ISP1907 IQ data

[skzpvls26]

Hello, we are planning to evaluate several type of AoA algorithm, and we have ISP1907-AOA-DK kit from Insight-SiP
Is there any guideline you know to get IQ data from each antenna to calculate phase, and then finally calculate AoA through phase different.?

Here, can we access the IQ data / raw data from the ISP1907 accordingly as what we want.?
If not, then do you have other BLE kit for AoA purpose that the IQ data can be accessed.?
Thank you

[Simonr]

Hi

Unfortunately converting the raw IQ data to usable form will be beyond what our solution provide, as we only provide the HW and the AOA algorithm. The rest is expected that customers do themselves. The samples you can use for Direction Finding are the following from the nRF Connect SDK:

• Bluetooth: Direction finding central
• Bluetooth: Direction finding connectionless locator
• Bluetooth: Direction finding connectionless beacon
• Bluetooth: Direction finding peripheral

Raw IQ data must be converted into vector form to be reviewed properly. We don't have have any specific sample code showing this, but you can check out this page for information on the various formulas used to translate IQ data between polar and rectangular form. Please also see the Direction Finding whitepaper for more information.

Best regards,

Simon

[skzpvls26]

Hi Simonr 

Thank you for your detailed answer. We really appreciate that.

In simple way of having two antenas to calculate AoA, the phase for an antena can be calculated through the first equation below.

Then the phase different between two antenas can be calculated through the second. The phase different can also be obtained if we have AoA information ( theta).

If we know the phase different, then we can calculate the AoA accordingly as

Here, I am particularly curious about which one is provided by the kit .?
does it give the IQ data for each antenna, phi, phase different, or theta.? or does the kit calculate the AoA in different way.?

Thank you very much.

[Simonr]

The kit will only output raw IQ data, so the phase must be calculated and then translate the IQ data correctly. Unfortunately I don't have more than the already provided links on this.

Best regards,

Simon

[skzpvls26]

Thank you for your reply.!

One more thing about the raw IQ data from ISP1907. 

I see that there are 5 components in one IQ, 

I see here that the first two may indicate some index, 

What is the number displayed here ? are they related to the I Q and maybe RSSI data.?

Thank you

[Simonr]

Hi

What sample is this IQ data gotten from exactly?

Best regards,

Simon