Thank you for your comment and catching this. I appreciate the correction of “Fdoppler=2*velocity*sin(theta)/wavelength” and will check up on the length required for SAR in the reference you listed.
The intention is to keep the explanations fairly high level and intuitive, so I did not try to go into the frequency domain options for implementation. The radar texts do a better job in this regard. I am glad it was of use to you, in despite of the fact you sound pretty knowledgeable in this area.
I am hoping to publish and present a paper on a high performance radar algorithm at RadarCon, if the results work out well. Best regards, Michael Parker
Great Radar and SAR Overview - However, I would like to make note of a couple slight inaccuracies in this section of the text.
First, upon performing the calculations for the resolvable distance of the radar system, the author claims that the path traversed by the SAR system must be twice that of a real antenna length to achieve similar performance in the azimuth domain. However, this is actually the opposite effect of the two-way propagation nature of SAR. Evidence of this can be found in "Understanding Radar Systems," by Kingsley & Quegan.
I would also like to highlight the fact that the section entitled "SAR Processing" details a method of correlation. Although the procedure implemented in the explanation is the most straight-forward approach and the best visual aid in the calculation, this may also be performed in the frequency domain. This allows the traditional approach, as well as the Doppler SAR approach, to capitalize on the efficiency of the FFT.
Lastly, in the section for SAR Doppler processing, the doppler shift is also twice that of normal, one-way systems (comm. systems, for example). An accurate approximation for the doppler shift is actually
Derivations for this expression can be found in the an edition of Skolnik's Radar Systems books.
Overall, this is a great series and has been a good supplement to my foray into the radar world. Thanks for your contribution and I look forward to any other articles you publish!
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