NSA’s ANT Division Catalog of Exploits for Nearly Every Major Software/Hardware/Firmware is interesting reading on gadgets NSA is claimed to use to spy on you. There was some discussion on Facebook on of those devices were real or not asking for my comments on some of the devices if they are feasible or not.
LOUDAUTO concept seems to be feasible. The used PPM coding method is presented in papers and claimed low current consumption seems to be doable. The constant wave radar target illumination and listening to signal scattering back is feasible at least in distance like meters or tens of meters. I consulted one radio engineer on to verify if this part looks feasible and he said yes this kind of methods can be used.
The listed RF instruments for receiving the signal are real (Rohde & Schwarz FSH-series protable spectrum analyzers, etc). Suitable radar signal source for this could be PHOTOANGLO. Some more details LOUDAUTO can be found A Surprising Feature in the NSA’s Radar Bugs: A Neurophone! blog posting.