fail err(-11) when in DF,I i can get the iq samples,but i use them to caculate the angle of Tx,how to solve it?

RE: fail err(-11) when in DF,I i can get the iq samples,but i use them to caculate the angle of Tx,how to solve it?

user114049 — Mon, 23 May 2022 09:07:35 GMT

ok,thanks.i know whether other antenna array with thiis nordic board make some influence in IQ values.

as i said some days ago,i find that the IQ sample are so small.

I get the IQ sample from silab as next.

{
	"channel":	18,
	"rssi":	-55,
	"sequence":	173,
	"samples":	[1, -57, -56, -2, -3, 57, 56, 2, 3, -56, -56, -3, -3, 57, 55, 6, 36, 45, -32, -87, -21, -13, -13, -41, 58, -68, -84, 29, 81, -29, -22, 2, -84, -88, 54, 95, -9, -68, -6, 20, -111, 34, 85, -24, -20, -37, 54, 2, 21, 52, -16, -92, -18, -15, -7, -42, 68, -57, -87, 15, 84, -15, -22, -1, -64, -108, 40, 104, 1, -69, -10, 19, -114, 21, 88, -9, -13, -40, 53, 10, 12, 56, 0, -94, -16, -17, 1, -43, 78, -44, -88, -1, 86, 1, -22, -4, -45, -115, 21, 111, 14, -67, -13, 17, -118, 0, 88, 2, -5, -42, 51, 19, 0, 58, 14, -93, -12, -20, 7, -42, 83, -31, -86, -13, 85, 13, -20, -9, -25, -125, 0, 116, 26, -64, -15, 15, -119, -18, 86, 22, 0, -42, 46, 27, -8, 57, 31, -87, -8, -23, 13, -40, 88, -14, -84, -29, 82, 28, -19, -12, -1, -126, -18, 109]

The nrf52833 board with antenna array of silab as next as IQ values.

CTE[DE:86:9B:6D:43:F0 (random)]: samples count 45, cte type AOA, slot durations: 2 [us], packet status CRC OK, RSSI -580

IQ sample content :

sample[0] = I:-2 Q:13

sample[1] = I:0 Q:-14

sample[2] = I:-2 Q:13

sample[3] = I:1 Q:-14

sample[4] = I:-3 Q:12

sample[5] = I:2 Q:-14

sample[6] = I:-3 Q:13

sample[7] = I:2 Q:-14

sample[8] = I:10 Q:-8

sample[9] = I:-12 Q:-2

sample[10] = I:-9 Q:-10

sample[11] = I:0 Q:-3

sample[12] = I:3 Q:-10

sample[13] = I:-4 Q:5

sample[14] = I:4 Q:7

sample[15] = I:-5 Q:3

sample[16] = I:-6 Q:3

sample[17] = I:-28 Q:5

sample[18] = I:2 Q:-4

sample[19] = I:11 Q:3

sample[20] = I:-2 Q:-13

sample[21] = I:4 Q:-13

sample[22] = I:1 Q:-1

sample[23] = I:10 Q:-2

sample[24] = I:-7 Q:-2

sample[25] = I:-4 Q:7

sample[26] = I:-6 Q:-3

sample[27] = I:-6 Q:-4

sample[28] = I:-18 Q:-24

sample[29] = I:4 Q:-1

sample[30] = I:1 Q:11

sample[31] = I:8 Q:-9

sample[32] = I:12 Q:-4

sample[33] = I:1 Q:1

sample[34] = I:6 Q:7

sample[35] = I:-2 Q:-7

sample[36] = I:-9 Q:0

sample[37] = I:0 Q:-7

sample[38] = I:-1 Q:-7

sample[39] = I:11 Q:-27

sample[40] = I:2 Q:2

sample[41] = I:-10 Q:7

sample[42] = I:12 Q:1

sample[43] = I:9 Q:9

sample[44] = I:-1 Q:1

as the err(-11) problem,when i meet ,i will call back to you.

Thanks.

RE: fail err(-11) when in DF,I i can get the iq samples,but i use them to caculate the angle of Tx,how to solve it?

user106736 — Mon, 23 May 2022 08:54:27 GMT

From this answer by Simon:
"Please note that the output you see from these samples won't be the "finished" angle of arrival, as this just transmits the raw IQ data to your central device. It is up to you to add an AoA algorithm that handles these values and converts them into readable data. Nordic will not provide the direction finding algorithm, and customers/users are expected to get that elsewhere. In order to use the IQ data you get from the beacon you will need an AOA algorithm, which we don't provide. There is no point in looking at the raw data as it needs to be converted into vector form to review it properly. You can check out this page for information on the various formulas used to translate IQ data between polar and rectangular form. "

Regards,
Sigurd Hellesvik

RE: fail err(-11) when in DF,I i can get the iq samples,but i use them to caculate the angle of Tx,how to solve it?

user114049 — Mon, 23 May 2022 08:51:10 GMT

sorry,now i can't get this err code.

i think it is in CTE parser. I think that this err code is my device problem.

"The ISP1907-AOA-DK is based on our design, so you could have a look at their project.
If you need our design files, contact your regional sales manager"

as you menthion,i get the same files of amtenna array.The most files are the circuit diagram of aantenna array.

what is the more ,i want to get the more information of how to gert the angle of algorithm.

RE: fail err(-11) when in DF,I i can get the iq samples,but i use them to caculate the angle of Tx,how to solve it?

user106736 — Mon, 23 May 2022 08:39:13 GMT

The ISP1907-AOA-DK is based on our design, so you could have a look at their project.
If you need our design files, contact your regional sales manager.

[quote user="swz_nordic5340"]how to solve the err(-11) problem[/quote]

Which function returns the -11 error?

For some more information on the nRF Connect SDK samples for direction finding and their algorithms, see this answer by Simon.

Regards,
Sigurd Hellesvik

RE: fail err(-11) when in DF,I i can get the iq samples,but i use them to caculate the angle of Tx,how to solve it?

user114049 — Mon, 23 May 2022 06:32:43 GMT

ok,thanks.besides,I want to ask how to solve the err(-11) problem.I am sorry that my output code have't been saved.

Now i link the line with my device.I find that my err(-11) have disappeared.I want yo know what the err(-11) is linked to?

is there a device problem?

if you know,please tell me.Thanks for your advice.

besides this,i want toi know more information about your antenna array of 12.

because i want to get the calculation of the angle.As yiuy mentioned,the designe of antenna array is related to the algorithm.

I am looking forward to your answer.Thanks!

RE: fail err(-11) when in DF,I i can get the iq samples,but i use them to caculate the angle of Tx,how to solve it?

user106736 — Wed, 18 May 2022 12:05:39 GMT

Our Bluetooth: Direction finding central is designed for the Nordic Semiconductor design 12 patch antenna matrix.
You can use this with any other antenna. However, the algorithm will be different for different antennas.

I suggest that you ask the designers of your antenna about the algorithm for that antenna.

Regards,
Sigurd Hellesvik