CCS/LAUNCHXL-CC26X2R1: Understanding TI AoA solution

Inseob Kim

Tool/software: Code Composer Studio

Hi, I'm trying to understand the aoa document of TI.
http://dev.ti.com/tirex/explore/content/simplelink_cc13x2_26x2_sdk_3_30_00_03/docs/ble5stack/ble_user_guide/html/ble-stack-5.x-guide/localization-index-cc13x2_26x2.html#angle-compensation

But, I cannot understand the fundamental of angle compensation.

There are explanation about the antenna pairs and the values about p->gain, p->offset, channelOffset_A1,2 with a figure as below.

../_images/lab_tuning.png

I don't know what is the data from the lab and why there are need to offset apply gain, and also what is the graph.

1. Could you explain more detail about the theory?

2. Could you let me know a thesis if it is about this methodology?

Best regards,
Inseob

over 7 years ago

0 J Lindh over 7 years ago

TI__Guru 57865 points

HI Inseob,

Have you also reviewed the SLAs?

0 Clément over 7 years ago

TI__Guru** 101570 points

Hi Inseob,

The theory is pretty simple: some offset are noticed when using AoA in the lab (when we place the slave at 0 degrees, then we do not measure 0 degrees). So we use an offset to compensate this and display 0 when the slave is at 0 degrees.

Same for the gain: as the distance between the antennas is not the same, the variation of the phase versus the slave angle is not exactly the same for all the antennas pairs. As it is easier to have the same variation for all the antennas-pairs, we basically compensate this with a value that has been calculated after lab-measurements.

In summary, all these values are done to compensate the differences we have between the antennas. If you are using your custom antennas board, you have to modify the values by doing some measures in a lab.

I hope this will help,

Regards,

0 Inseob Kim over 7 years ago in reply to J Lindh

Intellectual 545 points

Hi, Joakim.

I don't know what is SLAs?

Can you give me the link about SLAs to review?

Best regards,
Inseob

0 Inseob Kim over 7 years ago in reply to Clément

Intellectual 545 points

Hi, Clément.

Thanks for your reply.

Your comment is helpful for the understanding.

How about gain, why the gain has an angle?

Best regards,
Inseob

0 J Lindh over 7 years ago in reply to Inseob Kim

TI__Guru 57865 points

0 Inseob Kim over 7 years ago in reply to J Lindh

Intellectual 545 points

Thanks Joakim.

I'm already read the documents and understood almost things briefly.

Can I ask what is SLA? I don't know the abbreviation of the word..

Regards,
Inseob

0 Clément over 7 years ago in reply to Inseob Kim

TI__Guru** 101570 points

In this case "gain" must be seen as a coefficient. If you want, assuming the real angle is y, the angle measured is x, then we have y = ax + b where a is called the gain and b the offset.

I hope this will help,

0 Clément over 7 years ago in reply to Inseob Kim

TI__Guru** 101570 points

SLA means Simple Link Academy :)

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CCS/LAUNCHXL-CC26X2R1: Understanding TI AoA solution