ARGUS-6 is the primary perception sensor: an active sonar that pings the water around the vehicle and builds an image from the echoes. Light dies within metres underwater — sound is how the vehicle sees.
It is the sensor the whole ARGUS-6 build series is about, from the array to the beamforming.
For engineers
ARGUS-6 is a circular array driven by digital beamforming: we form many receive beams in software from one ping, trading raw compute for the lack of a mechanically scanned head. The full signal chain is the subject of the build pack.