New research: your phone can do ultrasound sonar tracking against youhttps://www.privateinternetaccess.com/blog/2017/09/your-phone-can-now-be-turned-into-an-ultrasound-sonar-against-you-and-others/
New research shows that your phone and TV can be subverted into indoor tracking devices for your motion, using inaudible ultrasound sonar.