that might be fine. Did the WP clear things up for you regarding the antenna patterns?

Regards,

Elfving

RE: Angle of Arrival (AoA) Calculation Producing Unexpected Values

miladflores — Fri, 07 Mar 2025 09:32:02 GMT

[quote userid="103347" url="~/f/nordic-q-a/119525/angle-of-arrival-aoa-calculation-producing-unexpected-values/525972"]It should be used to calibrate.[/quote]

And would that be by getting the frequency offset from the reference samples and then using it to correct the remaining samples? If so, I'm thinking of something like this:

[quote userid="103347" url="~/f/nordic-q-a/119525/angle-of-arrival-aoa-calculation-producing-unexpected-values/525972"]Yeah, although that depends a bit on your pattern length, and whether these numbers refer to antennas, or order to antenna pattern etc.[/quote]

In my cpunet.overlay I have set "dfe-antenna-num = <16>" since the antenna array consists of 8 antenna patches with polarization. Even numbers are horizontal and odd numbers are vertical.

[quote userid="103347" url="~/f/nordic-q-a/119525/angle-of-arrival-aoa-calculation-producing-unexpected-values/525972"]What NCS version are you using? I guess all NCS versions should work, but we've only gotten the locator QDID (and therefore officially checked the locator) from NCS 2.2 with SDC, which I guess can be an argument for using that one. The zephyr controller also has a QDID for the locator that goes with NCS2.2.[/quote]

I'm running NCS 2.9.

Milad

RE: Angle of Arrival (AoA) Calculation Producing Unexpected Values

Elfving — Wed, 05 Mar 2025 12:30:47 GMT

Hi,

Are you using just one reciever?

Our WP on DF typically clears up confusion regarding antenna switching patterns. Have you seen this?

[quote user=""]As I understood it, the first 8 samples are from the reference period and should not be used to calculate the AoA [/quote]

It should be used to calibrate.

[quote user=""]So the pattern goes 0 - 0 - 0 - 0 - 0- 0 - 0 - 0 - 1 - 2 - 3 - 4 - 5 - 6 - 7 - 0 - 1 - etc. Am I missing something here?[/quote]

Yeah, although that depends a bit on your pattern length, and whether these numbers refer to antennas, or order to antenna pattern etc.

What NCS version are you using? I guess all NCS versions should work, but we've only gotten the locator QDID (and therefore officially checked the locator) from NCS 2.2 with SDC, which I guess can be an argument for using that one. The zephyr controller also has a QDID for the locator that goes with NCS2.2.

Regards,

Elfving