Kraken SDR has 5 receivers, all synchronized to the same time. There was a "passive" radar project that used its hardware but got shutdown.
https://hackaday.com/2022/11/19/open-source-passive-radar-ta...
apparently passive radar is governed by some US Munitions list:
US Munitions List, Category 11(a)(3)(xxvii): Bi-static/multi-static radar that exploits greater than 125 kHz bandwidth and is lower than 2 GHz center frequency to passively detect or track using radio frequency (RF) transmissions (e.g., commercial radio, television stations);