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I've been working with an FMCW Fast Chirp radar transceiver. Mainly, I've been looking at the Doppler range map but really it is not suitable as there is only one point per range/ speed and I want to build a better picture of the surroundings.

I came across the following article. The below picture struck me as excellent:

enter image description here

Does anyone know how I could generate a picture as shown on the right using radar?

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  • $\begingroup$ Can you create a synthetic aperture? $\endgroup$ – AnonSubmitter85 Dec 31 '17 at 17:55
  • $\begingroup$ The device will be in motion so it is a SAR by definition but my question is more how do I use the readings to produce the 3d map. $\endgroup$ – SeanJ Dec 31 '17 at 23:56
  • $\begingroup$ The specifics of the entire radar image formation chain are too involved for an answer here and would be better addressed by a book on the subject. If you want a 3-D image, however, you will need motion in 2-D as linear motion of the sensor will only allow for resolution in 2-D at once. $\endgroup$ – AnonSubmitter85 Jan 2 '18 at 18:28
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You still only get one range and one velocity line per radar observation.

You can, however, "scan" a region (that's why airport towers and ships have these rotating antennas) and get another axis of information.

The same can be achieved using digital beamforming, which, however, requires multiple signal chains, and specific antenna arrays. For a two-dimensional picture, you'd need an at least two-dimensional array of antennas. For the resolution displayed, you'd need both high bandwidth (think in the order of 1GHz) as well as small wavelength (think of beyond 76 GHz). So, I'd say, without a millimeter-wave lab, this is probably not achievable.

I've not seen pictures like that myself (the article says "source: NXP" without elaborating any further, so this might just as well be "artist's interpretation of what NXP wants to achieve in 10 years).

Whilst this resolution might be impossible to achieve with commodity hardware, in principle, SDRs that are MIMO-capable do exist. If you can get your hand on a 4x4 MIMO phase-aligned SDR system, you could, behind/infront ambiguities notwithstanding, build a simple patch antenna array of 2 rows / 2 columns parallel patches and build a digital beamforming radar with that. You'd probably want to avoid the problems of isolating RX from TX by having a separate array for TX and RX.

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