US cops now have radar "x-ray vision", didn't tell anybody.

Doppler radar on a single chip has been around for quite a long time now, I remember reading about it in the early 1990's in Scientific American.

Using radar to look inside a house has been a thing for quite a while now as well. Because when there's radar-on-a-chip available to fiddle with, people fiddle with them and discover they can do things that are pretty interesting. Like they can detect the motions of a human breathing from outside a house. They can obviously spot a human moving around inside a house as well.

Well, it seems that somebody built some of these super Tom Swift radars. Rolled 'em out to cop departments all over the USA. One problem: they didn't tell anybody.

At least 50 U.S. law enforcement agencies have secretly equipped their officers with radar devices that allow them to effectively peer through the walls of houses to see whether anyone is inside, a practice raising new concerns about the extent of government surveillance.

Those agencies, including the FBI and the U.S. Marshals Service, began deploying the radar systems more than two years ago with little notice to the courts and no public disclosure of when or how they would be used. The technology raises legal and privacy issues because the U.S. Supreme Court has said officers generally cannot use high-tech sensors to tell them about the inside of a person's house without first obtaining a search warrant.

Obtaining a search warrant is of course something they have not been doing. They've been scanning to see if there's anybody home first and asking permission later.

Agents' use of the radars was largely unknown until December, when a federal appeals court in Denver said officers had used one before they entered a house to arrest a man wanted for violating his parole. The judges expressed alarm that agents had used the new technology without a search warrant, warning that "the government's warrantless use of such a powerful tool to search inside homes poses grave Fourth Amendment questions."

By then, however, the technology was hardly new. Federal contract records show the Marshals Service began buying the radars in 2012, and has so far spent at least $180,000 on them.

And the court has been letting them.

Agents arrested Denson for the parole violation and charged him with illegally possessing two firearms they found inside. The agents had a warrant for Denson's arrest but did not have a search warrant. Denson's lawyer sought to have the guns charge thrown out, in part because the search began with the warrantless use of the radar device.

Three judges on the federal 10th Circuit Court of Appeals upheld the search, and Denson's conviction, on other grounds. Still, the judges wrote, they had "little doubt that the radar device deployed here will soon generate many questions for this court."

Despite the fact that scanning a residence with any kind of sensor, be it thermal, radar or even a drug-sniffing dog without a warrant has been specifically disallowed by the Supreme Court of the USA.

Because its just too handy to be able to use penetrating imaging for fishing expeditions. It may not hold up in court, but if you do it secretly you can always find another reason to raid a guy's place if you try hard enough.

Incidentally there are drone-mounted versions of this technology available that can work at extended range. I would think a quadcopter would be large enough to carry something like that, their power consumption is relatively small and physically the whole guts of the unit will be the size of a cell-phone. There are also larger side-looking radar sets that can be mounted on an aircraft or dirigible which can image arbitrarily large areas. Just crank up the power and you can see inside stuff for miles.

Brings a whole new level of irony to the term "tinfoil hat" doesn't it?

Just thought y'all ought to know. Maybe get some aluminum siding on the house and mylar in those windows, eh?