Reverse Engineering the Soli Radar API for Military Applications

Hand-held and through-wall radar systems have been widely adopted for first responder safety and military applications. Current technology necessitates solutions that are expensive and bulky. Exploiting current consumer products with radar technology could achieve effects similar to what current technology provides. The example investigated is the Google Soli radar, designed for fine gesture detection to facilitate human-computer interaction. This feature is included on the Pixel 4 smartphone. Google has not publicly released the radar's application programming interface (API), making the Soli radar and its methods generally inaccessible to developers. Access to an API or a way to access information from the Soli hardware is a necessary first step in exploiting the radar for first responder and military applications. We used established reverse engineering methods to locate the packages and classes that receive information from the radar before passing it to consumer application packages within the Pixel 4. Through reverse engineering and dynamic hooking, we extracted information from the methods of the hardware abstraction layer package. The results showed it is possible to capture the Soli radar output via dynamic hooking and demonstrated its performance in detecting motion through walls.