someone built an OPENSOURCE MILITARY RADAR that tracks multiple targets up to 20km away its called AERIS-10, full github repo schematics, PCB layouts, FPGA code, python GUI, everything under MIT license commercial phased array radar starts at $250,000. military surplus is $10,000-50,000 but its decades old analog junk with no electronic beam steering this does electronic beam steering at 10.5GHz, pulse compression, doppler processing, multi-target tracking on a real time map two versions: 3km range with patch antenna array, 20km range with 32x16 slotted waveguide array and GaN AMPLIFIERS custom frequency synthesizer, 16 front-end chips, FPGA doing all signal processing, GPS and IMU for ACCURATE target coordinates when the platform moves all gerber files included so you can order the PCBs and build it yourself one person built what defense contractors charge a quarter MILLION for and open sourced it