IWR6843AOPEVM: 2D Capon

Yunlong

Intellectual 651 points

Part Number: IWR6843AOPEVM

Hi,

I'm using IWR6843AOPEVM, I have some questions about how to do 2D Capon when using IWR6843AOPEVM.

1. What's the means about “a 180deg phase inversion needs to be applied in software processing”？

2. If I want to do 2D capon, how to generate the covariance matrix?

Looking forward to your help.

Thanks
Yunlong

over 4 years ago

0 zigang Yang over 4 years ago

TI__Mastermind 40005 points

HI, Yunlong:

For your first question, the routing in the AOP antenna has caused 180 degree of phase difference between RX1/RX3 and RX2/RX4. So, if the received signal, we need to adjust these 180 degree of phase shifter to each antenna channel.

For your second question, you can find the 2D capon description in section 2.3.2 of https://www.ti.com/lit/ug/tidue71d/tidue71d.pdf?ts=1626807808928&ref_url=https%253A%252F%252Fwww.google.com%252F

The source code can be found at people counting demo https://dev.ti.com/tirex/explore/node?node=AF4jhFuBH13mLPnsCXgawg__VLyFKFf__LATEST

Best,

Zigang

0 Yunlong over 4 years ago in reply to zigang Yang

Intellectual 651 points

Hi Zigang,

Thanks for your help.

I still have one question:

I think Xnc can use 4 virtual antennas, such as [5, 7, 9, 11].

But, what's Xkc means? I think K means the detected points range index.

I want to know which antenna should be used? such as [4, 3, 12, 11]? How many virtual antennas need to be use when calculate elevation angle?

Best,

Yunlong

0 zigang Yang over 4 years ago in reply to Yunlong

TI__Mastermind 40005 points

Hi, Yunlong:

IF you are looking for range-azimuth heatmap, then you can use the antennas that has the same location in elevation direction , but different spacing in azimuth, such as [5, 7, 9, 11] or [6, 8, 10, 12]

IF you are looking for range-elevation heatmap, then you can use the antennas that has the same location in azimuth direction, but different in elevation. such as [4, 3, 12, 11] or [2, 1, 10, 9]

IF you are looking for azimuth-elevation 2D spectrum for every range, then you can use all 12 antennas. The method is given in the sub-section "Elevation Estimation with Capon BF".

For detailed implementation, you can check the reference code.

Best,

Zigang

0 Yunlong over 4 years ago in reply to zigang Yang

Intellectual 651 points

Hi Zigang,

Thanks for your help.

I'm looking for azimuth-elevation 2D spectrum for every range. But I don’t know the order of the 12 antennas. Can you please guide me?

Best,

Yunlong

0 zigang Yang over 4 years ago in reply to Yunlong

TI__Mastermind 40005 points

HI, Yunlong:

The order of 12 antenna is related to the chirp configuration. IF chirp-0 enables TX1,chirp-1 enables TX2, andchirp-2 enables TX3, then the order will be

TX1-RX1, TX1-RX2, TX1-RX3, TX1-RX4, TX2-RX1, TX2-RX2, TX2-RX3, TX2-RX4, TX3-RX1, TX3-RX2, TX3-RX3, TX3-RX4,

Just like the figure you attached in your original thread. But if you change the chirp definition, then the order will change accordingly.

Best,

Zigang

0 Yunlong over 4 years ago in reply to zigang Yang

Intellectual 651 points

Hi Zigang, thanks.

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IWR6843AOPEVM: 2D Capon