IWR6843AOPEVM: Problems with Angle Estimation Using Virtual Antennas

Gary Lu

Part Number: IWR6843AOPEVM

Hello，

May I ask if the 180° phase problem in the red part mentioned here will affect my angle estimation? I use the TDM-MIMO mode to obtain the data. Now I want to use 4, 3, 12, and 11 in the virtual array for FFT processing. To obtain an estimate of the pitch angle, will the phase difference of the red part shown in the figure affect my angle estimation, or if I want to use the data of this virtual array, I must first change all the phases of the red part before proceeding to subsequent angles estimate?

Regards，

Gary

over 2 years ago

0 Nathan Block over 2 years ago

TI__Mastermind 37805 points

Hi Gary,

The phase inversion you're mentioning here should be taken care of in the processing chain by the antPhaseRot

antPhaseRot 1 -1 -1 1 1 -1 -1 1 1 -1 -1 1

Best,

Nate

0 Gary Lu over 2 years ago in reply to Nathan Block

TI__Intellectual 1660 points

Hello，

I still don't quite understand, does it mean that the data obtained from the TI provided data acquisition demo has already undergone phase inversion?

Regards，

Gary

0 Josh Dye over 2 years ago in reply to Gary Lu

TI__Mastermind 20901 points

Hi Gary,

Sorry for the delay here. Nate is currently out of office. He is expected to return tomorrow. Your patience is greatly appreciated.

Best Regards,

Josh

0 Nathan Block over 2 years ago in reply to Josh Dye

TI__Mastermind 37805 points

Hi Gary,

What data flows from the antennas through the ADC originally it does have that phase rotation. It is removed from the data through processing in the radar cube. If you take data off the device using one of the TI processing chains, then the phase inversion should be corrected, and all antennas should be in-phase with one another.

Best,

Nate

0 Gary Lu over 2 years ago in reply to Nathan Block

TI__Intellectual 1660 points

Hello，

Can you be more concise in your answer? I used DCA1000+iwr6843aopevm to collect. bin file data, and I used FFT processing on the virtual array of 4, 3, 12, and 11 to obtain the estimation of pitch angle. So, do I need to perform phase rotation in the red section now,

Regards，

Gary

0 Nathan Block over 2 years ago in reply to Gary Lu

TI__Mastermind 37805 points

Hi Gary,

In that case, yes you will need to compensate the angle with the phase rotation yourself.

Best,

Nate

0 Gary Lu over 2 years ago in reply to Nathan Block

TI__Intellectual 1660 points

Hello，

Okay, thanks, but can I ask why the 180 degree rotation occurs?

Regards，

Gary

0 Nathan Block over 2 years ago in reply to Gary Lu

TI__Mastermind 37805 points

Hi Gary,

See section 3.3

https://dev.ti.com/tirex/explore/node?a=1AslXXD__1.10.00.13&node=A__AIQPG9x7K34A8l4ZELgznA__radar_toolbox__1AslXXD__1.10.00.13

Best,

Nate

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IWR6843AOPEVM: Problems with Angle Estimation Using Virtual Antennas