Gone are the days when software-defined radio technologies prevailed, and we don’t miss them at all. one example: [Laakso Mikko’s] The research team established a Multi-channel receiver Use 21 cheap RTL-SDR dongles to create a phase coherent array. This is useful for everything from direction finding and passive radar or beamforming.This Code It can also be found on GitHub.
Phase consistency does require that the dongle’s tuner can turn off jitter. This means that this code only applies to dongles that use R820T/2. The project modified the dongle to use a common clock and switchable reference noise generator.
A single coupler can hold seven dongles, and the cost is about $180. The team used up to 5 of them to create an array of 35 receivers. The processing is a bit math intensive, some code is in Matlab.
In addition, some papers deal with improving the performance of the sparse array of receivers to approach the performance of a fully filled array. Obviously, even at such a low price, for cost, space and power considerations, fewer receivers are needed.
Of course, not everyone needs dozens of phase-coherent receiving channels, but if you do, it is good to know an inexpensive way to implement it.
RTL-SDR makes many projects that are difficult to complete in traditional ways easy. From medical equipment to satellites, a piece of cheap hardware seems to be able to do it all.