Synthetic Aperture Radar (SAR) is a technique that can generate high-resolution imagery through the use of radar microwaves on a moving platform. Placing the radar system on a moving platform allows the system to simulate a very large aperture. Combined with some clever algorithms, the result is very high resolution imagery available in all weather conditions.

Typically, SAR implementation is the domain of high-level military spy and commercial satellites such as ICEYE and Sentinel-1. However, on his blog, Henrik Forstén has shown that it's possible to create a homemade SAR system using an FPGA, ADC, and custom 6 GHz radar antennas mounted on an FPV drone. Henrik's blog explains his setup in detail, discussing the radar and RF design, link budget, FPGA, his custom PCB, focusing, and more.

The results are rather stunning images that look almost like a photograph. And not only was Henrik able to take images, but a video too, which can be seen on his blog post.