IWR6843AOP: mmWave Radar chip and board selection for water spray quality detection

Peter Bramsen

Part Number: IWR6843AOP

I'm trying to figure out what particular setup might work to detect a spray of water infront of a radar chip.

I'm not necessarily concerned with range detection, but with quality of returned signal. I want to see how much attenuation I have of the signal, what the db loss on returned signal is etc. I'm trying to see if I can spot a change from one spray condition to another, starting at about a 5% change in returned signal. I want to see all the noise in the returned signal because that's what would tell me the quality and I'd like to look at the change in said signal.

The principal I'm basing this on is that weather radar looks at the returned signal from different sized water drops. The different size drops and variations in signal loss over time/distance allow them to determine droplet sized based on know attenuation and scatter for specific radar wavelengths.

I'm looking at these chips Millimeter Wave (mmWave) radar sensors | Products | TI.com and the eval boards to start.

Thank you,

Peter

over 3 years ago

0 zigang Yang over 3 years ago

TI__Mastermind 36325 points

Hi, Peter:

You can use any of the following radar EVM. For 77Ghz, you can try

https://www.ti.com/tool/IWR1843BOOST and https://www.ti.com/tool/IWR1642BOOST

For 60GHz, you can try https://www.ti.com/tool/IWR6843ISK

We did not have any demo that try to determine the rain drop size. For all these devices, you can use SDK out-of-box demo to try, information can be found at: https://dev.ti.com/tirex/explore/node?node=AHggQGbWR1hnlpFCdTprgg__VLyFKFf__LATEST

You may need to re-design the chirp configuration to best fit your application. The chirp design information can be found at https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/1011679/iwr6843aop-how-to-proceed-in-designing-testing-chirps

Of course, you may want to develop your own algorithm, and you will need to capture the ADC raw data, then you will need to use DCA1000 board and TI mmwave studio to achieve that.

Best,

Zigang

0 Peter Bramsen over 3 years ago in reply to zigang Yang

Prodigy 110 points

Zigang,

thank you for the info. do you know if there is a way to look at measure signal attenuation or signal return strenght? I.e. I sent out a signal at 10 db and got a response at -67 db?

Peter

0 Peter Bramsen over 3 years ago in reply to zigang Yang

Prodigy 110 points

Zigang,

Am I able to set doppler filtering (I.E. Doppler shift/no doppler shift0 with the waveICBoost board or do I need the DCA1000 for full datalogging? Im trying to figure out exactly how the currently hardware and software offerings filter out rain and if I can basically reverse that. I.E. ignore everything except the equivalent of rain. Are there other technical resources that I can reference for this purpose?

0 zigang Yang over 3 years ago in reply to Peter Bramsen

TI__Mastermind 36325 points

HI, Peter:

The TX power is given in the data sheet. You can find the TX/RX antenna gain for each EVM at TIREX antenna database https://dev.ti.com/tirex/explore/node?node=AKu-aTm5FIcxlwZJU1pLBw__VLyFKFf__LATEST

There is no easy way to measure the received signal power, because there is all these RX gain, processing gain and scaling inside the process. I would recommend you to get a corner reflector with known RCS and placed it at a known distance so you can derive the received power based on equation, then at the receive side, after the Doppler FFT, check the signal amplitude of the target range bin. And then when with other unknown target, you can use the received signal power relative to the corner reflector measurement to understand the RX power.

You will need DCA1000 for raw ADC data capture.

You can find some experience on the target detection through the rain https://training.ti.com/sense-world-ti-mmwave-see-through-rain-and-walls-and-detect-small-objects . There can be some signal attenuation with or without rain. And the target should still appears as a peak in the range-Doppler heatmap. Whether the rain itself cause enough reflection to be detectable, you will need to experience yourself.

Best,

Zigang

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IWR6843AOP: mmWave Radar chip and board selection for water spray quality detection