IWR1642BOOST: In mmWave Demo Visualizer, question for range of Doppler Heat Map

Wei Zhang

Part Number: IWR1642BOOST
Other Parts Discussed in Thread: IWR1642

Hi,

I got a question about how to measure the range with IWR1642.

As in Wikipedia, the Pulse-Doppler systems measure the range to objects by measuring the elapsed time between sending a pulse of radio energy and receiving a reflection of the object. Radio waves travel at the speed of light, so the distance to the object is the elapsed time multiplied by the speed of light, divided by two - there and back. Does IWR1642 measure range like this? If not, what principle does it use?

Thank you!

Kind regards,

Wei Zhang

over 4 years ago

0 Sabeeh Khan1 over 4 years ago

TI__Mastermind 30140 points

While what you say is true, the radar is not measuring the time of the emitted pulse. The radar pulses are frequency ramped signals, so the TX signal has an associated slope. The transmit and receive signals are mixed with each other to create an intermediate frequency (IF) signal. The distance equation would then look like this:

dst = (IF * speed of light) / ( 2 * slope of TX freq)

For more information, please watch our training series titled "Intro to mmWave Sensing":

https://training.ti.com/intro-mmwave-sensing-fmcw-radars-module-1-range-estimation

0 Wei Zhang over 4 years ago in reply to Sabeeh Khan1

Prodigy 215 points

Dear Sabeeh,

Thank you for your time. And I think now I know the principles of them and I will learn more in the training series.

Kind regards,

Hubery

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IWR1642BOOST: In mmWave Demo Visualizer, question for range of Doppler Heat Map